[RFC PATCH v2 0/3] usb: typec: Support for Alternate Modes

[RFC PATCH v2 0/3] usb: typec: Support for Alternate Modes

[Heikki Krogerus]

Hi guys,

This is second version of my proposal for more complete USB Type-C
Alternate Mode support. The original proposal can be read from here:
https://www.spinics.net/lists/linux-usb/msg161098.html

These patches now depend on series from Hans where he is introducing
mux handling support for USB Type-C and USB in general:
https://lkml.org/lkml/2018/3/2/340

The major difference compared to v1 is that I'm proposing change to
the sysfs ABI we have for the alternate mode devices. The files are
not changed, but they are moved to the parent directory from the
mode<index> folder. Since the alternate mode devices are not yet used
and in practice not supported in mainline, I felt brave enough to
propose that.

The reason for removing the mode<index> folder is because as in patch
1/3 I now create a device for every mode of every SVID, there will
never be more then one mode folder. I.e. the folder serves no purpose.
The mode<index> is still kept for now, but it's just deprecated.

There are no alternate mode drivers included yet in this version.


Original commit message (subject was "usb: typec: alternate mode
bus"):

The bus allows SVID specific communication with the partners to be
handled in separate drivers for each alternate mode.

Alternate mode handling happens with two separate logical devices:
1. Partner alternate mode devices which represent the alternate modes
   on the partner. The driver for them will handle the alternate mode
   specific communication with the partner using VDMs.
2. Port alternate mode devices which represent connections from the
   USB Type-C port to devices on the platform.

The drivers will be bind to the partner alternate modes. The alternate
mode drivers will need to deliver the result of the negotiated pin
configurations to the rest of the platform (towards the port alternate
mode devices). This series includes API for that, however, not the
final implementation yet.

The connections to the other devices on the platform the ports have
can be described by using the remote endpoint concept [1][2] on ACPI
and DT platforms, but I have no solution for the "platform data" case
where we have neither DT nor ACPI to describe the connections for us.

[1] Documentation/devicetree/bindings/graph.txt
[2] Documentation/acpi/dsd/graph.txt


Heikki Krogerus (3):
  usb: typec: Register a device for every mode
  usb: typec: Bus type for alternate modes
  usb: typec: tcpm: Support for Alternate Modes

 Documentation/ABI/obsolete/sysfs-class-typec |  48 +++
 Documentation/ABI/testing/sysfs-bus-typec    |  51 ++++
 Documentation/ABI/testing/sysfs-class-typec  |  62 +---
 Documentation/driver-api/usb/typec_bus.rst   | 143 +++++++++
 drivers/usb/typec/Makefile                   |   2 +-
 drivers/usb/typec/bus.c                      | 421 ++++++++++++++++++++++++++
 drivers/usb/typec/bus.h                      |  37 +++
 drivers/usb/typec/class.c                    | 424 ++++++++++++++++++---------
 drivers/usb/typec/tcpm.c                     | 156 +++++++---
 include/linux/mod_devicetable.h              |  15 +
 include/linux/usb/typec.h                    |  50 +---
 include/linux/usb/typec_altmode.h            | 136 +++++++++
 scripts/mod/devicetable-offsets.c            |   4 +
 scripts/mod/file2alias.c                     |  13 +
 14 files changed, 1285 insertions(+), 277 deletions(-)
 create mode 100644 Documentation/ABI/obsolete/sysfs-class-typec
 create mode 100644 Documentation/ABI/testing/sysfs-bus-typec
 create mode 100644 Documentation/driver-api/usb/typec_bus.rst
 create mode 100644 drivers/usb/typec/bus.c
 create mode 100644 drivers/usb/typec/bus.h
 create mode 100644 include/linux/usb/typec_altmode.h

-- 
2.16.1

[RFC PATCH v2 1/3] usb: typec: Register a device for every mode

[Heikki Krogerus]

Before a device was created for every discovered SVID, but
this will create a device for every discovered mode of every
SVID. The idea is to make it easier to create mode specific
drivers once a bus for the alternate mode is added.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/typec/class.c | 163 +++++++++++++++-------------------------------
 drivers/usb/typec/tcpm.c  |  45 ++++++-------
 include/linux/usb/typec.h |  34 +++-------
 3 files changed, 79 insertions(+), 163 deletions(-)

diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 53df10df2f9d..26eeab1491b7 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -13,31 +13,20 @@
 #include <linux/usb/typec.h>
 #include <linux/usb/typec_mux.h>
 
-struct typec_mode {
-	int				index;
+struct typec_altmode {
+	struct device			dev;
+	u16				svid;
+	u8				mode;
+
 	u32				vdo;
 	char				*desc;
 	enum typec_port_type		roles;
-
-	struct typec_altmode		*alt_mode;
-
 	unsigned int			active:1;
 
+	struct attribute		*attrs[5];
 	char				group_name[6];
 	struct attribute_group		group;
-	struct attribute		*attrs[5];
-	struct device_attribute		vdo_attr;
-	struct device_attribute		desc_attr;
-	struct device_attribute		active_attr;
-	struct device_attribute		roles_attr;
-};
-
-struct typec_altmode {
-	struct device			dev;
-	u16				svid;
-	int				n_modes;
-	struct typec_mode		modes[ALTMODE_MAX_MODES];
-	const struct attribute_group	*mode_groups[ALTMODE_MAX_MODES];
+	const struct attribute_group	*groups[2];
 };
 
 struct typec_plug {
@@ -186,13 +175,12 @@ static void typec_report_identity(struct device *dev)
 void typec_altmode_update_active(struct typec_altmode *alt, int mode,
 				 bool active)
 {
-	struct typec_mode *m = &alt->modes[mode];
 	char dir[6];
 
-	if (m->active == active)
+	if (alt->active == active)
 		return;
 
-	m->active = active;
+	alt->active = active;
 	snprintf(dir, sizeof(dir), "mode%d", mode);
 	sysfs_notify(&alt->dev.kobj, dir, "active");
 	kobject_uevent(&alt->dev.kobj, KOBJ_CHANGE);
@@ -220,42 +208,37 @@ struct typec_port *typec_altmode2port(struct typec_altmode *alt)
 EXPORT_SYMBOL_GPL(typec_altmode2port);
 
 static ssize_t
-typec_altmode_vdo_show(struct device *dev, struct device_attribute *attr,
-		       char *buf)
+vdo_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       vdo_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 
-	return sprintf(buf, "0x%08x\n", mode->vdo);
+	return sprintf(buf, "0x%08x\n", alt->vdo);
 }
+static DEVICE_ATTR_RO(vdo);
 
 static ssize_t
-typec_altmode_desc_show(struct device *dev, struct device_attribute *attr,
-			char *buf)
+description_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       desc_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 
-	return sprintf(buf, "%s\n", mode->desc ? mode->desc : "");
+	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
 }
+static DEVICE_ATTR_RO(description);
 
 static ssize_t
-typec_altmode_active_show(struct device *dev, struct device_attribute *attr,
-			  char *buf)
+active_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       active_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 
-	return sprintf(buf, "%s\n", mode->active ? "yes" : "no");
+	return sprintf(buf, "%s\n", alt->active ? "yes" : "no");
 }
 
 static ssize_t
-typec_altmode_active_store(struct device *dev, struct device_attribute *attr,
+active_store(struct device *dev, struct device_attribute *attr,
 			   const char *buf, size_t size)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       active_attr);
-	struct typec_port *port = typec_altmode2port(mode->alt_mode);
+	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_port *port = typec_altmode2port(alt);
 	bool activate;
 	int ret;
 
@@ -266,22 +249,22 @@ typec_altmode_active_store(struct device *dev, struct device_attribute *attr,
 	if (ret)
 		return ret;
 
-	ret = port->cap->activate_mode(port->cap, mode->index, activate);
+	ret = port->cap->activate_mode(port->cap, alt->mode, activate);
 	if (ret)
 		return ret;
 
 	return size;
 }
+static DEVICE_ATTR_RW(active);
 
 static ssize_t
-typec_altmode_roles_show(struct device *dev, struct device_attribute *attr,
-			 char *buf)
+supported_roles_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       roles_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 	ssize_t ret;
 
-	switch (mode->roles) {
+	switch (alt->roles) {
 	case TYPEC_PORT_SRC:
 		ret = sprintf(buf, "source\n");
 		break;
@@ -295,61 +278,13 @@ typec_altmode_roles_show(struct device *dev, struct device_attribute *attr,
 	}
 	return ret;
 }
+static DEVICE_ATTR_RO(supported_roles);
 
-static void typec_init_modes(struct typec_altmode *alt,
-			     const struct typec_mode_desc *desc, bool is_port)
+static void typec_altmode_release(struct device *dev)
 {
-	int i;
-
-	for (i = 0; i < alt->n_modes; i++, desc++) {
-		struct typec_mode *mode = &alt->modes[i];
-
-		/* Not considering the human readable description critical */
-		mode->desc = kstrdup(desc->desc, GFP_KERNEL);
-		if (desc->desc && !mode->desc)
-			dev_err(&alt->dev, "failed to copy mode%d desc\n", i);
-
-		mode->alt_mode = alt;
-		mode->vdo = desc->vdo;
-		mode->roles = desc->roles;
-		mode->index = desc->index;
-		sprintf(mode->group_name, "mode%d", desc->index);
-
-		sysfs_attr_init(&mode->vdo_attr.attr);
-		mode->vdo_attr.attr.name = "vdo";
-		mode->vdo_attr.attr.mode = 0444;
-		mode->vdo_attr.show = typec_altmode_vdo_show;
-
-		sysfs_attr_init(&mode->desc_attr.attr);
-		mode->desc_attr.attr.name = "description";
-		mode->desc_attr.attr.mode = 0444;
-		mode->desc_attr.show = typec_altmode_desc_show;
-
-		sysfs_attr_init(&mode->active_attr.attr);
-		mode->active_attr.attr.name = "active";
-		mode->active_attr.attr.mode = 0644;
-		mode->active_attr.show = typec_altmode_active_show;
-		mode->active_attr.store = typec_altmode_active_store;
-
-		mode->attrs[0] = &mode->vdo_attr.attr;
-		mode->attrs[1] = &mode->desc_attr.attr;
-		mode->attrs[2] = &mode->active_attr.attr;
-
-		/* With ports, list the roles that the mode is supported with */
-		if (is_port) {
-			sysfs_attr_init(&mode->roles_attr.attr);
-			mode->roles_attr.attr.name = "supported_roles";
-			mode->roles_attr.attr.mode = 0444;
-			mode->roles_attr.show = typec_altmode_roles_show;
-
-			mode->attrs[3] = &mode->roles_attr.attr;
-		}
-
-		mode->group.attrs = mode->attrs;
-		mode->group.name = mode->group_name;
+	struct typec_altmode *alt = to_altmode(dev);
 
-		alt->mode_groups[i] = &mode->group;
-	}
+	kfree(alt);
 }
 
 static ssize_t svid_show(struct device *dev, struct device_attribute *attr,
@@ -367,16 +302,6 @@ static struct attribute *typec_altmode_attrs[] = {
 };
 ATTRIBUTE_GROUPS(typec_altmode);
 
-static void typec_altmode_release(struct device *dev)
-{
-	struct typec_altmode *alt = to_altmode(dev);
-	int i;
-
-	for (i = 0; i < alt->n_modes; i++)
-		kfree(alt->modes[i].desc);
-	kfree(alt);
-}
-
 static const struct device_type typec_altmode_dev_type = {
 	.name = "typec_alternate_mode",
 	.groups = typec_altmode_groups,
@@ -395,13 +320,27 @@ typec_register_altmode(struct device *parent,
 		return ERR_PTR(-ENOMEM);
 
 	alt->svid = desc->svid;
-	alt->n_modes = desc->n_modes;
-	typec_init_modes(alt, desc->modes, is_typec_port(parent));
+	alt->mode = desc->mode;
+	alt->vdo = desc->vdo;
+	alt->roles = desc->roles;
+
+	alt->attrs[0] = &dev_attr_vdo.attr;
+	alt->attrs[1] = &dev_attr_description.attr;
+	alt->attrs[2] = &dev_attr_active.attr;
+
+	if (is_typec_port(parent))
+		alt->attrs[3] = &dev_attr_supported_roles.attr;
+
+	sprintf(alt->group_name, "mode%d", desc->mode);
+	alt->group.name = alt->group_name;
+	alt->group.attrs = alt->attrs;
+	alt->groups[0] = &alt->group;
 
 	alt->dev.parent = parent;
-	alt->dev.groups = alt->mode_groups;
+	alt->dev.groups = alt->groups;
 	alt->dev.type = &typec_altmode_dev_type;
-	dev_set_name(&alt->dev, "svid-%04x", alt->svid);
+	dev_set_name(&alt->dev, "%s-%04x:%u", dev_name(parent),
+		     alt->svid, alt->mode);
 
 	ret = device_register(&alt->dev);
 	if (ret) {
diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index 4e447e1e9ec6..bfb843ebffa6 100644
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -280,8 +280,8 @@ struct tcpm_port {
 	/* Alternate mode data */
 
 	struct pd_mode_data mode_data;
-	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX];
-	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX];
+	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
+	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
 
 	/* Deadline in jiffies to exit src_try_wait state */
 	unsigned long max_wait;
@@ -966,7 +966,6 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
 {
 	struct pd_mode_data *pmdata = &port->mode_data;
 	struct typec_altmode_desc *paltmode;
-	struct typec_mode_desc *pmode;
 	int i;
 
 	if (pmdata->altmodes >= ARRAY_SIZE(port->partner_altmode)) {
@@ -974,32 +973,28 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
 		return;
 	}
 
-	paltmode = &pmdata->altmode_desc[pmdata->altmodes];
-	memset(paltmode, 0, sizeof(*paltmode));
+	for (i = 1; i < cnt; i++) {
+		paltmode = &pmdata->altmode_desc[pmdata->altmodes];
+		memset(paltmode, 0, sizeof(*paltmode));
 
-	paltmode->svid = pmdata->svids[pmdata->svid_index];
+		paltmode->svid = pmdata->svids[pmdata->svid_index];
+		paltmode->mode = i;
+		paltmode->vdo = le32_to_cpu(payload[i]);
 
-	tcpm_log(port, " Alternate mode %d: SVID 0x%04x",
-		 pmdata->altmodes, paltmode->svid);
+		tcpm_log(port, " Alternate mode %d: SVID 0x%04x, VDO %d: 0x%08x",
+			 pmdata->altmodes, paltmode->svid,
+			 paltmode->mode, paltmode->vdo);
 
-	for (i = 1; i < cnt && paltmode->n_modes < ALTMODE_MAX_MODES; i++) {
-		pmode = &paltmode->modes[paltmode->n_modes];
-		memset(pmode, 0, sizeof(*pmode));
-		pmode->vdo = le32_to_cpu(payload[i]);
-		pmode->index = i - 1;
-		paltmode->n_modes++;
-		tcpm_log(port, "  VDO %d: 0x%08x",
-			 pmode->index, pmode->vdo);
-	}
-	port->partner_altmode[pmdata->altmodes] =
-		typec_partner_register_altmode(port->partner, paltmode);
-	if (!port->partner_altmode[pmdata->altmodes]) {
-		tcpm_log(port,
-			 "Failed to register alternate modes for SVID 0x%04x",
-			 paltmode->svid);
-		return;
+		port->partner_altmode[pmdata->altmodes] =
+			typec_partner_register_altmode(port->partner, paltmode);
+		if (!port->partner_altmode[pmdata->altmodes]) {
+			tcpm_log(port,
+				 "Failed to register modes for SVID 0x%04x",
+				 paltmode->svid);
+			return;
+		}
+		pmdata->altmodes++;
 	}
-	pmdata->altmodes++;
 }
 
 #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 672b39bb0adc..278b6b42c7ea 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -93,41 +93,23 @@ int typec_partner_set_identity(struct typec_partner *partner);
 int typec_cable_set_identity(struct typec_cable *cable);
 
 /*
- * struct typec_mode_desc - Individual Mode of an Alternate Mode
- * @index: Index of the Mode within the SVID
+ * struct typec_altmode_desc - USB Type-C Alternate Mode Descriptor
+ * @svid: Standard or Vendor ID
+ * @mode: Index of the Mode
  * @vdo: VDO returned by Discover Modes USB PD command
- * @desc: Optional human readable description of the mode
  * @roles: Only for ports. DRP if the mode is available in both roles
  *
- * Description of a mode of an Alternate Mode which a connector, cable plug or
- * partner supports. Every mode will have it's own sysfs group. The details are
- * the VDO returned by discover modes command, description for the mode and
- * active flag telling has the mode being entered or not.
+ * Description of an Alternate Mode which a connector, cable plug or partner
+ * supports.
  */
-struct typec_mode_desc {
-	int			index;
+struct typec_altmode_desc {
+	u16			svid;
+	u8			mode;
 	u32			vdo;
-	char			*desc;
 	/* Only used with ports */
 	enum typec_port_type	roles;
 };
 
-/*
- * struct typec_altmode_desc - USB Type-C Alternate Mode Descriptor
- * @svid: Standard or Vendor ID
- * @n_modes: Number of modes
- * @modes: Array of modes supported by the Alternate Mode
- *
- * Representation of an Alternate Mode that has SVID assigned by USB-IF. The
- * array of modes will list the modes of a particular SVID that are supported by
- * a connector, partner of a cable plug.
- */
-struct typec_altmode_desc {
-	u16			svid;
-	int			n_modes;
-	struct typec_mode_desc	modes[ALTMODE_MAX_MODES];
-};
-
 struct typec_altmode
 *typec_partner_register_altmode(struct typec_partner *partner,
 				const struct typec_altmode_desc *desc);
-- 
2.16.1

[RFC,v2,1/3] usb: typec: Register a device for every mode

[Heikki Krogerus]

Before a device was created for every discovered SVID, but
this will create a device for every discovered mode of every
SVID. The idea is to make it easier to create mode specific
drivers once a bus for the alternate mode is added.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/typec/class.c | 163 +++++++++++++++-------------------------------
 drivers/usb/typec/tcpm.c  |  45 ++++++-------
 include/linux/usb/typec.h |  34 +++-------
 3 files changed, 79 insertions(+), 163 deletions(-)

diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 53df10df2f9d..26eeab1491b7 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -13,31 +13,20 @@
 #include <linux/usb/typec.h>
 #include <linux/usb/typec_mux.h>
 
-struct typec_mode {
-	int				index;
+struct typec_altmode {
+	struct device			dev;
+	u16				svid;
+	u8				mode;
+
 	u32				vdo;
 	char				*desc;
 	enum typec_port_type		roles;
-
-	struct typec_altmode		*alt_mode;
-
 	unsigned int			active:1;
 
+	struct attribute		*attrs[5];
 	char				group_name[6];
 	struct attribute_group		group;
-	struct attribute		*attrs[5];
-	struct device_attribute		vdo_attr;
-	struct device_attribute		desc_attr;
-	struct device_attribute		active_attr;
-	struct device_attribute		roles_attr;
-};
-
-struct typec_altmode {
-	struct device			dev;
-	u16				svid;
-	int				n_modes;
-	struct typec_mode		modes[ALTMODE_MAX_MODES];
-	const struct attribute_group	*mode_groups[ALTMODE_MAX_MODES];
+	const struct attribute_group	*groups[2];
 };
 
 struct typec_plug {
@@ -186,13 +175,12 @@ static void typec_report_identity(struct device *dev)
 void typec_altmode_update_active(struct typec_altmode *alt, int mode,
 				 bool active)
 {
-	struct typec_mode *m = &alt->modes[mode];
 	char dir[6];
 
-	if (m->active == active)
+	if (alt->active == active)
 		return;
 
-	m->active = active;
+	alt->active = active;
 	snprintf(dir, sizeof(dir), "mode%d", mode);
 	sysfs_notify(&alt->dev.kobj, dir, "active");
 	kobject_uevent(&alt->dev.kobj, KOBJ_CHANGE);
@@ -220,42 +208,37 @@ struct typec_port *typec_altmode2port(struct typec_altmode *alt)
 EXPORT_SYMBOL_GPL(typec_altmode2port);
 
 static ssize_t
-typec_altmode_vdo_show(struct device *dev, struct device_attribute *attr,
-		       char *buf)
+vdo_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       vdo_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 
-	return sprintf(buf, "0x%08x\n", mode->vdo);
+	return sprintf(buf, "0x%08x\n", alt->vdo);
 }
+static DEVICE_ATTR_RO(vdo);
 
 static ssize_t
-typec_altmode_desc_show(struct device *dev, struct device_attribute *attr,
-			char *buf)
+description_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       desc_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 
-	return sprintf(buf, "%s\n", mode->desc ? mode->desc : "");
+	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
 }
+static DEVICE_ATTR_RO(description);
 
 static ssize_t
-typec_altmode_active_show(struct device *dev, struct device_attribute *attr,
-			  char *buf)
+active_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       active_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 
-	return sprintf(buf, "%s\n", mode->active ? "yes" : "no");
+	return sprintf(buf, "%s\n", alt->active ? "yes" : "no");
 }
 
 static ssize_t
-typec_altmode_active_store(struct device *dev, struct device_attribute *attr,
+active_store(struct device *dev, struct device_attribute *attr,
 			   const char *buf, size_t size)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       active_attr);
-	struct typec_port *port = typec_altmode2port(mode->alt_mode);
+	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_port *port = typec_altmode2port(alt);
 	bool activate;
 	int ret;
 
@@ -266,22 +249,22 @@ typec_altmode_active_store(struct device *dev, struct device_attribute *attr,
 	if (ret)
 		return ret;
 
-	ret = port->cap->activate_mode(port->cap, mode->index, activate);
+	ret = port->cap->activate_mode(port->cap, alt->mode, activate);
 	if (ret)
 		return ret;
 
 	return size;
 }
+static DEVICE_ATTR_RW(active);
 
 static ssize_t
-typec_altmode_roles_show(struct device *dev, struct device_attribute *attr,
-			 char *buf)
+supported_roles_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
 {
-	struct typec_mode *mode = container_of(attr, struct typec_mode,
-					       roles_attr);
+	struct typec_altmode *alt = to_altmode(dev);
 	ssize_t ret;
 
-	switch (mode->roles) {
+	switch (alt->roles) {
 	case TYPEC_PORT_SRC:
 		ret = sprintf(buf, "source\n");
 		break;
@@ -295,61 +278,13 @@ typec_altmode_roles_show(struct device *dev, struct device_attribute *attr,
 	}
 	return ret;
 }
+static DEVICE_ATTR_RO(supported_roles);
 
-static void typec_init_modes(struct typec_altmode *alt,
-			     const struct typec_mode_desc *desc, bool is_port)
+static void typec_altmode_release(struct device *dev)
 {
-	int i;
-
-	for (i = 0; i < alt->n_modes; i++, desc++) {
-		struct typec_mode *mode = &alt->modes[i];
-
-		/* Not considering the human readable description critical */
-		mode->desc = kstrdup(desc->desc, GFP_KERNEL);
-		if (desc->desc && !mode->desc)
-			dev_err(&alt->dev, "failed to copy mode%d desc\n", i);
-
-		mode->alt_mode = alt;
-		mode->vdo = desc->vdo;
-		mode->roles = desc->roles;
-		mode->index = desc->index;
-		sprintf(mode->group_name, "mode%d", desc->index);
-
-		sysfs_attr_init(&mode->vdo_attr.attr);
-		mode->vdo_attr.attr.name = "vdo";
-		mode->vdo_attr.attr.mode = 0444;
-		mode->vdo_attr.show = typec_altmode_vdo_show;
-
-		sysfs_attr_init(&mode->desc_attr.attr);
-		mode->desc_attr.attr.name = "description";
-		mode->desc_attr.attr.mode = 0444;
-		mode->desc_attr.show = typec_altmode_desc_show;
-
-		sysfs_attr_init(&mode->active_attr.attr);
-		mode->active_attr.attr.name = "active";
-		mode->active_attr.attr.mode = 0644;
-		mode->active_attr.show = typec_altmode_active_show;
-		mode->active_attr.store = typec_altmode_active_store;
-
-		mode->attrs[0] = &mode->vdo_attr.attr;
-		mode->attrs[1] = &mode->desc_attr.attr;
-		mode->attrs[2] = &mode->active_attr.attr;
-
-		/* With ports, list the roles that the mode is supported with */
-		if (is_port) {
-			sysfs_attr_init(&mode->roles_attr.attr);
-			mode->roles_attr.attr.name = "supported_roles";
-			mode->roles_attr.attr.mode = 0444;
-			mode->roles_attr.show = typec_altmode_roles_show;
-
-			mode->attrs[3] = &mode->roles_attr.attr;
-		}
-
-		mode->group.attrs = mode->attrs;
-		mode->group.name = mode->group_name;
+	struct typec_altmode *alt = to_altmode(dev);
 
-		alt->mode_groups[i] = &mode->group;
-	}
+	kfree(alt);
 }
 
 static ssize_t svid_show(struct device *dev, struct device_attribute *attr,
@@ -367,16 +302,6 @@ static struct attribute *typec_altmode_attrs[] = {
 };
 ATTRIBUTE_GROUPS(typec_altmode);
 
-static void typec_altmode_release(struct device *dev)
-{
-	struct typec_altmode *alt = to_altmode(dev);
-	int i;
-
-	for (i = 0; i < alt->n_modes; i++)
-		kfree(alt->modes[i].desc);
-	kfree(alt);
-}
-
 static const struct device_type typec_altmode_dev_type = {
 	.name = "typec_alternate_mode",
 	.groups = typec_altmode_groups,
@@ -395,13 +320,27 @@ typec_register_altmode(struct device *parent,
 		return ERR_PTR(-ENOMEM);
 
 	alt->svid = desc->svid;
-	alt->n_modes = desc->n_modes;
-	typec_init_modes(alt, desc->modes, is_typec_port(parent));
+	alt->mode = desc->mode;
+	alt->vdo = desc->vdo;
+	alt->roles = desc->roles;
+
+	alt->attrs[0] = &dev_attr_vdo.attr;
+	alt->attrs[1] = &dev_attr_description.attr;
+	alt->attrs[2] = &dev_attr_active.attr;
+
+	if (is_typec_port(parent))
+		alt->attrs[3] = &dev_attr_supported_roles.attr;
+
+	sprintf(alt->group_name, "mode%d", desc->mode);
+	alt->group.name = alt->group_name;
+	alt->group.attrs = alt->attrs;
+	alt->groups[0] = &alt->group;
 
 	alt->dev.parent = parent;
-	alt->dev.groups = alt->mode_groups;
+	alt->dev.groups = alt->groups;
 	alt->dev.type = &typec_altmode_dev_type;
-	dev_set_name(&alt->dev, "svid-%04x", alt->svid);
+	dev_set_name(&alt->dev, "%s-%04x:%u", dev_name(parent),
+		     alt->svid, alt->mode);
 
 	ret = device_register(&alt->dev);
 	if (ret) {
diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index 4e447e1e9ec6..bfb843ebffa6 100644
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -280,8 +280,8 @@ struct tcpm_port {
 	/* Alternate mode data */
 
 	struct pd_mode_data mode_data;
-	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX];
-	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX];
+	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
+	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
 
 	/* Deadline in jiffies to exit src_try_wait state */
 	unsigned long max_wait;
@@ -966,7 +966,6 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
 {
 	struct pd_mode_data *pmdata = &port->mode_data;
 	struct typec_altmode_desc *paltmode;
-	struct typec_mode_desc *pmode;
 	int i;
 
 	if (pmdata->altmodes >= ARRAY_SIZE(port->partner_altmode)) {
@@ -974,32 +973,28 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
 		return;
 	}
 
-	paltmode = &pmdata->altmode_desc[pmdata->altmodes];
-	memset(paltmode, 0, sizeof(*paltmode));
+	for (i = 1; i < cnt; i++) {
+		paltmode = &pmdata->altmode_desc[pmdata->altmodes];
+		memset(paltmode, 0, sizeof(*paltmode));
 
-	paltmode->svid = pmdata->svids[pmdata->svid_index];
+		paltmode->svid = pmdata->svids[pmdata->svid_index];
+		paltmode->mode = i;
+		paltmode->vdo = le32_to_cpu(payload[i]);
 
-	tcpm_log(port, " Alternate mode %d: SVID 0x%04x",
-		 pmdata->altmodes, paltmode->svid);
+		tcpm_log(port, " Alternate mode %d: SVID 0x%04x, VDO %d: 0x%08x",
+			 pmdata->altmodes, paltmode->svid,
+			 paltmode->mode, paltmode->vdo);
 
-	for (i = 1; i < cnt && paltmode->n_modes < ALTMODE_MAX_MODES; i++) {
-		pmode = &paltmode->modes[paltmode->n_modes];
-		memset(pmode, 0, sizeof(*pmode));
-		pmode->vdo = le32_to_cpu(payload[i]);
-		pmode->index = i - 1;
-		paltmode->n_modes++;
-		tcpm_log(port, "  VDO %d: 0x%08x",
-			 pmode->index, pmode->vdo);
-	}
-	port->partner_altmode[pmdata->altmodes] =
-		typec_partner_register_altmode(port->partner, paltmode);
-	if (!port->partner_altmode[pmdata->altmodes]) {
-		tcpm_log(port,
-			 "Failed to register alternate modes for SVID 0x%04x",
-			 paltmode->svid);
-		return;
+		port->partner_altmode[pmdata->altmodes] =
+			typec_partner_register_altmode(port->partner, paltmode);
+		if (!port->partner_altmode[pmdata->altmodes]) {
+			tcpm_log(port,
+				 "Failed to register modes for SVID 0x%04x",
+				 paltmode->svid);
+			return;
+		}
+		pmdata->altmodes++;
 	}
-	pmdata->altmodes++;
 }
 
 #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 672b39bb0adc..278b6b42c7ea 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -93,41 +93,23 @@ int typec_partner_set_identity(struct typec_partner *partner);
 int typec_cable_set_identity(struct typec_cable *cable);
 
 /*
- * struct typec_mode_desc - Individual Mode of an Alternate Mode
- * @index: Index of the Mode within the SVID
+ * struct typec_altmode_desc - USB Type-C Alternate Mode Descriptor
+ * @svid: Standard or Vendor ID
+ * @mode: Index of the Mode
  * @vdo: VDO returned by Discover Modes USB PD command
- * @desc: Optional human readable description of the mode
  * @roles: Only for ports. DRP if the mode is available in both roles
  *
- * Description of a mode of an Alternate Mode which a connector, cable plug or
- * partner supports. Every mode will have it's own sysfs group. The details are
- * the VDO returned by discover modes command, description for the mode and
- * active flag telling has the mode being entered or not.
+ * Description of an Alternate Mode which a connector, cable plug or partner
+ * supports.
  */
-struct typec_mode_desc {
-	int			index;
+struct typec_altmode_desc {
+	u16			svid;
+	u8			mode;
 	u32			vdo;
-	char			*desc;
 	/* Only used with ports */
 	enum typec_port_type	roles;
 };
 
-/*
- * struct typec_altmode_desc - USB Type-C Alternate Mode Descriptor
- * @svid: Standard or Vendor ID
- * @n_modes: Number of modes
- * @modes: Array of modes supported by the Alternate Mode
- *
- * Representation of an Alternate Mode that has SVID assigned by USB-IF. The
- * array of modes will list the modes of a particular SVID that are supported by
- * a connector, partner of a cable plug.
- */
-struct typec_altmode_desc {
-	u16			svid;
-	int			n_modes;
-	struct typec_mode_desc	modes[ALTMODE_MAX_MODES];
-};
-
 struct typec_altmode
 *typec_partner_register_altmode(struct typec_partner *partner,
 				const struct typec_altmode_desc *desc);

[RFC PATCH v2 2/3] usb: typec: Bus type for alternate modes

[Heikki Krogerus]

Introducing a simple bus for the alternate modes. Bus allows
binding drivers to the discovered alternate modes the
partners support.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 Documentation/ABI/obsolete/sysfs-class-typec |  48 +++
 Documentation/ABI/testing/sysfs-bus-typec    |  51 ++++
 Documentation/ABI/testing/sysfs-class-typec  |  62 +---
 Documentation/driver-api/usb/typec_bus.rst   | 143 +++++++++
 drivers/usb/typec/Makefile                   |   2 +-
 drivers/usb/typec/bus.c                      | 421 +++++++++++++++++++++++++++
 drivers/usb/typec/bus.h                      |  37 +++
 drivers/usb/typec/class.c                    | 325 +++++++++++++++++----
 include/linux/mod_devicetable.h              |  15 +
 include/linux/usb/typec.h                    |  16 +-
 include/linux/usb/typec_altmode.h            | 136 +++++++++
 scripts/mod/devicetable-offsets.c            |   4 +
 scripts/mod/file2alias.c                     |  13 +
 13 files changed, 1138 insertions(+), 135 deletions(-)
 create mode 100644 Documentation/ABI/obsolete/sysfs-class-typec
 create mode 100644 Documentation/ABI/testing/sysfs-bus-typec
 create mode 100644 Documentation/driver-api/usb/typec_bus.rst
 create mode 100644 drivers/usb/typec/bus.c
 create mode 100644 drivers/usb/typec/bus.h
 create mode 100644 include/linux/usb/typec_altmode.h

diff --git a/Documentation/ABI/obsolete/sysfs-class-typec b/Documentation/ABI/obsolete/sysfs-class-typec
new file mode 100644
index 000000000000..32623514ee87
--- /dev/null
+++ b/Documentation/ABI/obsolete/sysfs-class-typec
@@ -0,0 +1,48 @@
+These files are deprecated and will be removed. The same files are available
+under /sys/bus/typec (see Documentation/ABI/testing/sysfs-bus-typec).
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The SVID (Standard or Vendor ID) assigned by USB-IF for this
+		alternate mode.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Every supported mode will have its own directory. The name of
+		a mode will be "mode<index>" (for example mode1), where <index>
+		is the actual index to the mode VDO returned by Discover Modes
+		USB power delivery command.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows description of the mode. The description is optional for
+		the drivers, just like with the Billboard Devices.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows the VDO in hexadecimal returned by Discover Modes command
+		for this mode.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows if the mode is active or not. The attribute can be used
+		for entering/exiting the mode with partners and cable plugs, and
+		with the port alternate modes it can be used for disabling
+		support for specific alternate modes. Entering/exiting modes is
+		supported as synchronous operation so write(2) to the attribute
+		does not return until the enter/exit mode operation has
+		finished. The attribute is notified when the mode is
+		entered/exited so poll(2) on the attribute wakes up.
+		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
+
+		Valid values: yes, no
diff --git a/Documentation/ABI/testing/sysfs-bus-typec b/Documentation/ABI/testing/sysfs-bus-typec
new file mode 100644
index 000000000000..ead63f97d9a2
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-typec
@@ -0,0 +1,51 @@
+What:		/sys/bus/typec/devices/.../active
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows if the mode is active or not. The attribute can be used
+		for entering/exiting the mode. Entering/exiting modes is
+		supported as synchronous operation so write(2) to the attribute
+		does not return until the enter/exit mode operation has
+		finished. The attribute is notified when the mode is
+		entered/exited so poll(2) on the attribute wakes up.
+		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
+
+		Valid values are boolean.
+
+What:		/sys/bus/typec/devices/.../description
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows description of the mode. The description is optional for
+		the drivers, just like with the Billboard Devices.
+
+What:		/sys/bus/typec/devices/.../mode
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The index number of the mode returned by Discover Modes USB
+		Power Delivery command. Depending on the alternate mode, the
+		mode index may be significant.
+
+		With some alternate modes (SVIDs), the mode index is assigned
+		for specific functionality in the specification for that
+		alternate mode.
+
+		With other alternate modes, the mode index values are not
+		assigned, and can not be therefore used for identification. When
+		the mode index is not assigned, identifying the alternate mode
+		must be done with either mode VDO or the description.
+
+What:		/sys/bus/typec/devices/.../svid
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The Standard or Vendor ID (SVID) assigned by USB-IF for this
+		alternate mode.
+
+What:		/sys/bus/typec/devices/.../vdo
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows the VDO in hexadecimal returned by Discover Modes command
+		for this mode.
diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
index 5be552e255e9..d7647b258c3c 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -222,70 +222,12 @@ Description:
 		available. The value can be polled.
 
 
-Alternate Mode devices.
+USB Type-C port alternate mode devices.
 
-The alternate modes will have Standard or Vendor ID (SVID) assigned by USB-IF.
-The ports, partners and cable plugs can have alternate modes. A supported SVID
-will consist of a set of modes. Every SVID a port/partner/plug supports will
-have a device created for it, and every supported mode for a supported SVID will
-have its own directory under that device. Below <dev> refers to the device for
-the alternate mode.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		The SVID (Standard or Vendor ID) assigned by USB-IF for this
-		alternate mode.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Every supported mode will have its own directory. The name of
-		a mode will be "mode<index>" (for example mode1), where <index>
-		is the actual index to the mode VDO returned by Discover Modes
-		USB power delivery command.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Shows description of the mode. The description is optional for
-		the drivers, just like with the Billboard Devices.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Shows the VDO in hexadecimal returned by Discover Modes command
-		for this mode.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Shows if the mode is active or not. The attribute can be used
-		for entering/exiting the mode with partners and cable plugs, and
-		with the port alternate modes it can be used for disabling
-		support for specific alternate modes. Entering/exiting modes is
-		supported as synchronous operation so write(2) to the attribute
-		does not return until the enter/exit mode operation has
-		finished. The attribute is notified when the mode is
-		entered/exited so poll(2) on the attribute wakes up.
-		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
-
-		Valid values: yes, no
-
-What:		/sys/class/typec/<port>/<dev>/mode<index>/supported_roles
+What:		/sys/class/typec/<port>/<alt mode>/supported_roles
 Date:		April 2017
 Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
 Description:
 		Space separated list of the supported roles.
 
-		This attribute is available for the devices describing the
-		alternate modes a port supports, and it will not be exposed with
-		the devices presenting the alternate modes the partners or cable
-		plugs support.
-
 		Valid values: source, sink
diff --git a/Documentation/driver-api/usb/typec_bus.rst b/Documentation/driver-api/usb/typec_bus.rst
new file mode 100644
index 000000000000..ef3c049a8a7f
--- /dev/null
+++ b/Documentation/driver-api/usb/typec_bus.rst
@@ -0,0 +1,143 @@
+
+API for USB Type-C Alternate Mode drivers
+=========================================
+
+Introduction
+------------
+
+Alternate modes require communication with the partner using Vendor Defined
+Messages (VDM) as defined in USB Type-C and USB Power Delivery Specifications.
+The communication is SVID (Standard or Vendor ID) specific, i.e. specific for
+every alternate mode, so every alternate mode will need custom driver.
+
+USB Type-C bus allows binding a driver to the discovered partner alternate
+modes by using the SVID and the mode number.
+
+USB Type-C Connector Class provides a device for every alternate mode a port
+supports, and separate device for every alternate mode the partner supports.
+The drivers for the alternate modes are bind to the partner alternate mode
+devices, and the port alternate mode devices must be handled by the port
+drivers.
+
+When a new partner alternate mode device is registered, it is linked to the
+alternate mode device of the port that the partner is attached to, that has
+matching SVID and mode. Communication between the port driver and alternate mode
+driver will happen using the same API.
+
+The port alternate mode devices are used as a proxy between the partner and the
+alternate mode drivers, so the port drivers are only expected to pass the SVID
+specific commands from the alternate mode drivers to the partner, and from the
+partners to the alternate mode drivers. No direct SVID specific communication is
+needed from the port drivers, but the port drivers need to provide the operation
+callbacks for the port alternate mode devices, just like the alternate mode
+drivers need to provide them for the partner alternate mode devices.
+
+Usage:
+------
+
+General
+~~~~~~~
+
+By default, the alternate mode drivers are responsible for entering the mode.
+It is also possible to leave the decision about entering the mode to the user
+space (See Documentation/ABI/testing/sysfs-class-typec). Port drivers should not
+enter any modes on their own.
+
+The alternate mode drivers need to register their operation vector in their
+``->probe`` callback with :c:func:`typec_altmode_register_ops()`. They should
+be registered before the mode is entered using :c:func:`typec_altmode_enter()`.
+
+``->vdm`` is the most important callback in the vector. It will be used to
+deliver all the SVID specific commands from the partner to the alternate mode
+driver, and vise versa in case of port drivers. The drivers send the SVID
+specific commands to each other using :c:func:`typec_altmode_vmd()`.
+
+If the communication with the partner using the SVID specific commands results
+in need to re-configure the pins on the connector, the alternate mode driver
+needs to notify the bus using :c:func:`typec_altmode_notify()`. The driver
+passes the negotiated SVID specific pin configuration value to the function as
+parameter. The bus driver will then configure the mux behind the connector using
+that value as the state value for the mux, and also call blocking notification
+chain to notify the external drivers about the state of the connector that need
+to know it.
+
+NOTE: The SVID specific pin configuration values must always start from
+``TYPEC_STATE_MODAL``. USB Type-C specification defines two default states for
+the connector: ``TYPEC_STATE_USB`` and ``TYPEC_STATE_SAFE``. USB Type-C
+Specification also defines two Accessory modes, Audio and Debug:
+``TYPEC_STATE_AUDIO`` and ``TYPEC_STATE_DEBUG`` These values are reserved by the
+bus as the four first possible values for the state, and attempts to use them
+from the alternate mode drivers will result in failure. When the alternate mode
+is entered, the bus will put the connector into ``TYPEC_STATE_SAFE`` before
+sending Enter or Exit Mode command as defined in USB Type-C Specification, and
+also put the connector back to ``TYPEC_STATE_USB`` after the mode has been
+exited.
+
+An example of working definitions for SVID specific pin configurations would
+look like this:
+
+enum {
+	ALTMODEX_CONF_A = TYPEC_STATE_MODAL,
+	ALTMODEX_CONF_B,
+	...
+};
+
+Helper macro ``TYPEC_MODAL_STATE()`` can also be used:
+
+#define ALTMODEX_CONF_A = TYPEC_MODAL_STATE(0);
+#define ALTMODEX_CONF_B = TYPEC_MODAL_STATE(1);
+
+Notification chain
+~~~~~~~~~~~~~~~~~~
+
+The drivers for the components that the alternate modes are designed for need to
+get details regarding the results of the negotiation with the partner, and the
+pin configuration of the connector. In case of DisplayPort alternate mode for
+example, the GPU drivers will need to know those details. In case of
+Thunderbolt alternate mode, the thunderbolt drivers will need to know them, and
+so on.
+
+The notification chain is designed for this purpose. The drivers can register
+notifiers with :c:func:`typec_altmode_register_notifier()`.
+
+Cable plug alternate modes
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The alternate mode drivers are not bind to cable plug alternate mode devices,
+only to the partner alternate mode devices. If the alternate mode supports, or
+requires, a cable that responds to SOP Prime, and optionally SOP Double Prime
+messages, the driver for that alternate mode must request handle to the cable
+plug alternate modes using :c:func:`typec_altmode_get_plug()`, and taking over
+their control.
+
+Driver API
+----------
+
+Alternate mode driver registering/unregistering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_register_driver typec_altmode_unregister_driver
+
+Alternate mode driver operations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_register_ops typec_altmode_enter typec_altmode_exit typec_altmode_attention typec_altmode_vdm typec_altmode_notify
+
+API for the port drivers
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_match_altmode
+
+Cable Plug operations
+~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_get_plug typec_altmode_put_plug
+
+Notifications
+~~~~~~~~~~~~~
+.. kernel-doc:: drivers/usb/typec/class.c
+   :functions: typec_altmode_register_notifier typec_altmode_unregister_notifier
diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
index 1f599a6c30cc..5466c62c8e97 100644
--- a/drivers/usb/typec/Makefile
+++ b/drivers/usb/typec/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_TYPEC)		+= typec.o
-typec-y				:= class.o mux.o
+typec-y				:= class.o mux.o bus.o
 obj-$(CONFIG_TYPEC_TCPM)	+= tcpm.o
 obj-y				+= fusb302/
 obj-$(CONFIG_TYPEC_WCOVE)	+= typec_wcove.o
diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
new file mode 100644
index 000000000000..92944aaf3d6a
--- /dev/null
+++ b/drivers/usb/typec/bus.c
@@ -0,0 +1,421 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * Bus for USB Type-C Alternate Modes
+ *
+ * Copyright (C) 2018 Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ */
+
+#include "bus.h"
+
+/* -------------------------------------------------------------------------- */
+/* Common API */
+
+/**
+ * typec_altmode_notify - Communication between the OS and alternate mode driver
+ * @adev: Handle to the alternate mode
+ * @conf: Alternate mode specific configuration value
+ * @data: Alternate mode specific data
+ *
+ * The primary purpose for this function is to allow the alternate mode drivers
+ * to tell which pin configuration has been negotiated with the partner. That
+ * information will then be used for example to configure the muxes.
+ * Communication to the other direction is also possible, and low level device
+ * drivers can also send notifications to the alternate mode drivers. The actual
+ * communication will be specific for every SVID.
+ */
+int typec_altmode_notify(struct typec_altmode *adev,
+			 unsigned long conf, void *data)
+{
+	struct altmode *altmode;
+	struct altmode *partner;
+	int ret;
+
+	/*
+	 * All SVID specific configuration values must start from
+	 * TYPEC_STATE_MODAL. The first values are reserved for the pin states
+	 * defined in USB Type-C specification: TYPEC_STATE_USB and
+	 * TYPEC_STATE_SAFE. We'll follow this rule even with modes that do not
+	 * require pin reconfiguration for the sake of simplicity.
+	 */
+	if (conf < TYPEC_STATE_MODAL)
+		return -EINVAL;
+
+	if (!adev)
+		return 0;
+
+	altmode = to_altmode(adev);
+
+	if (!altmode->partner)
+		return -ENODEV;
+
+	ret = typec_set_mode(typec_altmode2port(adev), (int)conf);
+	if (ret)
+		return ret;
+
+	partner = altmode->partner;
+
+	blocking_notifier_call_chain(is_typec_port(adev->dev.parent) ?
+				     &altmode->nh : &partner->nh,
+				     conf, data);
+
+	if (partner->ops && partner->ops->notify)
+		return partner->ops->notify(&partner->adev, conf, data);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_notify);
+
+/**
+ * typec_altmode_enter - Enter Mode
+ * @adev: The alternate mode
+ *
+ * The alternate mode drivers use this function to enter mode. The port drivers
+ * use this to inform the alternate mode drivers that their mode has been
+ * entered successfully.
+ */
+int typec_altmode_enter(struct typec_altmode *adev)
+{
+	struct altmode *partner = to_altmode(adev)->partner;
+	struct typec_altmode *pdev = &partner->adev;
+	int ret;
+
+	if (is_typec_port(adev->dev.parent)) {
+		typec_altmode_update_active(pdev, pdev->mode, true);
+		sysfs_notify(&pdev->dev.kobj, NULL, "active");
+		goto enter_mode;
+	}
+
+	if (!pdev->active)
+		return -EPERM;
+
+	/* First moving to USB Safe State */
+	ret = typec_set_mode(typec_altmode2port(adev), TYPEC_STATE_SAFE);
+	if (ret)
+		return ret;
+
+	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
+
+enter_mode:
+	/* Enter Mode command */
+	if (partner->ops && partner->ops->enter)
+		partner->ops->enter(pdev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_enter);
+
+/**
+ * typec_altmode_enter - Exit Mode
+ * @adev: The alternate mode
+ *
+ * The alternate mode drivers use this function to exit mode. The port drivers
+ * can also inform the alternate mode drivers with this function that the mode
+ * was successfully exited.
+ */
+int typec_altmode_exit(struct typec_altmode *adev)
+{
+	struct altmode *partner = to_altmode(adev)->partner;
+	struct typec_port *port = typec_altmode2port(adev);
+	struct typec_altmode *pdev = &partner->adev;
+	int ret;
+
+	/* In case of port, just calling the driver and exiting */
+	if (is_typec_port(adev->dev.parent)) {
+		typec_altmode_update_active(pdev, pdev->mode, false);
+		sysfs_notify(&pdev->dev.kobj, NULL, "active");
+
+		if (partner->ops && partner->ops->exit)
+			partner->ops->exit(pdev);
+		return 0;
+	}
+
+	/* Moving to USB Safe State */
+	ret = typec_set_mode(port, TYPEC_STATE_SAFE);
+	if (ret)
+		return ret;
+
+	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
+
+	/* Exit Mode command */
+	if (partner->ops && partner->ops->exit)
+		partner->ops->exit(pdev);
+
+	/* Back to USB operation */
+	ret = typec_set_mode(port, TYPEC_STATE_USB);
+	if (ret)
+		return ret;
+
+	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_USB, NULL);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_exit);
+
+/**
+ * typec_altmode_attention - Attention command
+ * @adev: The alternate mode
+ * @vdo: VDO for the Attention command
+ *
+ * Notifies the partner of @adev about Attention command.
+ */
+void typec_altmode_attention(struct typec_altmode *adev, const u32 vdo)
+{
+	struct altmode *partner = to_altmode(adev)->partner;
+
+	if (partner && partner->ops && partner->ops->attention)
+		partner->ops->attention(&partner->adev, vdo);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_attention);
+
+/**
+ * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
+ * @adev: Alternate mode handle
+ * @header: VDM Header
+ * @vdo: Array of Vendor Defined Data Objects
+ * @count: Number of Data Objects
+ *
+ * The alternate mode drivers use this function for SVID specific communication
+ * with the partner. The port drivers use it to deliver the Structured VDMs
+ * received from the partners to the alternate mode drivers.
+ */
+int typec_altmode_vdm(struct typec_altmode *adev,
+		      const u32 header, const u32 *vdo, int count)
+{
+	struct altmode *altmode;
+	struct altmode *partner;
+
+	if (!adev)
+		return 0;
+
+	altmode = to_altmode(adev);
+
+	if (!altmode->partner)
+		return -ENODEV;
+
+	partner = altmode->partner;
+
+	if (partner->ops && partner->ops->vdm)
+		return partner->ops->vdm(&partner->adev, header, vdo, count);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_vdm);
+
+void typec_altmode_register_ops(struct typec_altmode *adev,
+				const struct typec_altmode_ops *ops)
+{
+	to_altmode(adev)->ops = ops;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_register_ops);
+
+/* -------------------------------------------------------------------------- */
+/* API for the alternate mode drivers */
+
+/**
+ * typec_altmode_get_plug - Find cable plug alternate mode
+ * @adev: Handle to partner alternate mode
+ * @index: Cable plug index
+ *
+ * Increment reference count for cable plug alternate mode device. Returns
+ * handle to the cable plug alternate mode, or NULL if none is found.
+ */
+struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
+					     int index)
+{
+	struct altmode *port = to_altmode(adev)->partner;
+
+	if (port->plug[index]) {
+		get_device(&port->plug[index]->adev.dev);
+		return &port->plug[index]->adev;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
+
+/**
+ * typec_altmode_get_plug - Decrement cable plug alternate mode reference count
+ * @plug: Handle to the cable plug alternate mode
+ */
+void typec_altmode_put_plug(struct typec_altmode *plug)
+{
+	if (plug)
+		put_device(&plug->dev);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_put_plug);
+
+int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
+				    struct module *module)
+{
+	if (!drv->probe)
+		return -EINVAL;
+
+	drv->driver.owner = module;
+	drv->driver.bus = &typec_bus;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(__typec_altmode_register_driver);
+
+void typec_altmode_unregister_driver(struct typec_altmode_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_unregister_driver);
+
+/* -------------------------------------------------------------------------- */
+/* API for the port drivers */
+
+bool typec_altmode_ufp_capable(struct typec_altmode *adev)
+{
+	struct altmode *altmode = to_altmode(adev);
+
+	if (!is_typec_port(adev->dev.parent))
+		return false;
+
+	return !(altmode->roles == TYPEC_PORT_DFP);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_ufp_capable);
+
+bool typec_altmode_dfp_capable(struct typec_altmode *adev)
+{
+	struct altmode *altmode = to_altmode(adev);
+
+	if (!is_typec_port(adev->dev.parent))
+		return false;
+
+	return !(altmode->roles == TYPEC_PORT_UFP);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_dfp_capable);
+
+/**
+ * typec_match_altmode - Match SVID to an array of alternate modes
+ * @altmodes: Array of alternate modes
+ * @n: Number of elements in the array, or -1 for NULL termiated arrays
+ * @svid: Standard or Vendor ID to match with
+ *
+ * Return pointer to an alternate mode with SVID mathing @svid, or NULL when no
+ * match is found.
+ */
+struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
+					  size_t n, u16 svid, u8 mode)
+{
+	int i;
+
+	for (i = 0; i < n; i++) {
+		if (!altmodes[i])
+			break;
+		if (altmodes[i]->svid == svid && altmodes[i]->mode == mode)
+			return altmodes[i];
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(typec_match_altmode);
+
+/* -------------------------------------------------------------------------- */
+
+static ssize_t
+description_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct typec_altmode *alt = to_typec_altmode(dev);
+
+	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
+}
+static DEVICE_ATTR_RO(description);
+
+static struct attribute *typec_attrs[] = {
+	&dev_attr_description.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(typec);
+
+static int typec_match(struct device *dev, struct device_driver *driver)
+{
+	struct typec_altmode_driver *drv = to_altmode_driver(driver);
+	struct typec_altmode *altmode = to_typec_altmode(dev);
+	const struct typec_device_id *id;
+
+	for (id = drv->id_table; id->svid; id++)
+		if ((id->svid == altmode->svid) &&
+		    (id->mode == TYPEC_ANY_MODE || id->mode == altmode->mode))
+			return 1;
+	return 0;
+}
+
+static int typec_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct typec_altmode *altmode = to_typec_altmode(dev);
+
+	if (add_uevent_var(env, "SVID=%04X", altmode->svid))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "MODE=%u", altmode->mode))
+		return -ENOMEM;
+
+	return add_uevent_var(env, "MODALIAS=typec:id%04Xm%02X",
+			      altmode->svid, altmode->mode);
+}
+
+static int typec_altmode_create_links(struct altmode *alt)
+{
+	struct device *port_dev = &alt->partner->adev.dev;
+	struct device *dev = &alt->adev.dev;
+	int err;
+
+	err = sysfs_create_link(&dev->kobj, &port_dev->kobj, "port");
+	if (err)
+		return err;
+
+	err = sysfs_create_link(&port_dev->kobj, &dev->kobj, "partner");
+	if (err)
+		sysfs_remove_link(&dev->kobj, "port");
+
+	return err;
+}
+
+static int typec_probe(struct device *dev)
+{
+	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct altmode *altmode = to_altmode(adev);
+
+	/* Fail if the port does not support the alternate mode */
+	if (!altmode->partner)
+		return -ENODEV;
+
+	if (typec_altmode_create_links(altmode))
+		dev_warn(dev, "failed to create symlinks\n");
+
+	return drv->probe(adev, altmode->partner->adev.vdo);
+}
+
+static int typec_remove(struct device *dev)
+{
+	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct altmode *altmode = to_altmode(adev);
+
+	if (!is_typec_port(adev->dev.parent)) {
+		sysfs_remove_link(&altmode->partner->adev.dev.kobj, "partner");
+		sysfs_remove_link(&adev->dev.kobj, "port");
+	}
+
+	if (drv->remove)
+		drv->remove(to_typec_altmode(dev));
+
+	if (adev->active)
+		typec_altmode_exit(adev);
+
+	return 0;
+}
+
+struct bus_type typec_bus = {
+	.name = "typec",
+	.dev_groups = typec_groups,
+	.match = typec_match,
+	.uevent = typec_uevent,
+	.probe = typec_probe,
+	.remove = typec_remove,
+};
diff --git a/drivers/usb/typec/bus.h b/drivers/usb/typec/bus.h
new file mode 100644
index 000000000000..38585363952f
--- /dev/null
+++ b/drivers/usb/typec/bus.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __USB_TYPEC_ALTMODE_H__
+#define __USB_TYPEC_ALTMODE_H__
+
+#include <linux/usb/typec.h>
+
+struct bus_type;
+
+struct altmode {
+	unsigned int			id;
+	struct typec_altmode		adev;
+
+	enum typec_port_data		roles;
+
+	struct attribute		*attrs[5];
+	char				group_name[6];
+	struct attribute_group		group;
+	const struct attribute_group	*groups[2];
+
+	struct altmode			*partner;
+	struct altmode			*plug[2];
+	const struct typec_altmode_ops	*ops;
+
+	struct blocking_notifier_head	nh;
+};
+
+#define to_altmode(d) container_of(d, struct altmode, adev)
+
+extern struct bus_type typec_bus;
+extern const struct device_type typec_altmode_dev_type;
+extern const struct device_type typec_port_dev_type;
+
+#define is_typec_altmode(_dev_) (_dev_->type == &typec_altmode_dev_type)
+#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
+
+#endif /* __USB_TYPEC_ALTMODE_H__ */
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 26eeab1491b7..33fffb853994 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -6,6 +6,7 @@
  * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
  */
 
+#include <linux/connection.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -13,25 +14,12 @@
 #include <linux/usb/typec.h>
 #include <linux/usb/typec_mux.h>
 
-struct typec_altmode {
-	struct device			dev;
-	u16				svid;
-	u8				mode;
-
-	u32				vdo;
-	char				*desc;
-	enum typec_port_type		roles;
-	unsigned int			active:1;
-
-	struct attribute		*attrs[5];
-	char				group_name[6];
-	struct attribute_group		group;
-	const struct attribute_group	*groups[2];
-};
+#include "bus.h"
 
 struct typec_plug {
 	struct device			dev;
 	enum typec_plug_index		index;
+	struct ida			mode_ids;
 };
 
 struct typec_cable {
@@ -46,11 +34,13 @@ struct typec_partner {
 	unsigned int			usb_pd:1;
 	struct usb_pd_identity		*identity;
 	enum typec_accessory		accessory;
+	struct ida			mode_ids;
 };
 
 struct typec_port {
 	unsigned int			id;
 	struct device			dev;
+	struct ida			mode_ids;
 
 	int				prefer_role;
 	enum typec_data_role		data_role;
@@ -71,17 +61,14 @@ struct typec_port {
 #define to_typec_plug(_dev_) container_of(_dev_, struct typec_plug, dev)
 #define to_typec_cable(_dev_) container_of(_dev_, struct typec_cable, dev)
 #define to_typec_partner(_dev_) container_of(_dev_, struct typec_partner, dev)
-#define to_altmode(_dev_) container_of(_dev_, struct typec_altmode, dev)
 
 static const struct device_type typec_partner_dev_type;
 static const struct device_type typec_cable_dev_type;
 static const struct device_type typec_plug_dev_type;
-static const struct device_type typec_port_dev_type;
 
 #define is_typec_partner(_dev_) (_dev_->type == &typec_partner_dev_type)
 #define is_typec_cable(_dev_) (_dev_->type == &typec_cable_dev_type)
 #define is_typec_plug(_dev_) (_dev_->type == &typec_plug_dev_type)
-#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
 
 static DEFINE_IDA(typec_index_ida);
 static struct class *typec_class;
@@ -163,27 +150,141 @@ static void typec_report_identity(struct device *dev)
 /* ------------------------------------------------------------------------- */
 /* Alternate Modes */
 
+static int altmode_match(struct device *dev, void *data)
+{
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct typec_device_id *id = data;
+
+	if (!is_typec_altmode(dev))
+		return 0;
+
+	return ((adev->svid == id->svid) && (adev->mode == id->mode));
+}
+
+static void typec_altmode_get_partner(struct altmode *altmode)
+{
+	struct typec_altmode *adev = &altmode->adev;
+	struct typec_device_id id = { adev->svid, adev->mode, };
+	struct typec_port *port = typec_altmode2port(adev);
+	struct altmode *partner;
+	struct device *dev;
+
+	dev = device_find_child(&port->dev, &id, altmode_match);
+	if (!dev)
+		return;
+
+	/* Bind the port alt mode to the partner/plug alt mode. */
+	partner = to_altmode(to_typec_altmode(dev));
+	altmode->partner = partner;
+
+	/* Bind the partner/plug alt mode to the port alt mode. */
+	if (is_typec_plug(adev->dev.parent)) {
+		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
+
+		partner->plug[plug->index] = altmode;
+	} else {
+		partner->partner = altmode;
+	}
+}
+
+static void typec_altmode_put_partner(struct altmode *altmode)
+{
+	struct altmode *partner = altmode->partner;
+	struct typec_altmode *adev;
+
+	if (!partner)
+		return;
+
+	adev = &partner->adev;
+
+	if (is_typec_plug(adev->dev.parent)) {
+		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
+
+		partner->plug[plug->index] = NULL;
+	} else {
+		partner->partner = NULL;
+	}
+	put_device(&adev->dev);
+}
+
+static int __typec_port_match(struct device *dev, const void *name)
+{
+	return !strcmp((const char *)name, dev_name(dev));
+}
+
+static void *typec_port_match(struct devcon *con, int ep, void *data)
+{
+	return class_find_device(typec_class, NULL, con->endpoint[ep],
+				 __typec_port_match);
+}
+
+struct typec_altmode *
+typec_altmode_register_notifier(struct device *dev, u16 svid, u8 mode,
+				struct notifier_block *nb)
+{
+	struct typec_device_id id = { svid, mode, };
+	struct device *altmode_dev;
+	struct device *port_dev;
+	struct altmode *altmode;
+	int ret;
+
+	/* Find the port linked to the caller */
+	port_dev = __device_find_connection(dev, NULL, NULL, typec_port_match);
+	if (!port_dev)
+		return ERR_PTR(-ENODEV);
+
+	/* Find the altmode with matching svid */
+	altmode_dev = device_find_child(port_dev, &id, altmode_match);
+
+	put_device(port_dev);
+
+	if (!altmode_dev)
+		return ERR_PTR(-ENODEV);
+
+	altmode = to_altmode(to_typec_altmode(altmode_dev));
+
+	/* Register notifier */
+	ret = blocking_notifier_chain_register(&altmode->nh, nb);
+	if (ret) {
+		put_device(altmode_dev);
+		return ERR_PTR(ret);
+	}
+
+	return &altmode->adev;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_register_notifier);
+
+void typec_altmode_unregister_notifier(struct typec_altmode *adev,
+				       struct notifier_block *nb)
+{
+	struct altmode *altmode = to_altmode(adev);
+
+	blocking_notifier_chain_unregister(&altmode->nh, nb);
+	put_device(&adev->dev);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_unregister_notifier);
+
 /**
  * typec_altmode_update_active - Report Enter/Exit mode
- * @alt: Handle to the alternate mode
+ * @adev: Handle to the alternate mode
  * @mode: Mode index
  * @active: True when the mode has been entered
  *
  * If a partner or cable plug executes Enter/Exit Mode command successfully, the
  * drivers use this routine to report the updated state of the mode.
  */
-void typec_altmode_update_active(struct typec_altmode *alt, int mode,
+void typec_altmode_update_active(struct typec_altmode *adev, int mode,
 				 bool active)
 {
 	char dir[6];
 
-	if (alt->active == active)
+	if (adev->active == active)
 		return;
 
-	alt->active = active;
+	adev->active = active;
 	snprintf(dir, sizeof(dir), "mode%d", mode);
-	sysfs_notify(&alt->dev.kobj, dir, "active");
-	kobject_uevent(&alt->dev.kobj, KOBJ_CHANGE);
+	sysfs_notify(&adev->dev.kobj, dir, "active");
+	kobject_uevent(&adev->dev.kobj, KOBJ_CHANGE);
 }
 EXPORT_SYMBOL_GPL(typec_altmode_update_active);
 
@@ -210,7 +311,7 @@ EXPORT_SYMBOL_GPL(typec_altmode2port);
 static ssize_t
 vdo_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *alt = to_typec_altmode(dev);
 
 	return sprintf(buf, "0x%08x\n", alt->vdo);
 }
@@ -219,7 +320,7 @@ static DEVICE_ATTR_RO(vdo);
 static ssize_t
 description_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *alt = to_typec_altmode(dev);
 
 	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
 }
@@ -228,28 +329,46 @@ static DEVICE_ATTR_RO(description);
 static ssize_t
 active_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *alt = to_typec_altmode(dev);
 
 	return sprintf(buf, "%s\n", alt->active ? "yes" : "no");
 }
 
-static ssize_t
-active_store(struct device *dev, struct device_attribute *attr,
-			   const char *buf, size_t size)
+static ssize_t active_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t size)
 {
-	struct typec_altmode *alt = to_altmode(dev);
-	struct typec_port *port = typec_altmode2port(alt);
-	bool activate;
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct typec_port *port = typec_altmode2port(adev);
+	struct altmode *altmode = to_altmode(adev);
+	bool enter;
 	int ret;
 
 	if (!port->cap->activate_mode)
 		return -EOPNOTSUPP;
 
-	ret = kstrtobool(buf, &activate);
+	ret = kstrtobool(buf, &enter);
 	if (ret)
 		return ret;
 
-	ret = port->cap->activate_mode(port->cap, alt->mode, activate);
+	if (adev->active == enter)
+		return size;
+
+	if (is_typec_port(adev->dev.parent)) {
+		typec_altmode_update_active(adev, adev->mode, enter);
+		sysfs_notify(&adev->dev.kobj, NULL, "active");
+
+		if (!altmode->partner)
+			return size;
+	} else {
+		adev = &altmode->partner->adev;
+
+		if (!adev->active) {
+			dev_warn(dev, "port has the mode disabled\n");
+			return -EPERM;
+		}
+	}
+
+	ret = port->cap->activate_mode(adev, enter);
 	if (ret)
 		return ret;
 
@@ -261,7 +380,7 @@ static ssize_t
 supported_roles_show(struct device *dev, struct device_attribute *attr,
 		     char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct altmode *alt = to_altmode(to_typec_altmode(dev));
 	ssize_t ret;
 
 	switch (alt->roles) {
@@ -280,29 +399,72 @@ supported_roles_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(supported_roles);
 
-static void typec_altmode_release(struct device *dev)
+static ssize_t
+mode_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *adev = to_typec_altmode(dev);
 
-	kfree(alt);
+	return sprintf(buf, "%u\n", adev->mode);
 }
+static DEVICE_ATTR_RO(mode);
 
-static ssize_t svid_show(struct device *dev, struct device_attribute *attr,
-			 char *buf)
+static ssize_t
+svid_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *adev = to_typec_altmode(dev);
 
-	return sprintf(buf, "%04x\n", alt->svid);
+	return sprintf(buf, "%04x\n", adev->svid);
 }
 static DEVICE_ATTR_RO(svid);
 
 static struct attribute *typec_altmode_attrs[] = {
+	&dev_attr_active.attr,
+	&dev_attr_mode.attr,
 	&dev_attr_svid.attr,
+	&dev_attr_vdo.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(typec_altmode);
 
-static const struct device_type typec_altmode_dev_type = {
+static int altmode_id_get(struct device *dev)
+{
+	struct ida *ids;
+
+	if (is_typec_partner(dev))
+		ids = &to_typec_partner(dev)->mode_ids;
+	else if (is_typec_plug(dev))
+		ids = &to_typec_plug(dev)->mode_ids;
+	else
+		ids = &to_typec_port(dev)->mode_ids;
+
+	return ida_simple_get(ids, 0, 0, GFP_KERNEL);
+}
+
+static void altmode_id_remove(struct device *dev, int id)
+{
+	struct ida *ids;
+
+	if (is_typec_partner(dev))
+		ids = &to_typec_partner(dev)->mode_ids;
+	else if (is_typec_plug(dev))
+		ids = &to_typec_plug(dev)->mode_ids;
+	else
+		ids = &to_typec_port(dev)->mode_ids;
+
+	ida_simple_remove(ids, id);
+}
+
+static void typec_altmode_release(struct device *dev)
+{
+	struct altmode *alt = to_altmode(to_typec_altmode(dev));
+
+	typec_altmode_put_partner(alt);
+
+	altmode_id_remove(alt->adev.dev.parent, alt->id);
+	kfree(alt);
+}
+
+const struct device_type typec_altmode_dev_type = {
 	.name = "typec_alternate_mode",
 	.groups = typec_altmode_groups,
 	.release = typec_altmode_release,
@@ -312,58 +474,72 @@ static struct typec_altmode *
 typec_register_altmode(struct device *parent,
 		       const struct typec_altmode_desc *desc)
 {
-	struct typec_altmode *alt;
+	unsigned int id = altmode_id_get(parent);
+	bool is_port = is_typec_port(parent);
+	struct altmode *alt;
 	int ret;
 
 	alt = kzalloc(sizeof(*alt), GFP_KERNEL);
 	if (!alt)
 		return ERR_PTR(-ENOMEM);
 
-	alt->svid = desc->svid;
-	alt->mode = desc->mode;
-	alt->vdo = desc->vdo;
+	alt->adev.svid = desc->svid;
+	alt->adev.mode = desc->mode;
+	alt->adev.vdo = desc->vdo;
 	alt->roles = desc->roles;
+	alt->id = id;
 
 	alt->attrs[0] = &dev_attr_vdo.attr;
 	alt->attrs[1] = &dev_attr_description.attr;
 	alt->attrs[2] = &dev_attr_active.attr;
 
-	if (is_typec_port(parent))
+	if (is_port) {
 		alt->attrs[3] = &dev_attr_supported_roles.attr;
+		alt->adev.active = true; /* Enabled by default */
+	}
 
 	sprintf(alt->group_name, "mode%d", desc->mode);
 	alt->group.name = alt->group_name;
 	alt->group.attrs = alt->attrs;
 	alt->groups[0] = &alt->group;
 
-	alt->dev.parent = parent;
-	alt->dev.groups = alt->groups;
-	alt->dev.type = &typec_altmode_dev_type;
-	dev_set_name(&alt->dev, "%s-%04x:%u", dev_name(parent),
-		     alt->svid, alt->mode);
+	alt->adev.dev.parent = parent;
+	alt->adev.dev.groups = alt->groups;
+	alt->adev.dev.type = &typec_altmode_dev_type;
+	dev_set_name(&alt->adev.dev, "%s.%u", dev_name(parent), id);
+
+	/* Link partners and plugs with the ports */
+	if (is_port)
+		BLOCKING_INIT_NOTIFIER_HEAD(&alt->nh);
+	else
+		typec_altmode_get_partner(alt);
 
-	ret = device_register(&alt->dev);
+	/* The partners are bind to drivers */
+	if (is_typec_partner(parent))
+		alt->adev.dev.bus = &typec_bus;
+
+	ret = device_register(&alt->adev.dev);
 	if (ret) {
 		dev_err(parent, "failed to register alternate mode (%d)\n",
 			ret);
-		put_device(&alt->dev);
+		put_device(&alt->adev.dev);
 		return ERR_PTR(ret);
 	}
 
-	return alt;
+	return &alt->adev;
 }
 
 /**
  * typec_unregister_altmode - Unregister Alternate Mode
- * @alt: The alternate mode to be unregistered
+ * @adev: The alternate mode to be unregistered
  *
  * Unregister device created with typec_partner_register_altmode(),
  * typec_plug_register_altmode() or typec_port_register_altmode().
  */
-void typec_unregister_altmode(struct typec_altmode *alt)
+void typec_unregister_altmode(struct typec_altmode *adev)
 {
-	if (!IS_ERR_OR_NULL(alt))
-		device_unregister(&alt->dev);
+	if (!IS_ERR_OR_NULL(adev))
+		device_unregister(&adev->dev);
 }
 EXPORT_SYMBOL_GPL(typec_unregister_altmode);
 
@@ -401,6 +577,7 @@ static void typec_partner_release(struct device *dev)
 {
 	struct typec_partner *partner = to_typec_partner(dev);
 
+	ida_destroy(&partner->mode_ids);
 	kfree(partner);
 }
 
@@ -466,6 +643,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
 	if (!partner)
 		return ERR_PTR(-ENOMEM);
 
+	ida_init(&partner->mode_ids);
 	partner->usb_pd = desc->usb_pd;
 	partner->accessory = desc->accessory;
 
@@ -514,6 +692,7 @@ static void typec_plug_release(struct device *dev)
 {
 	struct typec_plug *plug = to_typec_plug(dev);
 
+	ida_destroy(&plug->mode_ids);
 	kfree(plug);
 }
 
@@ -566,6 +745,7 @@ struct typec_plug *typec_register_plug(struct typec_cable *cable,
 
 	sprintf(name, "plug%d", desc->index);
 
+	ida_init(&plug->mode_ids);
 	plug->index = desc->index;
 	plug->dev.class = typec_class;
 	plug->dev.parent = &cable->dev;
@@ -1080,12 +1260,13 @@ static void typec_release(struct device *dev)
 	struct typec_port *port = to_typec_port(dev);
 
 	ida_simple_remove(&typec_index_ida, port->id);
+	ida_destroy(&port->mode_ids);
 	typec_switch_put(port->sw);
 	typec_mux_put(port->mux);
 	kfree(port);
 }
 
-static const struct device_type typec_port_dev_type = {
+const struct device_type typec_port_dev_type = {
 	.name = "typec_port",
 	.groups = typec_groups,
 	.uevent = typec_uevent,
@@ -1238,6 +1419,8 @@ EXPORT_SYMBOL_GPL(typec_set_mode);
  * typec_port_register_altmode - Register USB Type-C Port Alternate Mode
  * @port: USB Type-C Port that supports the alternate mode
  * @desc: Description of the alternate mode
+ * @ops: Port specific operations for the alternate mode
+ * @drvdata: Private pointer to driver specific info
  *
  * This routine is used to register an alternate mode that @port is capable of
  * supporting.
@@ -1322,10 +1505,12 @@ struct typec_port *typec_register_port(struct device *parent,
 		break;
 	}
 
+	ida_init(&port->mode_ids);
+	mutex_init(&port->port_type_lock);
+
 	port->id = id;
 	port->cap = cap;
 	port->port_type = cap->type;
-	mutex_init(&port->port_type_lock);
 	port->prefer_role = cap->prefer_role;
 
 	port->dev.class = typec_class;
@@ -1369,8 +1554,19 @@ EXPORT_SYMBOL_GPL(typec_unregister_port);
 
 static int __init typec_init(void)
 {
+	int ret;
+
+	ret = bus_register(&typec_bus);
+	if (ret)
+		return ret;
+
 	typec_class = class_create(THIS_MODULE, "typec");
-	return PTR_ERR_OR_ZERO(typec_class);
+	if (IS_ERR(typec_class)) {
+		bus_unregister(&typec_bus);
+		return PTR_ERR(typec_class);
+	}
+
+	return 0;
 }
 subsys_initcall(typec_init);
 
@@ -1378,6 +1574,7 @@ static void __exit typec_exit(void)
 {
 	class_destroy(typec_class);
 	ida_destroy(&typec_index_ida);
+	bus_unregister(&typec_bus);
 }
 module_exit(typec_exit);
 
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 48fb2b43c35a..17c1a912f524 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -733,4 +733,19 @@ struct tb_service_id {
 #define TBSVC_MATCH_PROTOCOL_VERSION	0x0004
 #define TBSVC_MATCH_PROTOCOL_REVISION	0x0008
 
+/* USB Type-C Alternate Modes */
+
+#define TYPEC_ANY_MODE	0x7
+
+/**
+ * struct typec_device_id - USB Type-C alternate mode identifiers
+ * @svid: Standard or Vendor ID
+ * @mode: Mode index
+ */
+struct typec_device_id {
+	__u16 svid;
+	__u8 mode;
+	kernel_ulong_t driver_data;
+};
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 278b6b42c7ea..a19aa3db4272 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -4,16 +4,13 @@
 #define __LINUX_USB_TYPEC_H
 
 #include <linux/types.h>
-
-/* XXX: Once we have a header for USB Power Delivery, this belongs there */
-#define ALTMODE_MAX_MODES	6
+#include <linux/usb/typec_altmode.h>
 
 /* USB Type-C Specification releases */
 #define USB_TYPEC_REV_1_0	0x100 /* 1.0 */
 #define USB_TYPEC_REV_1_1	0x110 /* 1.1 */
 #define USB_TYPEC_REV_1_2	0x120 /* 1.2 */
 
-struct typec_altmode;
 struct typec_partner;
 struct typec_cable;
 struct typec_plug;
@@ -107,7 +104,7 @@ struct typec_altmode_desc {
 	u8			mode;
 	u32			vdo;
 	/* Only used with ports */
-	enum typec_port_type	roles;
+	enum typec_port_data	roles;
 };
 
 struct typec_altmode
@@ -118,7 +115,8 @@ struct typec_altmode
 			     const struct typec_altmode_desc *desc);
 struct typec_altmode
 *typec_port_register_altmode(struct typec_port *port,
-			     const struct typec_altmode_desc *desc);
+			    const struct typec_altmode_desc *desc);
+
 void typec_unregister_altmode(struct typec_altmode *altmode);
 
 struct typec_port *typec_altmode2port(struct typec_altmode *alt);
@@ -213,12 +211,10 @@ struct typec_capability {
 				  enum typec_role);
 	int		(*vconn_set)(const struct typec_capability *,
 				     enum typec_role);
-
-	int		(*activate_mode)(const struct typec_capability *,
-					 int mode, int activate);
 	int		(*port_type_set)(const struct typec_capability *,
-					enum typec_port_type);
+					 enum typec_port_type);
 
+	int		(*activate_mode)(struct typec_altmode *alt, int active);
 };
 
 /* Specific to try_role(). Indicates the user want's to clear the preference. */
diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
new file mode 100644
index 000000000000..bc765352a3c8
--- /dev/null
+++ b/include/linux/usb/typec_altmode.h
@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __USB_TYPEC_ALTMODE_H
+#define __USB_TYPEC_ALTMODE_H
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+
+#define MODE_DISCOVERY_MAX	6
+
+/**
+ * struct typec_altmode - USB Type-C alternate mode device
+ * @dev: Driver model's view of this device
+ * @svid: Standard or Vendor ID (SVID) of the alternate mode
+ * @mode: Index of the Mode
+ * @vdo: VDO returned by Discover Modes USB PD command
+ * @desc: Optional human readable description of the mode
+ * @active: Tells has the mode been entered or not
+ */
+struct typec_altmode {
+	struct device		dev;
+	u16			svid;
+	int			mode;
+	u32			vdo;
+	char			*desc;
+	bool			active;
+} __packed;
+
+#define to_typec_altmode(d) container_of(d, struct typec_altmode, dev)
+
+static inline void typec_altmode_set_drvdata(struct typec_altmode *altmode,
+					     void *data)
+{
+	dev_set_drvdata(&altmode->dev, data);
+}
+
+static inline void *typec_altmode_get_drvdata(struct typec_altmode *altmode)
+{
+	return dev_get_drvdata(&altmode->dev);
+}
+
+/**
+ * struct typec_altmode_ops - Alternate mode specific operations vector
+ * @enter: Operations to be executed with Enter Mode Command
+ * @exit: Operations to be executed with Exit Mode Command
+ * @attention: Callback for Attention Command
+ * @vdm: Callback for SVID specific commands
+ * @notify: Communication channel for platform and the alternate mode
+ */
+struct typec_altmode_ops {
+	void (*enter)(struct typec_altmode *altmode);
+	void (*exit)(struct typec_altmode *altmode);
+	void (*attention)(struct typec_altmode *altmode, const u32 vdo);
+	int (*vdm)(struct typec_altmode *altmode, const u32 hdr,
+		   const u32 *vdo, int cnt);
+	int (*notify)(struct typec_altmode *altmode, unsigned long conf,
+		      void *data);
+};
+
+void typec_altmode_register_ops(struct typec_altmode *altmode,
+				const struct typec_altmode_ops *ops);
+
+int typec_altmode_enter(struct typec_altmode *altmode);
+int typec_altmode_exit(struct typec_altmode *altmode);
+void typec_altmode_attention(struct typec_altmode *altmode, const u32 vdo);
+int typec_altmode_vdm(struct typec_altmode *altmode,
+		      const u32 header, const u32 *vdo, int count);
+int typec_altmode_notify(struct typec_altmode *altmode, unsigned long conf,
+			 void *data);
+
+/* Return values for type_altmode_vdm() */
+#define VDM_DONE		0 /* Don't care */
+#define VDM_OK			1 /* Suits me */
+
+/*
+ * These are the pin states (USB, Safe and Alt Mode) and accessory modes (Audio
+ * and Debug) defined in USB Type-C Specification. SVID specific pin states are
+ * expected to follow and start from the value TYPEC_STATE_MODAL.
+ *
+ * Port drivers should use TYPEC_STATE_AUDIO and TYPEC_STATE_DEBUG as the
+ * operation value for typec_set_mode() when accessory modes are in use.
+ *
+ * NOTE: typec_altmode_notify() does not accept values smaller then
+ * TYPEC_STATE_MODAL. USB Type-C bus will follow USB Type-C Specification with
+ * TYPEC_STATE_USB and TYPEC_STATE_SAFE.
+ */
+enum {
+	TYPEC_STATE_USB,	/* USB Operation */
+	TYPEC_STATE_AUDIO,	/* Audio Accessory */
+	TYPEC_STATE_DEBUG,	/* Debug Accessory */
+	TYPEC_STATE_SAFE,	/* USB Safe State */
+	TYPEC_STATE_MODAL,	/* Alternate Modes */
+};
+
+#define TYPEC_MODAL_STATE(_state_)	((_state_) + TYPEC_STATE_MODAL)
+
+struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *altmode,
+					     int index);
+void typec_altmode_put_plug(struct typec_altmode *plug);
+
+bool typec_altmode_ufp_capable(struct typec_altmode *altmode);
+bool typec_altmode_dfp_capable(struct typec_altmode *altmode);
+struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
+					  size_t n, u16 svid, u8 mode);
+
+/**
+ * struct typec_altmode_driver - USB Type-C alternate mode device driver
+ * @id_table: Null terminated array of SVIDs
+ * @probe: Callback for device binding
+ * @remove: Callback for device unbinding
+ * @driver: Device driver model driver
+ *
+ * These drivers will be bind to the partner alternate mode devices. They will
+ * handle all SVID specific communication.
+ */
+struct typec_altmode_driver {
+	const struct typec_device_id *id_table;
+	int (*probe)(struct typec_altmode *altmode, u32 port_vdo);
+	void (*remove)(struct typec_altmode *altmode);
+	struct device_driver driver;
+};
+
+#define to_altmode_driver(d) container_of(d, struct typec_altmode_driver, \
+					  driver)
+
+#define typec_altmode_register_driver(drv) \
+		__typec_altmode_register_driver(drv, THIS_MODULE)
+int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
+				    struct module *module);
+void typec_altmode_unregister_driver(struct typec_altmode_driver *drv);
+
+#define module_typec_altmode_driver(__typec_altmode_driver) \
+	module_driver(__typec_altmode_driver, typec_altmode_register_driver, \
+		      typec_altmode_unregister_driver)
+
+#endif /* __USB_TYPEC_ALTMODE_H */
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index 9fad6afe4c41..c48c7f56ae64 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -218,5 +218,9 @@ int main(void)
 	DEVID_FIELD(tb_service_id, protocol_version);
 	DEVID_FIELD(tb_service_id, protocol_revision);
 
+	DEVID(typec_device_id);
+	DEVID_FIELD(typec_device_id, svid);
+	DEVID_FIELD(typec_device_id, mode);
+
 	return 0;
 }
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index b9beeaa4695b..a8afba836409 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1341,6 +1341,19 @@ static int do_tbsvc_entry(const char *filename, void *symval, char *alias)
 }
 ADD_TO_DEVTABLE("tbsvc", tb_service_id, do_tbsvc_entry);
 
+/* Looks like: typec:idNmN */
+static int do_typec_entry(const char *filename, void *symval, char *alias)
+{
+	DEF_FIELD(symval, typec_device_id, svid);
+	DEF_FIELD(symval, typec_device_id, mode);
+
+	sprintf(alias, "typec:id%04X", svid);
+	ADD(alias, "m", mode != TYPEC_ANY_MODE, mode);
+
+	return 1;
+}
+ADD_TO_DEVTABLE("typec", typec_device_id, do_typec_entry);
+
 /* Does namelen bytes of name exactly match the symbol? */
 static bool sym_is(const char *name, unsigned namelen, const char *symbol)
 {
-- 
2.16.1

[RFC,v2,2/3] usb: typec: Bus type for alternate modes

[Heikki Krogerus]

Introducing a simple bus for the alternate modes. Bus allows
binding drivers to the discovered alternate modes the
partners support.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 Documentation/ABI/obsolete/sysfs-class-typec |  48 +++
 Documentation/ABI/testing/sysfs-bus-typec    |  51 ++++
 Documentation/ABI/testing/sysfs-class-typec  |  62 +---
 Documentation/driver-api/usb/typec_bus.rst   | 143 +++++++++
 drivers/usb/typec/Makefile                   |   2 +-
 drivers/usb/typec/bus.c                      | 421 +++++++++++++++++++++++++++
 drivers/usb/typec/bus.h                      |  37 +++
 drivers/usb/typec/class.c                    | 325 +++++++++++++++++----
 include/linux/mod_devicetable.h              |  15 +
 include/linux/usb/typec.h                    |  16 +-
 include/linux/usb/typec_altmode.h            | 136 +++++++++
 scripts/mod/devicetable-offsets.c            |   4 +
 scripts/mod/file2alias.c                     |  13 +
 13 files changed, 1138 insertions(+), 135 deletions(-)
 create mode 100644 Documentation/ABI/obsolete/sysfs-class-typec
 create mode 100644 Documentation/ABI/testing/sysfs-bus-typec
 create mode 100644 Documentation/driver-api/usb/typec_bus.rst
 create mode 100644 drivers/usb/typec/bus.c
 create mode 100644 drivers/usb/typec/bus.h
 create mode 100644 include/linux/usb/typec_altmode.h

diff --git a/Documentation/ABI/obsolete/sysfs-class-typec b/Documentation/ABI/obsolete/sysfs-class-typec
new file mode 100644
index 000000000000..32623514ee87
--- /dev/null
+++ b/Documentation/ABI/obsolete/sysfs-class-typec
@@ -0,0 +1,48 @@
+These files are deprecated and will be removed. The same files are available
+under /sys/bus/typec (see Documentation/ABI/testing/sysfs-bus-typec).
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The SVID (Standard or Vendor ID) assigned by USB-IF for this
+		alternate mode.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Every supported mode will have its own directory. The name of
+		a mode will be "mode<index>" (for example mode1), where <index>
+		is the actual index to the mode VDO returned by Discover Modes
+		USB power delivery command.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows description of the mode. The description is optional for
+		the drivers, just like with the Billboard Devices.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows the VDO in hexadecimal returned by Discover Modes command
+		for this mode.
+
+What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
+Date:		April 2017
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows if the mode is active or not. The attribute can be used
+		for entering/exiting the mode with partners and cable plugs, and
+		with the port alternate modes it can be used for disabling
+		support for specific alternate modes. Entering/exiting modes is
+		supported as synchronous operation so write(2) to the attribute
+		does not return until the enter/exit mode operation has
+		finished. The attribute is notified when the mode is
+		entered/exited so poll(2) on the attribute wakes up.
+		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
+
+		Valid values: yes, no
diff --git a/Documentation/ABI/testing/sysfs-bus-typec b/Documentation/ABI/testing/sysfs-bus-typec
new file mode 100644
index 000000000000..ead63f97d9a2
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-typec
@@ -0,0 +1,51 @@
+What:		/sys/bus/typec/devices/.../active
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows if the mode is active or not. The attribute can be used
+		for entering/exiting the mode. Entering/exiting modes is
+		supported as synchronous operation so write(2) to the attribute
+		does not return until the enter/exit mode operation has
+		finished. The attribute is notified when the mode is
+		entered/exited so poll(2) on the attribute wakes up.
+		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
+
+		Valid values are boolean.
+
+What:		/sys/bus/typec/devices/.../description
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows description of the mode. The description is optional for
+		the drivers, just like with the Billboard Devices.
+
+What:		/sys/bus/typec/devices/.../mode
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The index number of the mode returned by Discover Modes USB
+		Power Delivery command. Depending on the alternate mode, the
+		mode index may be significant.
+
+		With some alternate modes (SVIDs), the mode index is assigned
+		for specific functionality in the specification for that
+		alternate mode.
+
+		With other alternate modes, the mode index values are not
+		assigned, and can not be therefore used for identification. When
+		the mode index is not assigned, identifying the alternate mode
+		must be done with either mode VDO or the description.
+
+What:		/sys/bus/typec/devices/.../svid
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		The Standard or Vendor ID (SVID) assigned by USB-IF for this
+		alternate mode.
+
+What:		/sys/bus/typec/devices/.../vdo
+Date:		April 2018
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:
+		Shows the VDO in hexadecimal returned by Discover Modes command
+		for this mode.
diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
index 5be552e255e9..d7647b258c3c 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -222,70 +222,12 @@ Description:
 		available. The value can be polled.
 
 
-Alternate Mode devices.
+USB Type-C port alternate mode devices.
 
-The alternate modes will have Standard or Vendor ID (SVID) assigned by USB-IF.
-The ports, partners and cable plugs can have alternate modes. A supported SVID
-will consist of a set of modes. Every SVID a port/partner/plug supports will
-have a device created for it, and every supported mode for a supported SVID will
-have its own directory under that device. Below <dev> refers to the device for
-the alternate mode.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		The SVID (Standard or Vendor ID) assigned by USB-IF for this
-		alternate mode.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Every supported mode will have its own directory. The name of
-		a mode will be "mode<index>" (for example mode1), where <index>
-		is the actual index to the mode VDO returned by Discover Modes
-		USB power delivery command.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Shows description of the mode. The description is optional for
-		the drivers, just like with the Billboard Devices.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Shows the VDO in hexadecimal returned by Discover Modes command
-		for this mode.
-
-What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
-Date:		April 2017
-Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
-Description:
-		Shows if the mode is active or not. The attribute can be used
-		for entering/exiting the mode with partners and cable plugs, and
-		with the port alternate modes it can be used for disabling
-		support for specific alternate modes. Entering/exiting modes is
-		supported as synchronous operation so write(2) to the attribute
-		does not return until the enter/exit mode operation has
-		finished. The attribute is notified when the mode is
-		entered/exited so poll(2) on the attribute wakes up.
-		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
-
-		Valid values: yes, no
-
-What:		/sys/class/typec/<port>/<dev>/mode<index>/supported_roles
+What:		/sys/class/typec/<port>/<alt mode>/supported_roles
 Date:		April 2017
 Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
 Description:
 		Space separated list of the supported roles.
 
-		This attribute is available for the devices describing the
-		alternate modes a port supports, and it will not be exposed with
-		the devices presenting the alternate modes the partners or cable
-		plugs support.
-
 		Valid values: source, sink
diff --git a/Documentation/driver-api/usb/typec_bus.rst b/Documentation/driver-api/usb/typec_bus.rst
new file mode 100644
index 000000000000..ef3c049a8a7f
--- /dev/null
+++ b/Documentation/driver-api/usb/typec_bus.rst
@@ -0,0 +1,143 @@
+
+API for USB Type-C Alternate Mode drivers
+=========================================
+
+Introduction
+------------
+
+Alternate modes require communication with the partner using Vendor Defined
+Messages (VDM) as defined in USB Type-C and USB Power Delivery Specifications.
+The communication is SVID (Standard or Vendor ID) specific, i.e. specific for
+every alternate mode, so every alternate mode will need custom driver.
+
+USB Type-C bus allows binding a driver to the discovered partner alternate
+modes by using the SVID and the mode number.
+
+USB Type-C Connector Class provides a device for every alternate mode a port
+supports, and separate device for every alternate mode the partner supports.
+The drivers for the alternate modes are bind to the partner alternate mode
+devices, and the port alternate mode devices must be handled by the port
+drivers.
+
+When a new partner alternate mode device is registered, it is linked to the
+alternate mode device of the port that the partner is attached to, that has
+matching SVID and mode. Communication between the port driver and alternate mode
+driver will happen using the same API.
+
+The port alternate mode devices are used as a proxy between the partner and the
+alternate mode drivers, so the port drivers are only expected to pass the SVID
+specific commands from the alternate mode drivers to the partner, and from the
+partners to the alternate mode drivers. No direct SVID specific communication is
+needed from the port drivers, but the port drivers need to provide the operation
+callbacks for the port alternate mode devices, just like the alternate mode
+drivers need to provide them for the partner alternate mode devices.
+
+Usage:
+------
+
+General
+~~~~~~~
+
+By default, the alternate mode drivers are responsible for entering the mode.
+It is also possible to leave the decision about entering the mode to the user
+space (See Documentation/ABI/testing/sysfs-class-typec). Port drivers should not
+enter any modes on their own.
+
+The alternate mode drivers need to register their operation vector in their
+``->probe`` callback with :c:func:`typec_altmode_register_ops()`. They should
+be registered before the mode is entered using :c:func:`typec_altmode_enter()`.
+
+``->vdm`` is the most important callback in the vector. It will be used to
+deliver all the SVID specific commands from the partner to the alternate mode
+driver, and vise versa in case of port drivers. The drivers send the SVID
+specific commands to each other using :c:func:`typec_altmode_vmd()`.
+
+If the communication with the partner using the SVID specific commands results
+in need to re-configure the pins on the connector, the alternate mode driver
+needs to notify the bus using :c:func:`typec_altmode_notify()`. The driver
+passes the negotiated SVID specific pin configuration value to the function as
+parameter. The bus driver will then configure the mux behind the connector using
+that value as the state value for the mux, and also call blocking notification
+chain to notify the external drivers about the state of the connector that need
+to know it.
+
+NOTE: The SVID specific pin configuration values must always start from
+``TYPEC_STATE_MODAL``. USB Type-C specification defines two default states for
+the connector: ``TYPEC_STATE_USB`` and ``TYPEC_STATE_SAFE``. USB Type-C
+Specification also defines two Accessory modes, Audio and Debug:
+``TYPEC_STATE_AUDIO`` and ``TYPEC_STATE_DEBUG`` These values are reserved by the
+bus as the four first possible values for the state, and attempts to use them
+from the alternate mode drivers will result in failure. When the alternate mode
+is entered, the bus will put the connector into ``TYPEC_STATE_SAFE`` before
+sending Enter or Exit Mode command as defined in USB Type-C Specification, and
+also put the connector back to ``TYPEC_STATE_USB`` after the mode has been
+exited.
+
+An example of working definitions for SVID specific pin configurations would
+look like this:
+
+enum {
+	ALTMODEX_CONF_A = TYPEC_STATE_MODAL,
+	ALTMODEX_CONF_B,
+	...
+};
+
+Helper macro ``TYPEC_MODAL_STATE()`` can also be used:
+
+#define ALTMODEX_CONF_A = TYPEC_MODAL_STATE(0);
+#define ALTMODEX_CONF_B = TYPEC_MODAL_STATE(1);
+
+Notification chain
+~~~~~~~~~~~~~~~~~~
+
+The drivers for the components that the alternate modes are designed for need to
+get details regarding the results of the negotiation with the partner, and the
+pin configuration of the connector. In case of DisplayPort alternate mode for
+example, the GPU drivers will need to know those details. In case of
+Thunderbolt alternate mode, the thunderbolt drivers will need to know them, and
+so on.
+
+The notification chain is designed for this purpose. The drivers can register
+notifiers with :c:func:`typec_altmode_register_notifier()`.
+
+Cable plug alternate modes
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The alternate mode drivers are not bind to cable plug alternate mode devices,
+only to the partner alternate mode devices. If the alternate mode supports, or
+requires, a cable that responds to SOP Prime, and optionally SOP Double Prime
+messages, the driver for that alternate mode must request handle to the cable
+plug alternate modes using :c:func:`typec_altmode_get_plug()`, and taking over
+their control.
+
+Driver API
+----------
+
+Alternate mode driver registering/unregistering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_register_driver typec_altmode_unregister_driver
+
+Alternate mode driver operations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_register_ops typec_altmode_enter typec_altmode_exit typec_altmode_attention typec_altmode_vdm typec_altmode_notify
+
+API for the port drivers
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_match_altmode
+
+Cable Plug operations
+~~~~~~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: drivers/usb/typec/bus.c
+   :functions: typec_altmode_get_plug typec_altmode_put_plug
+
+Notifications
+~~~~~~~~~~~~~
+.. kernel-doc:: drivers/usb/typec/class.c
+   :functions: typec_altmode_register_notifier typec_altmode_unregister_notifier
diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
index 1f599a6c30cc..5466c62c8e97 100644
--- a/drivers/usb/typec/Makefile
+++ b/drivers/usb/typec/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_TYPEC)		+= typec.o
-typec-y				:= class.o mux.o
+typec-y				:= class.o mux.o bus.o
 obj-$(CONFIG_TYPEC_TCPM)	+= tcpm.o
 obj-y				+= fusb302/
 obj-$(CONFIG_TYPEC_WCOVE)	+= typec_wcove.o
diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
new file mode 100644
index 000000000000..92944aaf3d6a
--- /dev/null
+++ b/drivers/usb/typec/bus.c
@@ -0,0 +1,421 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * Bus for USB Type-C Alternate Modes
+ *
+ * Copyright (C) 2018 Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ */
+
+#include "bus.h"
+
+/* -------------------------------------------------------------------------- */
+/* Common API */
+
+/**
+ * typec_altmode_notify - Communication between the OS and alternate mode driver
+ * @adev: Handle to the alternate mode
+ * @conf: Alternate mode specific configuration value
+ * @data: Alternate mode specific data
+ *
+ * The primary purpose for this function is to allow the alternate mode drivers
+ * to tell which pin configuration has been negotiated with the partner. That
+ * information will then be used for example to configure the muxes.
+ * Communication to the other direction is also possible, and low level device
+ * drivers can also send notifications to the alternate mode drivers. The actual
+ * communication will be specific for every SVID.
+ */
+int typec_altmode_notify(struct typec_altmode *adev,
+			 unsigned long conf, void *data)
+{
+	struct altmode *altmode;
+	struct altmode *partner;
+	int ret;
+
+	/*
+	 * All SVID specific configuration values must start from
+	 * TYPEC_STATE_MODAL. The first values are reserved for the pin states
+	 * defined in USB Type-C specification: TYPEC_STATE_USB and
+	 * TYPEC_STATE_SAFE. We'll follow this rule even with modes that do not
+	 * require pin reconfiguration for the sake of simplicity.
+	 */
+	if (conf < TYPEC_STATE_MODAL)
+		return -EINVAL;
+
+	if (!adev)
+		return 0;
+
+	altmode = to_altmode(adev);
+
+	if (!altmode->partner)
+		return -ENODEV;
+
+	ret = typec_set_mode(typec_altmode2port(adev), (int)conf);
+	if (ret)
+		return ret;
+
+	partner = altmode->partner;
+
+	blocking_notifier_call_chain(is_typec_port(adev->dev.parent) ?
+				     &altmode->nh : &partner->nh,
+				     conf, data);
+
+	if (partner->ops && partner->ops->notify)
+		return partner->ops->notify(&partner->adev, conf, data);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_notify);
+
+/**
+ * typec_altmode_enter - Enter Mode
+ * @adev: The alternate mode
+ *
+ * The alternate mode drivers use this function to enter mode. The port drivers
+ * use this to inform the alternate mode drivers that their mode has been
+ * entered successfully.
+ */
+int typec_altmode_enter(struct typec_altmode *adev)
+{
+	struct altmode *partner = to_altmode(adev)->partner;
+	struct typec_altmode *pdev = &partner->adev;
+	int ret;
+
+	if (is_typec_port(adev->dev.parent)) {
+		typec_altmode_update_active(pdev, pdev->mode, true);
+		sysfs_notify(&pdev->dev.kobj, NULL, "active");
+		goto enter_mode;
+	}
+
+	if (!pdev->active)
+		return -EPERM;
+
+	/* First moving to USB Safe State */
+	ret = typec_set_mode(typec_altmode2port(adev), TYPEC_STATE_SAFE);
+	if (ret)
+		return ret;
+
+	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
+
+enter_mode:
+	/* Enter Mode command */
+	if (partner->ops && partner->ops->enter)
+		partner->ops->enter(pdev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_enter);
+
+/**
+ * typec_altmode_enter - Exit Mode
+ * @adev: The alternate mode
+ *
+ * The alternate mode drivers use this function to exit mode. The port drivers
+ * can also inform the alternate mode drivers with this function that the mode
+ * was successfully exited.
+ */
+int typec_altmode_exit(struct typec_altmode *adev)
+{
+	struct altmode *partner = to_altmode(adev)->partner;
+	struct typec_port *port = typec_altmode2port(adev);
+	struct typec_altmode *pdev = &partner->adev;
+	int ret;
+
+	/* In case of port, just calling the driver and exiting */
+	if (is_typec_port(adev->dev.parent)) {
+		typec_altmode_update_active(pdev, pdev->mode, false);
+		sysfs_notify(&pdev->dev.kobj, NULL, "active");
+
+		if (partner->ops && partner->ops->exit)
+			partner->ops->exit(pdev);
+		return 0;
+	}
+
+	/* Moving to USB Safe State */
+	ret = typec_set_mode(port, TYPEC_STATE_SAFE);
+	if (ret)
+		return ret;
+
+	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
+
+	/* Exit Mode command */
+	if (partner->ops && partner->ops->exit)
+		partner->ops->exit(pdev);
+
+	/* Back to USB operation */
+	ret = typec_set_mode(port, TYPEC_STATE_USB);
+	if (ret)
+		return ret;
+
+	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_USB, NULL);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_exit);
+
+/**
+ * typec_altmode_attention - Attention command
+ * @adev: The alternate mode
+ * @vdo: VDO for the Attention command
+ *
+ * Notifies the partner of @adev about Attention command.
+ */
+void typec_altmode_attention(struct typec_altmode *adev, const u32 vdo)
+{
+	struct altmode *partner = to_altmode(adev)->partner;
+
+	if (partner && partner->ops && partner->ops->attention)
+		partner->ops->attention(&partner->adev, vdo);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_attention);
+
+/**
+ * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
+ * @adev: Alternate mode handle
+ * @header: VDM Header
+ * @vdo: Array of Vendor Defined Data Objects
+ * @count: Number of Data Objects
+ *
+ * The alternate mode drivers use this function for SVID specific communication
+ * with the partner. The port drivers use it to deliver the Structured VDMs
+ * received from the partners to the alternate mode drivers.
+ */
+int typec_altmode_vdm(struct typec_altmode *adev,
+		      const u32 header, const u32 *vdo, int count)
+{
+	struct altmode *altmode;
+	struct altmode *partner;
+
+	if (!adev)
+		return 0;
+
+	altmode = to_altmode(adev);
+
+	if (!altmode->partner)
+		return -ENODEV;
+
+	partner = altmode->partner;
+
+	if (partner->ops && partner->ops->vdm)
+		return partner->ops->vdm(&partner->adev, header, vdo, count);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_vdm);
+
+void typec_altmode_register_ops(struct typec_altmode *adev,
+				const struct typec_altmode_ops *ops)
+{
+	to_altmode(adev)->ops = ops;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_register_ops);
+
+/* -------------------------------------------------------------------------- */
+/* API for the alternate mode drivers */
+
+/**
+ * typec_altmode_get_plug - Find cable plug alternate mode
+ * @adev: Handle to partner alternate mode
+ * @index: Cable plug index
+ *
+ * Increment reference count for cable plug alternate mode device. Returns
+ * handle to the cable plug alternate mode, or NULL if none is found.
+ */
+struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
+					     int index)
+{
+	struct altmode *port = to_altmode(adev)->partner;
+
+	if (port->plug[index]) {
+		get_device(&port->plug[index]->adev.dev);
+		return &port->plug[index]->adev;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
+
+/**
+ * typec_altmode_get_plug - Decrement cable plug alternate mode reference count
+ * @plug: Handle to the cable plug alternate mode
+ */
+void typec_altmode_put_plug(struct typec_altmode *plug)
+{
+	if (plug)
+		put_device(&plug->dev);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_put_plug);
+
+int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
+				    struct module *module)
+{
+	if (!drv->probe)
+		return -EINVAL;
+
+	drv->driver.owner = module;
+	drv->driver.bus = &typec_bus;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(__typec_altmode_register_driver);
+
+void typec_altmode_unregister_driver(struct typec_altmode_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_unregister_driver);
+
+/* -------------------------------------------------------------------------- */
+/* API for the port drivers */
+
+bool typec_altmode_ufp_capable(struct typec_altmode *adev)
+{
+	struct altmode *altmode = to_altmode(adev);
+
+	if (!is_typec_port(adev->dev.parent))
+		return false;
+
+	return !(altmode->roles == TYPEC_PORT_DFP);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_ufp_capable);
+
+bool typec_altmode_dfp_capable(struct typec_altmode *adev)
+{
+	struct altmode *altmode = to_altmode(adev);
+
+	if (!is_typec_port(adev->dev.parent))
+		return false;
+
+	return !(altmode->roles == TYPEC_PORT_UFP);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_dfp_capable);
+
+/**
+ * typec_match_altmode - Match SVID to an array of alternate modes
+ * @altmodes: Array of alternate modes
+ * @n: Number of elements in the array, or -1 for NULL termiated arrays
+ * @svid: Standard or Vendor ID to match with
+ *
+ * Return pointer to an alternate mode with SVID mathing @svid, or NULL when no
+ * match is found.
+ */
+struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
+					  size_t n, u16 svid, u8 mode)
+{
+	int i;
+
+	for (i = 0; i < n; i++) {
+		if (!altmodes[i])
+			break;
+		if (altmodes[i]->svid == svid && altmodes[i]->mode == mode)
+			return altmodes[i];
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(typec_match_altmode);
+
+/* -------------------------------------------------------------------------- */
+
+static ssize_t
+description_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct typec_altmode *alt = to_typec_altmode(dev);
+
+	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
+}
+static DEVICE_ATTR_RO(description);
+
+static struct attribute *typec_attrs[] = {
+	&dev_attr_description.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(typec);
+
+static int typec_match(struct device *dev, struct device_driver *driver)
+{
+	struct typec_altmode_driver *drv = to_altmode_driver(driver);
+	struct typec_altmode *altmode = to_typec_altmode(dev);
+	const struct typec_device_id *id;
+
+	for (id = drv->id_table; id->svid; id++)
+		if ((id->svid == altmode->svid) &&
+		    (id->mode == TYPEC_ANY_MODE || id->mode == altmode->mode))
+			return 1;
+	return 0;
+}
+
+static int typec_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct typec_altmode *altmode = to_typec_altmode(dev);
+
+	if (add_uevent_var(env, "SVID=%04X", altmode->svid))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "MODE=%u", altmode->mode))
+		return -ENOMEM;
+
+	return add_uevent_var(env, "MODALIAS=typec:id%04Xm%02X",
+			      altmode->svid, altmode->mode);
+}
+
+static int typec_altmode_create_links(struct altmode *alt)
+{
+	struct device *port_dev = &alt->partner->adev.dev;
+	struct device *dev = &alt->adev.dev;
+	int err;
+
+	err = sysfs_create_link(&dev->kobj, &port_dev->kobj, "port");
+	if (err)
+		return err;
+
+	err = sysfs_create_link(&port_dev->kobj, &dev->kobj, "partner");
+	if (err)
+		sysfs_remove_link(&dev->kobj, "port");
+
+	return err;
+}
+
+static int typec_probe(struct device *dev)
+{
+	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct altmode *altmode = to_altmode(adev);
+
+	/* Fail if the port does not support the alternate mode */
+	if (!altmode->partner)
+		return -ENODEV;
+
+	if (typec_altmode_create_links(altmode))
+		dev_warn(dev, "failed to create symlinks\n");
+
+	return drv->probe(adev, altmode->partner->adev.vdo);
+}
+
+static int typec_remove(struct device *dev)
+{
+	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct altmode *altmode = to_altmode(adev);
+
+	if (!is_typec_port(adev->dev.parent)) {
+		sysfs_remove_link(&altmode->partner->adev.dev.kobj, "partner");
+		sysfs_remove_link(&adev->dev.kobj, "port");
+	}
+
+	if (drv->remove)
+		drv->remove(to_typec_altmode(dev));
+
+	if (adev->active)
+		typec_altmode_exit(adev);
+
+	return 0;
+}
+
+struct bus_type typec_bus = {
+	.name = "typec",
+	.dev_groups = typec_groups,
+	.match = typec_match,
+	.uevent = typec_uevent,
+	.probe = typec_probe,
+	.remove = typec_remove,
+};
diff --git a/drivers/usb/typec/bus.h b/drivers/usb/typec/bus.h
new file mode 100644
index 000000000000..38585363952f
--- /dev/null
+++ b/drivers/usb/typec/bus.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __USB_TYPEC_ALTMODE_H__
+#define __USB_TYPEC_ALTMODE_H__
+
+#include <linux/usb/typec.h>
+
+struct bus_type;
+
+struct altmode {
+	unsigned int			id;
+	struct typec_altmode		adev;
+
+	enum typec_port_data		roles;
+
+	struct attribute		*attrs[5];
+	char				group_name[6];
+	struct attribute_group		group;
+	const struct attribute_group	*groups[2];
+
+	struct altmode			*partner;
+	struct altmode			*plug[2];
+	const struct typec_altmode_ops	*ops;
+
+	struct blocking_notifier_head	nh;
+};
+
+#define to_altmode(d) container_of(d, struct altmode, adev)
+
+extern struct bus_type typec_bus;
+extern const struct device_type typec_altmode_dev_type;
+extern const struct device_type typec_port_dev_type;
+
+#define is_typec_altmode(_dev_) (_dev_->type == &typec_altmode_dev_type)
+#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
+
+#endif /* __USB_TYPEC_ALTMODE_H__ */
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 26eeab1491b7..33fffb853994 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -6,6 +6,7 @@
  * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
  */
 
+#include <linux/connection.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -13,25 +14,12 @@
 #include <linux/usb/typec.h>
 #include <linux/usb/typec_mux.h>
 
-struct typec_altmode {
-	struct device			dev;
-	u16				svid;
-	u8				mode;
-
-	u32				vdo;
-	char				*desc;
-	enum typec_port_type		roles;
-	unsigned int			active:1;
-
-	struct attribute		*attrs[5];
-	char				group_name[6];
-	struct attribute_group		group;
-	const struct attribute_group	*groups[2];
-};
+#include "bus.h"
 
 struct typec_plug {
 	struct device			dev;
 	enum typec_plug_index		index;
+	struct ida			mode_ids;
 };
 
 struct typec_cable {
@@ -46,11 +34,13 @@ struct typec_partner {
 	unsigned int			usb_pd:1;
 	struct usb_pd_identity		*identity;
 	enum typec_accessory		accessory;
+	struct ida			mode_ids;
 };
 
 struct typec_port {
 	unsigned int			id;
 	struct device			dev;
+	struct ida			mode_ids;
 
 	int				prefer_role;
 	enum typec_data_role		data_role;
@@ -71,17 +61,14 @@ struct typec_port {
 #define to_typec_plug(_dev_) container_of(_dev_, struct typec_plug, dev)
 #define to_typec_cable(_dev_) container_of(_dev_, struct typec_cable, dev)
 #define to_typec_partner(_dev_) container_of(_dev_, struct typec_partner, dev)
-#define to_altmode(_dev_) container_of(_dev_, struct typec_altmode, dev)
 
 static const struct device_type typec_partner_dev_type;
 static const struct device_type typec_cable_dev_type;
 static const struct device_type typec_plug_dev_type;
-static const struct device_type typec_port_dev_type;
 
 #define is_typec_partner(_dev_) (_dev_->type == &typec_partner_dev_type)
 #define is_typec_cable(_dev_) (_dev_->type == &typec_cable_dev_type)
 #define is_typec_plug(_dev_) (_dev_->type == &typec_plug_dev_type)
-#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
 
 static DEFINE_IDA(typec_index_ida);
 static struct class *typec_class;
@@ -163,27 +150,141 @@ static void typec_report_identity(struct device *dev)
 /* ------------------------------------------------------------------------- */
 /* Alternate Modes */
 
+static int altmode_match(struct device *dev, void *data)
+{
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct typec_device_id *id = data;
+
+	if (!is_typec_altmode(dev))
+		return 0;
+
+	return ((adev->svid == id->svid) && (adev->mode == id->mode));
+}
+
+static void typec_altmode_get_partner(struct altmode *altmode)
+{
+	struct typec_altmode *adev = &altmode->adev;
+	struct typec_device_id id = { adev->svid, adev->mode, };
+	struct typec_port *port = typec_altmode2port(adev);
+	struct altmode *partner;
+	struct device *dev;
+
+	dev = device_find_child(&port->dev, &id, altmode_match);
+	if (!dev)
+		return;
+
+	/* Bind the port alt mode to the partner/plug alt mode. */
+	partner = to_altmode(to_typec_altmode(dev));
+	altmode->partner = partner;
+
+	/* Bind the partner/plug alt mode to the port alt mode. */
+	if (is_typec_plug(adev->dev.parent)) {
+		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
+
+		partner->plug[plug->index] = altmode;
+	} else {
+		partner->partner = altmode;
+	}
+}
+
+static void typec_altmode_put_partner(struct altmode *altmode)
+{
+	struct altmode *partner = altmode->partner;
+	struct typec_altmode *adev;
+
+	if (!partner)
+		return;
+
+	adev = &partner->adev;
+
+	if (is_typec_plug(adev->dev.parent)) {
+		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
+
+		partner->plug[plug->index] = NULL;
+	} else {
+		partner->partner = NULL;
+	}
+	put_device(&adev->dev);
+}
+
+static int __typec_port_match(struct device *dev, const void *name)
+{
+	return !strcmp((const char *)name, dev_name(dev));
+}
+
+static void *typec_port_match(struct devcon *con, int ep, void *data)
+{
+	return class_find_device(typec_class, NULL, con->endpoint[ep],
+				 __typec_port_match);
+}
+
+struct typec_altmode *
+typec_altmode_register_notifier(struct device *dev, u16 svid, u8 mode,
+				struct notifier_block *nb)
+{
+	struct typec_device_id id = { svid, mode, };
+	struct device *altmode_dev;
+	struct device *port_dev;
+	struct altmode *altmode;
+	int ret;
+
+	/* Find the port linked to the caller */
+	port_dev = __device_find_connection(dev, NULL, NULL, typec_port_match);
+	if (!port_dev)
+		return ERR_PTR(-ENODEV);
+
+	/* Find the altmode with matching svid */
+	altmode_dev = device_find_child(port_dev, &id, altmode_match);
+
+	put_device(port_dev);
+
+	if (!altmode_dev)
+		return ERR_PTR(-ENODEV);
+
+	altmode = to_altmode(to_typec_altmode(altmode_dev));
+
+	/* Register notifier */
+	ret = blocking_notifier_chain_register(&altmode->nh, nb);
+	if (ret) {
+		put_device(altmode_dev);
+		return ERR_PTR(ret);
+	}
+
+	return &altmode->adev;
+}
+EXPORT_SYMBOL_GPL(typec_altmode_register_notifier);
+
+void typec_altmode_unregister_notifier(struct typec_altmode *adev,
+				       struct notifier_block *nb)
+{
+	struct altmode *altmode = to_altmode(adev);
+
+	blocking_notifier_chain_unregister(&altmode->nh, nb);
+	put_device(&adev->dev);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_unregister_notifier);
+
 /**
  * typec_altmode_update_active - Report Enter/Exit mode
- * @alt: Handle to the alternate mode
+ * @adev: Handle to the alternate mode
  * @mode: Mode index
  * @active: True when the mode has been entered
  *
  * If a partner or cable plug executes Enter/Exit Mode command successfully, the
  * drivers use this routine to report the updated state of the mode.
  */
-void typec_altmode_update_active(struct typec_altmode *alt, int mode,
+void typec_altmode_update_active(struct typec_altmode *adev, int mode,
 				 bool active)
 {
 	char dir[6];
 
-	if (alt->active == active)
+	if (adev->active == active)
 		return;
 
-	alt->active = active;
+	adev->active = active;
 	snprintf(dir, sizeof(dir), "mode%d", mode);
-	sysfs_notify(&alt->dev.kobj, dir, "active");
-	kobject_uevent(&alt->dev.kobj, KOBJ_CHANGE);
+	sysfs_notify(&adev->dev.kobj, dir, "active");
+	kobject_uevent(&adev->dev.kobj, KOBJ_CHANGE);
 }
 EXPORT_SYMBOL_GPL(typec_altmode_update_active);
 
@@ -210,7 +311,7 @@ EXPORT_SYMBOL_GPL(typec_altmode2port);
 static ssize_t
 vdo_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *alt = to_typec_altmode(dev);
 
 	return sprintf(buf, "0x%08x\n", alt->vdo);
 }
@@ -219,7 +320,7 @@ static DEVICE_ATTR_RO(vdo);
 static ssize_t
 description_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *alt = to_typec_altmode(dev);
 
 	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
 }
@@ -228,28 +329,46 @@ static DEVICE_ATTR_RO(description);
 static ssize_t
 active_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *alt = to_typec_altmode(dev);
 
 	return sprintf(buf, "%s\n", alt->active ? "yes" : "no");
 }
 
-static ssize_t
-active_store(struct device *dev, struct device_attribute *attr,
-			   const char *buf, size_t size)
+static ssize_t active_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t size)
 {
-	struct typec_altmode *alt = to_altmode(dev);
-	struct typec_port *port = typec_altmode2port(alt);
-	bool activate;
+	struct typec_altmode *adev = to_typec_altmode(dev);
+	struct typec_port *port = typec_altmode2port(adev);
+	struct altmode *altmode = to_altmode(adev);
+	bool enter;
 	int ret;
 
 	if (!port->cap->activate_mode)
 		return -EOPNOTSUPP;
 
-	ret = kstrtobool(buf, &activate);
+	ret = kstrtobool(buf, &enter);
 	if (ret)
 		return ret;
 
-	ret = port->cap->activate_mode(port->cap, alt->mode, activate);
+	if (adev->active == enter)
+		return size;
+
+	if (is_typec_port(adev->dev.parent)) {
+		typec_altmode_update_active(adev, adev->mode, enter);
+		sysfs_notify(&adev->dev.kobj, NULL, "active");
+
+		if (!altmode->partner)
+			return size;
+	} else {
+		adev = &altmode->partner->adev;
+
+		if (!adev->active) {
+			dev_warn(dev, "port has the mode disabled\n");
+			return -EPERM;
+		}
+	}
+
+	ret = port->cap->activate_mode(adev, enter);
 	if (ret)
 		return ret;
 
@@ -261,7 +380,7 @@ static ssize_t
 supported_roles_show(struct device *dev, struct device_attribute *attr,
 		     char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct altmode *alt = to_altmode(to_typec_altmode(dev));
 	ssize_t ret;
 
 	switch (alt->roles) {
@@ -280,29 +399,72 @@ supported_roles_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(supported_roles);
 
-static void typec_altmode_release(struct device *dev)
+static ssize_t
+mode_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *adev = to_typec_altmode(dev);
 
-	kfree(alt);
+	return sprintf(buf, "%u\n", adev->mode);
 }
+static DEVICE_ATTR_RO(mode);
 
-static ssize_t svid_show(struct device *dev, struct device_attribute *attr,
-			 char *buf)
+static ssize_t
+svid_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct typec_altmode *alt = to_altmode(dev);
+	struct typec_altmode *adev = to_typec_altmode(dev);
 
-	return sprintf(buf, "%04x\n", alt->svid);
+	return sprintf(buf, "%04x\n", adev->svid);
 }
 static DEVICE_ATTR_RO(svid);
 
 static struct attribute *typec_altmode_attrs[] = {
+	&dev_attr_active.attr,
+	&dev_attr_mode.attr,
 	&dev_attr_svid.attr,
+	&dev_attr_vdo.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(typec_altmode);
 
-static const struct device_type typec_altmode_dev_type = {
+static int altmode_id_get(struct device *dev)
+{
+	struct ida *ids;
+
+	if (is_typec_partner(dev))
+		ids = &to_typec_partner(dev)->mode_ids;
+	else if (is_typec_plug(dev))
+		ids = &to_typec_plug(dev)->mode_ids;
+	else
+		ids = &to_typec_port(dev)->mode_ids;
+
+	return ida_simple_get(ids, 0, 0, GFP_KERNEL);
+}
+
+static void altmode_id_remove(struct device *dev, int id)
+{
+	struct ida *ids;
+
+	if (is_typec_partner(dev))
+		ids = &to_typec_partner(dev)->mode_ids;
+	else if (is_typec_plug(dev))
+		ids = &to_typec_plug(dev)->mode_ids;
+	else
+		ids = &to_typec_port(dev)->mode_ids;
+
+	ida_simple_remove(ids, id);
+}
+
+static void typec_altmode_release(struct device *dev)
+{
+	struct altmode *alt = to_altmode(to_typec_altmode(dev));
+
+	typec_altmode_put_partner(alt);
+
+	altmode_id_remove(alt->adev.dev.parent, alt->id);
+	kfree(alt);
+}
+
+const struct device_type typec_altmode_dev_type = {
 	.name = "typec_alternate_mode",
 	.groups = typec_altmode_groups,
 	.release = typec_altmode_release,
@@ -312,58 +474,72 @@ static struct typec_altmode *
 typec_register_altmode(struct device *parent,
 		       const struct typec_altmode_desc *desc)
 {
-	struct typec_altmode *alt;
+	unsigned int id = altmode_id_get(parent);
+	bool is_port = is_typec_port(parent);
+	struct altmode *alt;
 	int ret;
 
 	alt = kzalloc(sizeof(*alt), GFP_KERNEL);
 	if (!alt)
 		return ERR_PTR(-ENOMEM);
 
-	alt->svid = desc->svid;
-	alt->mode = desc->mode;
-	alt->vdo = desc->vdo;
+	alt->adev.svid = desc->svid;
+	alt->adev.mode = desc->mode;
+	alt->adev.vdo = desc->vdo;
 	alt->roles = desc->roles;
+	alt->id = id;
 
 	alt->attrs[0] = &dev_attr_vdo.attr;
 	alt->attrs[1] = &dev_attr_description.attr;
 	alt->attrs[2] = &dev_attr_active.attr;
 
-	if (is_typec_port(parent))
+	if (is_port) {
 		alt->attrs[3] = &dev_attr_supported_roles.attr;
+		alt->adev.active = true; /* Enabled by default */
+	}
 
 	sprintf(alt->group_name, "mode%d", desc->mode);
 	alt->group.name = alt->group_name;
 	alt->group.attrs = alt->attrs;
 	alt->groups[0] = &alt->group;
 
-	alt->dev.parent = parent;
-	alt->dev.groups = alt->groups;
-	alt->dev.type = &typec_altmode_dev_type;
-	dev_set_name(&alt->dev, "%s-%04x:%u", dev_name(parent),
-		     alt->svid, alt->mode);
+	alt->adev.dev.parent = parent;
+	alt->adev.dev.groups = alt->groups;
+	alt->adev.dev.type = &typec_altmode_dev_type;
+	dev_set_name(&alt->adev.dev, "%s.%u", dev_name(parent), id);
+
+	/* Link partners and plugs with the ports */
+	if (is_port)
+		BLOCKING_INIT_NOTIFIER_HEAD(&alt->nh);
+	else
+		typec_altmode_get_partner(alt);
 
-	ret = device_register(&alt->dev);
+	/* The partners are bind to drivers */
+	if (is_typec_partner(parent))
+		alt->adev.dev.bus = &typec_bus;
+
+	ret = device_register(&alt->adev.dev);
 	if (ret) {
 		dev_err(parent, "failed to register alternate mode (%d)\n",
 			ret);
-		put_device(&alt->dev);
+		put_device(&alt->adev.dev);
 		return ERR_PTR(ret);
 	}
 
-	return alt;
+	return &alt->adev;
 }
 
 /**
  * typec_unregister_altmode - Unregister Alternate Mode
- * @alt: The alternate mode to be unregistered
+ * @adev: The alternate mode to be unregistered
  *
  * Unregister device created with typec_partner_register_altmode(),
  * typec_plug_register_altmode() or typec_port_register_altmode().
  */
-void typec_unregister_altmode(struct typec_altmode *alt)
+void typec_unregister_altmode(struct typec_altmode *adev)
 {
-	if (!IS_ERR_OR_NULL(alt))
-		device_unregister(&alt->dev);
+	if (!IS_ERR_OR_NULL(adev))
+		device_unregister(&adev->dev);
 }
 EXPORT_SYMBOL_GPL(typec_unregister_altmode);
 
@@ -401,6 +577,7 @@ static void typec_partner_release(struct device *dev)
 {
 	struct typec_partner *partner = to_typec_partner(dev);
 
+	ida_destroy(&partner->mode_ids);
 	kfree(partner);
 }
 
@@ -466,6 +643,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
 	if (!partner)
 		return ERR_PTR(-ENOMEM);
 
+	ida_init(&partner->mode_ids);
 	partner->usb_pd = desc->usb_pd;
 	partner->accessory = desc->accessory;
 
@@ -514,6 +692,7 @@ static void typec_plug_release(struct device *dev)
 {
 	struct typec_plug *plug = to_typec_plug(dev);
 
+	ida_destroy(&plug->mode_ids);
 	kfree(plug);
 }
 
@@ -566,6 +745,7 @@ struct typec_plug *typec_register_plug(struct typec_cable *cable,
 
 	sprintf(name, "plug%d", desc->index);
 
+	ida_init(&plug->mode_ids);
 	plug->index = desc->index;
 	plug->dev.class = typec_class;
 	plug->dev.parent = &cable->dev;
@@ -1080,12 +1260,13 @@ static void typec_release(struct device *dev)
 	struct typec_port *port = to_typec_port(dev);
 
 	ida_simple_remove(&typec_index_ida, port->id);
+	ida_destroy(&port->mode_ids);
 	typec_switch_put(port->sw);
 	typec_mux_put(port->mux);
 	kfree(port);
 }
 
-static const struct device_type typec_port_dev_type = {
+const struct device_type typec_port_dev_type = {
 	.name = "typec_port",
 	.groups = typec_groups,
 	.uevent = typec_uevent,
@@ -1238,6 +1419,8 @@ EXPORT_SYMBOL_GPL(typec_set_mode);
  * typec_port_register_altmode - Register USB Type-C Port Alternate Mode
  * @port: USB Type-C Port that supports the alternate mode
  * @desc: Description of the alternate mode
+ * @ops: Port specific operations for the alternate mode
+ * @drvdata: Private pointer to driver specific info
  *
  * This routine is used to register an alternate mode that @port is capable of
  * supporting.
@@ -1322,10 +1505,12 @@ struct typec_port *typec_register_port(struct device *parent,
 		break;
 	}
 
+	ida_init(&port->mode_ids);
+	mutex_init(&port->port_type_lock);
+
 	port->id = id;
 	port->cap = cap;
 	port->port_type = cap->type;
-	mutex_init(&port->port_type_lock);
 	port->prefer_role = cap->prefer_role;
 
 	port->dev.class = typec_class;
@@ -1369,8 +1554,19 @@ EXPORT_SYMBOL_GPL(typec_unregister_port);
 
 static int __init typec_init(void)
 {
+	int ret;
+
+	ret = bus_register(&typec_bus);
+	if (ret)
+		return ret;
+
 	typec_class = class_create(THIS_MODULE, "typec");
-	return PTR_ERR_OR_ZERO(typec_class);
+	if (IS_ERR(typec_class)) {
+		bus_unregister(&typec_bus);
+		return PTR_ERR(typec_class);
+	}
+
+	return 0;
 }
 subsys_initcall(typec_init);
 
@@ -1378,6 +1574,7 @@ static void __exit typec_exit(void)
 {
 	class_destroy(typec_class);
 	ida_destroy(&typec_index_ida);
+	bus_unregister(&typec_bus);
 }
 module_exit(typec_exit);
 
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 48fb2b43c35a..17c1a912f524 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -733,4 +733,19 @@ struct tb_service_id {
 #define TBSVC_MATCH_PROTOCOL_VERSION	0x0004
 #define TBSVC_MATCH_PROTOCOL_REVISION	0x0008
 
+/* USB Type-C Alternate Modes */
+
+#define TYPEC_ANY_MODE	0x7
+
+/**
+ * struct typec_device_id - USB Type-C alternate mode identifiers
+ * @svid: Standard or Vendor ID
+ * @mode: Mode index
+ */
+struct typec_device_id {
+	__u16 svid;
+	__u8 mode;
+	kernel_ulong_t driver_data;
+};
+
 #endif /* LINUX_MOD_DEVICETABLE_H */
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index 278b6b42c7ea..a19aa3db4272 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -4,16 +4,13 @@
 #define __LINUX_USB_TYPEC_H
 
 #include <linux/types.h>
-
-/* XXX: Once we have a header for USB Power Delivery, this belongs there */
-#define ALTMODE_MAX_MODES	6
+#include <linux/usb/typec_altmode.h>
 
 /* USB Type-C Specification releases */
 #define USB_TYPEC_REV_1_0	0x100 /* 1.0 */
 #define USB_TYPEC_REV_1_1	0x110 /* 1.1 */
 #define USB_TYPEC_REV_1_2	0x120 /* 1.2 */
 
-struct typec_altmode;
 struct typec_partner;
 struct typec_cable;
 struct typec_plug;
@@ -107,7 +104,7 @@ struct typec_altmode_desc {
 	u8			mode;
 	u32			vdo;
 	/* Only used with ports */
-	enum typec_port_type	roles;
+	enum typec_port_data	roles;
 };
 
 struct typec_altmode
@@ -118,7 +115,8 @@ struct typec_altmode
 			     const struct typec_altmode_desc *desc);
 struct typec_altmode
 *typec_port_register_altmode(struct typec_port *port,
-			     const struct typec_altmode_desc *desc);
+			    const struct typec_altmode_desc *desc);
+
 void typec_unregister_altmode(struct typec_altmode *altmode);
 
 struct typec_port *typec_altmode2port(struct typec_altmode *alt);
@@ -213,12 +211,10 @@ struct typec_capability {
 				  enum typec_role);
 	int		(*vconn_set)(const struct typec_capability *,
 				     enum typec_role);
-
-	int		(*activate_mode)(const struct typec_capability *,
-					 int mode, int activate);
 	int		(*port_type_set)(const struct typec_capability *,
-					enum typec_port_type);
+					 enum typec_port_type);
 
+	int		(*activate_mode)(struct typec_altmode *alt, int active);
 };
 
 /* Specific to try_role(). Indicates the user want's to clear the preference. */
diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
new file mode 100644
index 000000000000..bc765352a3c8
--- /dev/null
+++ b/include/linux/usb/typec_altmode.h
@@ -0,0 +1,136 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __USB_TYPEC_ALTMODE_H
+#define __USB_TYPEC_ALTMODE_H
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+
+#define MODE_DISCOVERY_MAX	6
+
+/**
+ * struct typec_altmode - USB Type-C alternate mode device
+ * @dev: Driver model's view of this device
+ * @svid: Standard or Vendor ID (SVID) of the alternate mode
+ * @mode: Index of the Mode
+ * @vdo: VDO returned by Discover Modes USB PD command
+ * @desc: Optional human readable description of the mode
+ * @active: Tells has the mode been entered or not
+ */
+struct typec_altmode {
+	struct device		dev;
+	u16			svid;
+	int			mode;
+	u32			vdo;
+	char			*desc;
+	bool			active;
+} __packed;
+
+#define to_typec_altmode(d) container_of(d, struct typec_altmode, dev)
+
+static inline void typec_altmode_set_drvdata(struct typec_altmode *altmode,
+					     void *data)
+{
+	dev_set_drvdata(&altmode->dev, data);
+}
+
+static inline void *typec_altmode_get_drvdata(struct typec_altmode *altmode)
+{
+	return dev_get_drvdata(&altmode->dev);
+}
+
+/**
+ * struct typec_altmode_ops - Alternate mode specific operations vector
+ * @enter: Operations to be executed with Enter Mode Command
+ * @exit: Operations to be executed with Exit Mode Command
+ * @attention: Callback for Attention Command
+ * @vdm: Callback for SVID specific commands
+ * @notify: Communication channel for platform and the alternate mode
+ */
+struct typec_altmode_ops {
+	void (*enter)(struct typec_altmode *altmode);
+	void (*exit)(struct typec_altmode *altmode);
+	void (*attention)(struct typec_altmode *altmode, const u32 vdo);
+	int (*vdm)(struct typec_altmode *altmode, const u32 hdr,
+		   const u32 *vdo, int cnt);
+	int (*notify)(struct typec_altmode *altmode, unsigned long conf,
+		      void *data);
+};
+
+void typec_altmode_register_ops(struct typec_altmode *altmode,
+				const struct typec_altmode_ops *ops);
+
+int typec_altmode_enter(struct typec_altmode *altmode);
+int typec_altmode_exit(struct typec_altmode *altmode);
+void typec_altmode_attention(struct typec_altmode *altmode, const u32 vdo);
+int typec_altmode_vdm(struct typec_altmode *altmode,
+		      const u32 header, const u32 *vdo, int count);
+int typec_altmode_notify(struct typec_altmode *altmode, unsigned long conf,
+			 void *data);
+
+/* Return values for type_altmode_vdm() */
+#define VDM_DONE		0 /* Don't care */
+#define VDM_OK			1 /* Suits me */
+
+/*
+ * These are the pin states (USB, Safe and Alt Mode) and accessory modes (Audio
+ * and Debug) defined in USB Type-C Specification. SVID specific pin states are
+ * expected to follow and start from the value TYPEC_STATE_MODAL.
+ *
+ * Port drivers should use TYPEC_STATE_AUDIO and TYPEC_STATE_DEBUG as the
+ * operation value for typec_set_mode() when accessory modes are in use.
+ *
+ * NOTE: typec_altmode_notify() does not accept values smaller then
+ * TYPEC_STATE_MODAL. USB Type-C bus will follow USB Type-C Specification with
+ * TYPEC_STATE_USB and TYPEC_STATE_SAFE.
+ */
+enum {
+	TYPEC_STATE_USB,	/* USB Operation */
+	TYPEC_STATE_AUDIO,	/* Audio Accessory */
+	TYPEC_STATE_DEBUG,	/* Debug Accessory */
+	TYPEC_STATE_SAFE,	/* USB Safe State */
+	TYPEC_STATE_MODAL,	/* Alternate Modes */
+};
+
+#define TYPEC_MODAL_STATE(_state_)	((_state_) + TYPEC_STATE_MODAL)
+
+struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *altmode,
+					     int index);
+void typec_altmode_put_plug(struct typec_altmode *plug);
+
+bool typec_altmode_ufp_capable(struct typec_altmode *altmode);
+bool typec_altmode_dfp_capable(struct typec_altmode *altmode);
+struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
+					  size_t n, u16 svid, u8 mode);
+
+/**
+ * struct typec_altmode_driver - USB Type-C alternate mode device driver
+ * @id_table: Null terminated array of SVIDs
+ * @probe: Callback for device binding
+ * @remove: Callback for device unbinding
+ * @driver: Device driver model driver
+ *
+ * These drivers will be bind to the partner alternate mode devices. They will
+ * handle all SVID specific communication.
+ */
+struct typec_altmode_driver {
+	const struct typec_device_id *id_table;
+	int (*probe)(struct typec_altmode *altmode, u32 port_vdo);
+	void (*remove)(struct typec_altmode *altmode);
+	struct device_driver driver;
+};
+
+#define to_altmode_driver(d) container_of(d, struct typec_altmode_driver, \
+					  driver)
+
+#define typec_altmode_register_driver(drv) \
+		__typec_altmode_register_driver(drv, THIS_MODULE)
+int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
+				    struct module *module);
+void typec_altmode_unregister_driver(struct typec_altmode_driver *drv);
+
+#define module_typec_altmode_driver(__typec_altmode_driver) \
+	module_driver(__typec_altmode_driver, typec_altmode_register_driver, \
+		      typec_altmode_unregister_driver)
+
+#endif /* __USB_TYPEC_ALTMODE_H */
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index 9fad6afe4c41..c48c7f56ae64 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -218,5 +218,9 @@ int main(void)
 	DEVID_FIELD(tb_service_id, protocol_version);
 	DEVID_FIELD(tb_service_id, protocol_revision);
 
+	DEVID(typec_device_id);
+	DEVID_FIELD(typec_device_id, svid);
+	DEVID_FIELD(typec_device_id, mode);
+
 	return 0;
 }
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index b9beeaa4695b..a8afba836409 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1341,6 +1341,19 @@ static int do_tbsvc_entry(const char *filename, void *symval, char *alias)
 }
 ADD_TO_DEVTABLE("tbsvc", tb_service_id, do_tbsvc_entry);
 
+/* Looks like: typec:idNmN */
+static int do_typec_entry(const char *filename, void *symval, char *alias)
+{
+	DEF_FIELD(symval, typec_device_id, svid);
+	DEF_FIELD(symval, typec_device_id, mode);
+
+	sprintf(alias, "typec:id%04X", svid);
+	ADD(alias, "m", mode != TYPEC_ANY_MODE, mode);
+
+	return 1;
+}
+ADD_TO_DEVTABLE("typec", typec_device_id, do_typec_entry);
+
 /* Does namelen bytes of name exactly match the symbol? */
 static bool sym_is(const char *name, unsigned namelen, const char *symbol)
 {

Re: [RFC PATCH v2 2/3] usb: typec: Bus type for alternate modes

[Guenter Roeck]

On Fri, Mar 09, 2018 at 06:19:17PM +0300, Heikki Krogerus wrote:
> Introducing a simple bus for the alternate modes. Bus allows
> binding drivers to the discovered alternate modes the
> partners support.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  Documentation/ABI/obsolete/sysfs-class-typec |  48 +++
>  Documentation/ABI/testing/sysfs-bus-typec    |  51 ++++
>  Documentation/ABI/testing/sysfs-class-typec  |  62 +---
>  Documentation/driver-api/usb/typec_bus.rst   | 143 +++++++++
>  drivers/usb/typec/Makefile                   |   2 +-
>  drivers/usb/typec/bus.c                      | 421 +++++++++++++++++++++++++++
>  drivers/usb/typec/bus.h                      |  37 +++
>  drivers/usb/typec/class.c                    | 325 +++++++++++++++++----
>  include/linux/mod_devicetable.h              |  15 +
>  include/linux/usb/typec.h                    |  16 +-
>  include/linux/usb/typec_altmode.h            | 136 +++++++++
>  scripts/mod/devicetable-offsets.c            |   4 +
>  scripts/mod/file2alias.c                     |  13 +
>  13 files changed, 1138 insertions(+), 135 deletions(-)
>  create mode 100644 Documentation/ABI/obsolete/sysfs-class-typec
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-typec
>  create mode 100644 Documentation/driver-api/usb/typec_bus.rst
>  create mode 100644 drivers/usb/typec/bus.c
>  create mode 100644 drivers/usb/typec/bus.h
>  create mode 100644 include/linux/usb/typec_altmode.h
> 
> diff --git a/Documentation/ABI/obsolete/sysfs-class-typec b/Documentation/ABI/obsolete/sysfs-class-typec
> new file mode 100644
> index 000000000000..32623514ee87
> --- /dev/null
> +++ b/Documentation/ABI/obsolete/sysfs-class-typec
> @@ -0,0 +1,48 @@
> +These files are deprecated and will be removed. The same files are available
> +under /sys/bus/typec (see Documentation/ABI/testing/sysfs-bus-typec).
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		The SVID (Standard or Vendor ID) assigned by USB-IF for this
> +		alternate mode.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Every supported mode will have its own directory. The name of
> +		a mode will be "mode<index>" (for example mode1), where <index>
> +		is the actual index to the mode VDO returned by Discover Modes
> +		USB power delivery command.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows description of the mode. The description is optional for
> +		the drivers, just like with the Billboard Devices.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows the VDO in hexadecimal returned by Discover Modes command
> +		for this mode.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows if the mode is active or not. The attribute can be used
> +		for entering/exiting the mode with partners and cable plugs, and
> +		with the port alternate modes it can be used for disabling
> +		support for specific alternate modes. Entering/exiting modes is
> +		supported as synchronous operation so write(2) to the attribute
> +		does not return until the enter/exit mode operation has
> +		finished. The attribute is notified when the mode is
> +		entered/exited so poll(2) on the attribute wakes up.
> +		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
> +
> +		Valid values: yes, no
> diff --git a/Documentation/ABI/testing/sysfs-bus-typec b/Documentation/ABI/testing/sysfs-bus-typec
> new file mode 100644
> index 000000000000..ead63f97d9a2
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-typec
> @@ -0,0 +1,51 @@
> +What:		/sys/bus/typec/devices/.../active
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows if the mode is active or not. The attribute can be used
> +		for entering/exiting the mode. Entering/exiting modes is
> +		supported as synchronous operation so write(2) to the attribute
> +		does not return until the enter/exit mode operation has
> +		finished. The attribute is notified when the mode is
> +		entered/exited so poll(2) on the attribute wakes up.
> +		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
> +
> +		Valid values are boolean.
> +
> +What:		/sys/bus/typec/devices/.../description
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows description of the mode. The description is optional for
> +		the drivers, just like with the Billboard Devices.
> +
> +What:		/sys/bus/typec/devices/.../mode
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		The index number of the mode returned by Discover Modes USB
> +		Power Delivery command. Depending on the alternate mode, the
> +		mode index may be significant.
> +
> +		With some alternate modes (SVIDs), the mode index is assigned
> +		for specific functionality in the specification for that
> +		alternate mode.
> +
> +		With other alternate modes, the mode index values are not
> +		assigned, and can not be therefore used for identification. When
> +		the mode index is not assigned, identifying the alternate mode
> +		must be done with either mode VDO or the description.
> +
> +What:		/sys/bus/typec/devices/.../svid
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		The Standard or Vendor ID (SVID) assigned by USB-IF for this
> +		alternate mode.
> +
> +What:		/sys/bus/typec/devices/.../vdo
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows the VDO in hexadecimal returned by Discover Modes command
> +		for this mode.
> diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
> index 5be552e255e9..d7647b258c3c 100644
> --- a/Documentation/ABI/testing/sysfs-class-typec
> +++ b/Documentation/ABI/testing/sysfs-class-typec
> @@ -222,70 +222,12 @@ Description:
>  		available. The value can be polled.
>  
>  
> -Alternate Mode devices.
> +USB Type-C port alternate mode devices.
>  
> -The alternate modes will have Standard or Vendor ID (SVID) assigned by USB-IF.
> -The ports, partners and cable plugs can have alternate modes. A supported SVID
> -will consist of a set of modes. Every SVID a port/partner/plug supports will
> -have a device created for it, and every supported mode for a supported SVID will
> -have its own directory under that device. Below <dev> refers to the device for
> -the alternate mode.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		The SVID (Standard or Vendor ID) assigned by USB-IF for this
> -		alternate mode.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Every supported mode will have its own directory. The name of
> -		a mode will be "mode<index>" (for example mode1), where <index>
> -		is the actual index to the mode VDO returned by Discover Modes
> -		USB power delivery command.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Shows description of the mode. The description is optional for
> -		the drivers, just like with the Billboard Devices.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Shows the VDO in hexadecimal returned by Discover Modes command
> -		for this mode.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Shows if the mode is active or not. The attribute can be used
> -		for entering/exiting the mode with partners and cable plugs, and
> -		with the port alternate modes it can be used for disabling
> -		support for specific alternate modes. Entering/exiting modes is
> -		supported as synchronous operation so write(2) to the attribute
> -		does not return until the enter/exit mode operation has
> -		finished. The attribute is notified when the mode is
> -		entered/exited so poll(2) on the attribute wakes up.
> -		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
> -
> -		Valid values: yes, no
> -
> -What:		/sys/class/typec/<port>/<dev>/mode<index>/supported_roles
> +What:		/sys/class/typec/<port>/<alt mode>/supported_roles
>  Date:		April 2017
>  Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
>  Description:
>  		Space separated list of the supported roles.
>  
> -		This attribute is available for the devices describing the
> -		alternate modes a port supports, and it will not be exposed with
> -		the devices presenting the alternate modes the partners or cable
> -		plugs support.
> -
>  		Valid values: source, sink
> diff --git a/Documentation/driver-api/usb/typec_bus.rst b/Documentation/driver-api/usb/typec_bus.rst
> new file mode 100644
> index 000000000000..ef3c049a8a7f
> --- /dev/null
> +++ b/Documentation/driver-api/usb/typec_bus.rst
> @@ -0,0 +1,143 @@
> +
> +API for USB Type-C Alternate Mode drivers
> +=========================================
> +
> +Introduction
> +------------
> +
> +Alternate modes require communication with the partner using Vendor Defined
> +Messages (VDM) as defined in USB Type-C and USB Power Delivery Specifications.
> +The communication is SVID (Standard or Vendor ID) specific, i.e. specific for
> +every alternate mode, so every alternate mode will need custom driver.
> +
> +USB Type-C bus allows binding a driver to the discovered partner alternate
> +modes by using the SVID and the mode number.
> +
> +USB Type-C Connector Class provides a device for every alternate mode a port
> +supports, and separate device for every alternate mode the partner supports.
> +The drivers for the alternate modes are bind to the partner alternate mode
> +devices, and the port alternate mode devices must be handled by the port
> +drivers.
> +
> +When a new partner alternate mode device is registered, it is linked to the
> +alternate mode device of the port that the partner is attached to, that has
> +matching SVID and mode. Communication between the port driver and alternate mode
> +driver will happen using the same API.
> +
> +The port alternate mode devices are used as a proxy between the partner and the
> +alternate mode drivers, so the port drivers are only expected to pass the SVID
> +specific commands from the alternate mode drivers to the partner, and from the
> +partners to the alternate mode drivers. No direct SVID specific communication is
> +needed from the port drivers, but the port drivers need to provide the operation
> +callbacks for the port alternate mode devices, just like the alternate mode
> +drivers need to provide them for the partner alternate mode devices.
> +
> +Usage:
> +------
> +
> +General
> +~~~~~~~
> +
> +By default, the alternate mode drivers are responsible for entering the mode.
> +It is also possible to leave the decision about entering the mode to the user
> +space (See Documentation/ABI/testing/sysfs-class-typec). Port drivers should not
> +enter any modes on their own.
> +
> +The alternate mode drivers need to register their operation vector in their
> +``->probe`` callback with :c:func:`typec_altmode_register_ops()`. They should
> +be registered before the mode is entered using :c:func:`typec_altmode_enter()`.
> +
> +``->vdm`` is the most important callback in the vector. It will be used to
> +deliver all the SVID specific commands from the partner to the alternate mode
> +driver, and vise versa in case of port drivers. The drivers send the SVID
> +specific commands to each other using :c:func:`typec_altmode_vmd()`.
> +
> +If the communication with the partner using the SVID specific commands results
> +in need to re-configure the pins on the connector, the alternate mode driver
> +needs to notify the bus using :c:func:`typec_altmode_notify()`. The driver
> +passes the negotiated SVID specific pin configuration value to the function as
> +parameter. The bus driver will then configure the mux behind the connector using
> +that value as the state value for the mux, and also call blocking notification
> +chain to notify the external drivers about the state of the connector that need
> +to know it.
> +
> +NOTE: The SVID specific pin configuration values must always start from
> +``TYPEC_STATE_MODAL``. USB Type-C specification defines two default states for
> +the connector: ``TYPEC_STATE_USB`` and ``TYPEC_STATE_SAFE``. USB Type-C
> +Specification also defines two Accessory modes, Audio and Debug:
> +``TYPEC_STATE_AUDIO`` and ``TYPEC_STATE_DEBUG`` These values are reserved by the
> +bus as the four first possible values for the state, and attempts to use them
> +from the alternate mode drivers will result in failure. When the alternate mode
> +is entered, the bus will put the connector into ``TYPEC_STATE_SAFE`` before
> +sending Enter or Exit Mode command as defined in USB Type-C Specification, and
> +also put the connector back to ``TYPEC_STATE_USB`` after the mode has been
> +exited.
> +
> +An example of working definitions for SVID specific pin configurations would
> +look like this:
> +
> +enum {
> +	ALTMODEX_CONF_A = TYPEC_STATE_MODAL,
> +	ALTMODEX_CONF_B,
> +	...
> +};
> +
> +Helper macro ``TYPEC_MODAL_STATE()`` can also be used:
> +
> +#define ALTMODEX_CONF_A = TYPEC_MODAL_STATE(0);
> +#define ALTMODEX_CONF_B = TYPEC_MODAL_STATE(1);
> +
> +Notification chain
> +~~~~~~~~~~~~~~~~~~
> +
> +The drivers for the components that the alternate modes are designed for need to
> +get details regarding the results of the negotiation with the partner, and the
> +pin configuration of the connector. In case of DisplayPort alternate mode for
> +example, the GPU drivers will need to know those details. In case of
> +Thunderbolt alternate mode, the thunderbolt drivers will need to know them, and
> +so on.
> +
> +The notification chain is designed for this purpose. The drivers can register
> +notifiers with :c:func:`typec_altmode_register_notifier()`.
> +
> +Cable plug alternate modes
> +~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +The alternate mode drivers are not bind to cable plug alternate mode devices,
> +only to the partner alternate mode devices. If the alternate mode supports, or
> +requires, a cable that responds to SOP Prime, and optionally SOP Double Prime
> +messages, the driver for that alternate mode must request handle to the cable
> +plug alternate modes using :c:func:`typec_altmode_get_plug()`, and taking over
> +their control.
> +
> +Driver API
> +----------
> +
> +Alternate mode driver registering/unregistering
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_altmode_register_driver typec_altmode_unregister_driver
> +
> +Alternate mode driver operations
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_altmode_register_ops typec_altmode_enter typec_altmode_exit typec_altmode_attention typec_altmode_vdm typec_altmode_notify
> +
> +API for the port drivers
> +~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_match_altmode
> +
> +Cable Plug operations
> +~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_altmode_get_plug typec_altmode_put_plug
> +
> +Notifications
> +~~~~~~~~~~~~~
> +.. kernel-doc:: drivers/usb/typec/class.c
> +   :functions: typec_altmode_register_notifier typec_altmode_unregister_notifier
> diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
> index 1f599a6c30cc..5466c62c8e97 100644
> --- a/drivers/usb/typec/Makefile
> +++ b/drivers/usb/typec/Makefile
> @@ -1,6 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_TYPEC)		+= typec.o
> -typec-y				:= class.o mux.o
> +typec-y				:= class.o mux.o bus.o
>  obj-$(CONFIG_TYPEC_TCPM)	+= tcpm.o
>  obj-y				+= fusb302/
>  obj-$(CONFIG_TYPEC_WCOVE)	+= typec_wcove.o
> diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
> new file mode 100644
> index 000000000000..92944aaf3d6a
> --- /dev/null
> +++ b/drivers/usb/typec/bus.c
> @@ -0,0 +1,421 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * Bus for USB Type-C Alternate Modes
> + *
> + * Copyright (C) 2018 Intel Corporation
> + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> + */
> +
> +#include "bus.h"
> +
> +/* -------------------------------------------------------------------------- */
> +/* Common API */
> +
> +/**
> + * typec_altmode_notify - Communication between the OS and alternate mode driver
> + * @adev: Handle to the alternate mode
> + * @conf: Alternate mode specific configuration value
> + * @data: Alternate mode specific data
> + *
> + * The primary purpose for this function is to allow the alternate mode drivers
> + * to tell which pin configuration has been negotiated with the partner. That
> + * information will then be used for example to configure the muxes.
> + * Communication to the other direction is also possible, and low level device
> + * drivers can also send notifications to the alternate mode drivers. The actual
> + * communication will be specific for every SVID.
> + */
> +int typec_altmode_notify(struct typec_altmode *adev,
> +			 unsigned long conf, void *data)
> +{
> +	struct altmode *altmode;
> +	struct altmode *partner;
> +	int ret;
> +
> +	/*
> +	 * All SVID specific configuration values must start from
> +	 * TYPEC_STATE_MODAL. The first values are reserved for the pin states
> +	 * defined in USB Type-C specification: TYPEC_STATE_USB and
> +	 * TYPEC_STATE_SAFE. We'll follow this rule even with modes that do not
> +	 * require pin reconfiguration for the sake of simplicity.
> +	 */
> +	if (conf < TYPEC_STATE_MODAL)
> +		return -EINVAL;
> +
> +	if (!adev)
> +		return 0;
> +
> +	altmode = to_altmode(adev);
> +
> +	if (!altmode->partner)
> +		return -ENODEV;
> +
> +	ret = typec_set_mode(typec_altmode2port(adev), (int)conf);
> +	if (ret)
> +		return ret;
> +
> +	partner = altmode->partner;
> +
> +	blocking_notifier_call_chain(is_typec_port(adev->dev.parent) ?
> +				     &altmode->nh : &partner->nh,
> +				     conf, data);
> +
> +	if (partner->ops && partner->ops->notify)
> +		return partner->ops->notify(&partner->adev, conf, data);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_notify);
> +
> +/**
> + * typec_altmode_enter - Enter Mode
> + * @adev: The alternate mode
> + *
> + * The alternate mode drivers use this function to enter mode. The port drivers
> + * use this to inform the alternate mode drivers that their mode has been
> + * entered successfully.
> + */
> +int typec_altmode_enter(struct typec_altmode *adev)
> +{
> +	struct altmode *partner = to_altmode(adev)->partner;
> +	struct typec_altmode *pdev = &partner->adev;
> +	int ret;
> +
> +	if (is_typec_port(adev->dev.parent)) {
> +		typec_altmode_update_active(pdev, pdev->mode, true);
> +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> +		goto enter_mode;
> +	}
> +
> +	if (!pdev->active)
> +		return -EPERM;
> +
> +	/* First moving to USB Safe State */
> +	ret = typec_set_mode(typec_altmode2port(adev), TYPEC_STATE_SAFE);
> +	if (ret)
> +		return ret;
> +
> +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> +
> +enter_mode:
> +	/* Enter Mode command */
> +	if (partner->ops && partner->ops->enter)
> +		partner->ops->enter(pdev);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_enter);
> +
> +/**
> + * typec_altmode_enter - Exit Mode

typec_altmode_exit

> + * @adev: The alternate mode
> + *
> + * The alternate mode drivers use this function to exit mode. The port drivers
> + * can also inform the alternate mode drivers with this function that the mode
> + * was successfully exited.
> + */
> +int typec_altmode_exit(struct typec_altmode *adev)
> +{
> +	struct altmode *partner = to_altmode(adev)->partner;
> +	struct typec_port *port = typec_altmode2port(adev);
> +	struct typec_altmode *pdev = &partner->adev;
> +	int ret;
> +
> +	/* In case of port, just calling the driver and exiting */
> +	if (is_typec_port(adev->dev.parent)) {
> +		typec_altmode_update_active(pdev, pdev->mode, false);
> +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> +
> +		if (partner->ops && partner->ops->exit)
> +			partner->ops->exit(pdev);
> +		return 0;
> +	}
> +
> +	/* Moving to USB Safe State */
> +	ret = typec_set_mode(port, TYPEC_STATE_SAFE);
> +	if (ret)
> +		return ret;
> +
> +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> +
> +	/* Exit Mode command */
> +	if (partner->ops && partner->ops->exit)
> +		partner->ops->exit(pdev);
> +
> +	/* Back to USB operation */
> +	ret = typec_set_mode(port, TYPEC_STATE_USB);
> +	if (ret)
> +		return ret;
> +
> +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_USB, NULL);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_exit);
> +
> +/**
> + * typec_altmode_attention - Attention command
> + * @adev: The alternate mode
> + * @vdo: VDO for the Attention command
> + *
> + * Notifies the partner of @adev about Attention command.
> + */
> +void typec_altmode_attention(struct typec_altmode *adev, const u32 vdo)
> +{
> +	struct altmode *partner = to_altmode(adev)->partner;
> +
> +	if (partner && partner->ops && partner->ops->attention)
> +		partner->ops->attention(&partner->adev, vdo);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_attention);
> +
> +/**
> + * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
> + * @adev: Alternate mode handle
> + * @header: VDM Header
> + * @vdo: Array of Vendor Defined Data Objects
> + * @count: Number of Data Objects
> + *
> + * The alternate mode drivers use this function for SVID specific communication
> + * with the partner. The port drivers use it to deliver the Structured VDMs
> + * received from the partners to the alternate mode drivers.
> + */
> +int typec_altmode_vdm(struct typec_altmode *adev,
> +		      const u32 header, const u32 *vdo, int count)
> +{
> +	struct altmode *altmode;
> +	struct altmode *partner;
> +
> +	if (!adev)
> +		return 0;
> +
> +	altmode = to_altmode(adev);
> +
> +	if (!altmode->partner)
> +		return -ENODEV;
> +
> +	partner = altmode->partner;
> +
> +	if (partner->ops && partner->ops->vdm)
> +		return partner->ops->vdm(&partner->adev, header, vdo, count);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_vdm);
> +
> +void typec_altmode_register_ops(struct typec_altmode *adev,
> +				const struct typec_altmode_ops *ops)
> +{
> +	to_altmode(adev)->ops = ops;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_register_ops);
> +
> +/* -------------------------------------------------------------------------- */
> +/* API for the alternate mode drivers */
> +
> +/**
> + * typec_altmode_get_plug - Find cable plug alternate mode
> + * @adev: Handle to partner alternate mode
> + * @index: Cable plug index
> + *
> + * Increment reference count for cable plug alternate mode device. Returns
> + * handle to the cable plug alternate mode, or NULL if none is found.
> + */
> +struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
> +					     int index)
> +{
> +	struct altmode *port = to_altmode(adev)->partner;
> +
> +	if (port->plug[index]) {
> +		get_device(&port->plug[index]->adev.dev);
> +		return &port->plug[index]->adev;
> +	}
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
> +
> +/**
> + * typec_altmode_get_plug - Decrement cable plug alternate mode reference count

typec_altmode_put_plug

> + * @plug: Handle to the cable plug alternate mode
> + */
> +void typec_altmode_put_plug(struct typec_altmode *plug)
> +{
> +	if (plug)
> +		put_device(&plug->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_put_plug);
> +
> +int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
> +				    struct module *module)
> +{
> +	if (!drv->probe)
> +		return -EINVAL;
> +
> +	drv->driver.owner = module;
> +	drv->driver.bus = &typec_bus;
> +
> +	return driver_register(&drv->driver);
> +}
> +EXPORT_SYMBOL_GPL(__typec_altmode_register_driver);
> +
> +void typec_altmode_unregister_driver(struct typec_altmode_driver *drv)
> +{
> +	driver_unregister(&drv->driver);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_unregister_driver);
> +
> +/* -------------------------------------------------------------------------- */
> +/* API for the port drivers */
> +
> +bool typec_altmode_ufp_capable(struct typec_altmode *adev)
> +{
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	if (!is_typec_port(adev->dev.parent))
> +		return false;
> +
> +	return !(altmode->roles == TYPEC_PORT_DFP);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_ufp_capable);
> +
> +bool typec_altmode_dfp_capable(struct typec_altmode *adev)
> +{
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	if (!is_typec_port(adev->dev.parent))
> +		return false;
> +
> +	return !(altmode->roles == TYPEC_PORT_UFP);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_dfp_capable);
> +
> +/**
> + * typec_match_altmode - Match SVID to an array of alternate modes
> + * @altmodes: Array of alternate modes
> + * @n: Number of elements in the array, or -1 for NULL termiated arrays
> + * @svid: Standard or Vendor ID to match with
> + *
> + * Return pointer to an alternate mode with SVID mathing @svid, or NULL when no
> + * match is found.
> + */
> +struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
> +					  size_t n, u16 svid, u8 mode)
> +{
> +	int i;
> +
> +	for (i = 0; i < n; i++) {
> +		if (!altmodes[i])
> +			break;
> +		if (altmodes[i]->svid == svid && altmodes[i]->mode == mode)
> +			return altmodes[i];
> +	}
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(typec_match_altmode);
> +
> +/* -------------------------------------------------------------------------- */
> +
> +static ssize_t
> +description_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct typec_altmode *alt = to_typec_altmode(dev);
> +
> +	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
> +}
> +static DEVICE_ATTR_RO(description);
> +
> +static struct attribute *typec_attrs[] = {
> +	&dev_attr_description.attr,
> +	NULL
> +};
> +ATTRIBUTE_GROUPS(typec);
> +
> +static int typec_match(struct device *dev, struct device_driver *driver)
> +{
> +	struct typec_altmode_driver *drv = to_altmode_driver(driver);
> +	struct typec_altmode *altmode = to_typec_altmode(dev);
> +	const struct typec_device_id *id;
> +
> +	for (id = drv->id_table; id->svid; id++)
> +		if ((id->svid == altmode->svid) &&
> +		    (id->mode == TYPEC_ANY_MODE || id->mode == altmode->mode))
> +			return 1;
> +	return 0;
> +}
> +
> +static int typec_uevent(struct device *dev, struct kobj_uevent_env *env)
> +{
> +	struct typec_altmode *altmode = to_typec_altmode(dev);
> +
> +	if (add_uevent_var(env, "SVID=%04X", altmode->svid))
> +		return -ENOMEM;
> +
> +	if (add_uevent_var(env, "MODE=%u", altmode->mode))
> +		return -ENOMEM;
> +
> +	return add_uevent_var(env, "MODALIAS=typec:id%04Xm%02X",
> +			      altmode->svid, altmode->mode);
> +}
> +
> +static int typec_altmode_create_links(struct altmode *alt)
> +{
> +	struct device *port_dev = &alt->partner->adev.dev;
> +	struct device *dev = &alt->adev.dev;
> +	int err;
> +
> +	err = sysfs_create_link(&dev->kobj, &port_dev->kobj, "port");
> +	if (err)
> +		return err;
> +
> +	err = sysfs_create_link(&port_dev->kobj, &dev->kobj, "partner");
> +	if (err)
> +		sysfs_remove_link(&dev->kobj, "port");
> +
> +	return err;
> +}
> +
> +static int typec_probe(struct device *dev)
> +{
> +	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	/* Fail if the port does not support the alternate mode */
> +	if (!altmode->partner)
> +		return -ENODEV;
> +
> +	if (typec_altmode_create_links(altmode))
> +		dev_warn(dev, "failed to create symlinks\n");
> +
> +	return drv->probe(adev, altmode->partner->adev.vdo);
> +}
> +
> +static int typec_remove(struct device *dev)
> +{
> +	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	if (!is_typec_port(adev->dev.parent)) {
> +		sysfs_remove_link(&altmode->partner->adev.dev.kobj, "partner");
> +		sysfs_remove_link(&adev->dev.kobj, "port");
> +	}
> +
> +	if (drv->remove)
> +		drv->remove(to_typec_altmode(dev));
> +
> +	if (adev->active)
> +		typec_altmode_exit(adev);
> +
> +	return 0;
> +}
> +
> +struct bus_type typec_bus = {
> +	.name = "typec",
> +	.dev_groups = typec_groups,
> +	.match = typec_match,
> +	.uevent = typec_uevent,
> +	.probe = typec_probe,
> +	.remove = typec_remove,
> +};
> diff --git a/drivers/usb/typec/bus.h b/drivers/usb/typec/bus.h
> new file mode 100644
> index 000000000000..38585363952f
> --- /dev/null
> +++ b/drivers/usb/typec/bus.h
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __USB_TYPEC_ALTMODE_H__
> +#define __USB_TYPEC_ALTMODE_H__
> +
> +#include <linux/usb/typec.h>
> +
> +struct bus_type;
> +
> +struct altmode {
> +	unsigned int			id;
> +	struct typec_altmode		adev;
> +
> +	enum typec_port_data		roles;
> +
> +	struct attribute		*attrs[5];
> +	char				group_name[6];
> +	struct attribute_group		group;
> +	const struct attribute_group	*groups[2];
> +
> +	struct altmode			*partner;
> +	struct altmode			*plug[2];
> +	const struct typec_altmode_ops	*ops;
> +
> +	struct blocking_notifier_head	nh;
> +};
> +
> +#define to_altmode(d) container_of(d, struct altmode, adev)
> +
> +extern struct bus_type typec_bus;
> +extern const struct device_type typec_altmode_dev_type;
> +extern const struct device_type typec_port_dev_type;
> +
> +#define is_typec_altmode(_dev_) (_dev_->type == &typec_altmode_dev_type)
> +#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
> +
> +#endif /* __USB_TYPEC_ALTMODE_H__ */
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 26eeab1491b7..33fffb853994 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -6,6 +6,7 @@
>   * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
>   */
>  
> +#include <linux/connection.h>
>  #include <linux/device.h>
>  #include <linux/module.h>
>  #include <linux/mutex.h>
> @@ -13,25 +14,12 @@
>  #include <linux/usb/typec.h>
>  #include <linux/usb/typec_mux.h>
>  
> -struct typec_altmode {
> -	struct device			dev;
> -	u16				svid;
> -	u8				mode;
> -
> -	u32				vdo;
> -	char				*desc;
> -	enum typec_port_type		roles;
> -	unsigned int			active:1;
> -
> -	struct attribute		*attrs[5];
> -	char				group_name[6];
> -	struct attribute_group		group;
> -	const struct attribute_group	*groups[2];
> -};
> +#include "bus.h"
>  
>  struct typec_plug {
>  	struct device			dev;
>  	enum typec_plug_index		index;
> +	struct ida			mode_ids;
>  };
>  
>  struct typec_cable {
> @@ -46,11 +34,13 @@ struct typec_partner {
>  	unsigned int			usb_pd:1;
>  	struct usb_pd_identity		*identity;
>  	enum typec_accessory		accessory;
> +	struct ida			mode_ids;
>  };
>  
>  struct typec_port {
>  	unsigned int			id;
>  	struct device			dev;
> +	struct ida			mode_ids;
>  
>  	int				prefer_role;
>  	enum typec_data_role		data_role;
> @@ -71,17 +61,14 @@ struct typec_port {
>  #define to_typec_plug(_dev_) container_of(_dev_, struct typec_plug, dev)
>  #define to_typec_cable(_dev_) container_of(_dev_, struct typec_cable, dev)
>  #define to_typec_partner(_dev_) container_of(_dev_, struct typec_partner, dev)
> -#define to_altmode(_dev_) container_of(_dev_, struct typec_altmode, dev)
>  
>  static const struct device_type typec_partner_dev_type;
>  static const struct device_type typec_cable_dev_type;
>  static const struct device_type typec_plug_dev_type;
> -static const struct device_type typec_port_dev_type;
>  
>  #define is_typec_partner(_dev_) (_dev_->type == &typec_partner_dev_type)
>  #define is_typec_cable(_dev_) (_dev_->type == &typec_cable_dev_type)
>  #define is_typec_plug(_dev_) (_dev_->type == &typec_plug_dev_type)
> -#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
>  
>  static DEFINE_IDA(typec_index_ida);
>  static struct class *typec_class;
> @@ -163,27 +150,141 @@ static void typec_report_identity(struct device *dev)
>  /* ------------------------------------------------------------------------- */
>  /* Alternate Modes */
>  
> +static int altmode_match(struct device *dev, void *data)
> +{
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct typec_device_id *id = data;
> +
> +	if (!is_typec_altmode(dev))
> +		return 0;
> +
> +	return ((adev->svid == id->svid) && (adev->mode == id->mode));
> +}
> +
> +static void typec_altmode_get_partner(struct altmode *altmode)
> +{
> +	struct typec_altmode *adev = &altmode->adev;
> +	struct typec_device_id id = { adev->svid, adev->mode, };
> +	struct typec_port *port = typec_altmode2port(adev);
> +	struct altmode *partner;
> +	struct device *dev;
> +
> +	dev = device_find_child(&port->dev, &id, altmode_match);
> +	if (!dev)
> +		return;
> +
> +	/* Bind the port alt mode to the partner/plug alt mode. */
> +	partner = to_altmode(to_typec_altmode(dev));
> +	altmode->partner = partner;
> +
> +	/* Bind the partner/plug alt mode to the port alt mode. */
> +	if (is_typec_plug(adev->dev.parent)) {
> +		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
> +
> +		partner->plug[plug->index] = altmode;
> +	} else {
> +		partner->partner = altmode;
> +	}
> +}
> +
> +static void typec_altmode_put_partner(struct altmode *altmode)
> +{
> +	struct altmode *partner = altmode->partner;
> +	struct typec_altmode *adev;
> +
> +	if (!partner)
> +		return;
> +
> +	adev = &partner->adev;
> +
> +	if (is_typec_plug(adev->dev.parent)) {
> +		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
> +
> +		partner->plug[plug->index] = NULL;
> +	} else {
> +		partner->partner = NULL;
> +	}
> +	put_device(&adev->dev);
> +}
> +
> +static int __typec_port_match(struct device *dev, const void *name)
> +{
> +	return !strcmp((const char *)name, dev_name(dev));
> +}
> +
> +static void *typec_port_match(struct devcon *con, int ep, void *data)
> +{
> +	return class_find_device(typec_class, NULL, con->endpoint[ep],
> +				 __typec_port_match);
> +}
> +
> +struct typec_altmode *
> +typec_altmode_register_notifier(struct device *dev, u16 svid, u8 mode,
> +				struct notifier_block *nb)
> +{
> +	struct typec_device_id id = { svid, mode, };
> +	struct device *altmode_dev;
> +	struct device *port_dev;
> +	struct altmode *altmode;
> +	int ret;
> +
> +	/* Find the port linked to the caller */
> +	port_dev = __device_find_connection(dev, NULL, NULL, typec_port_match);
> +	if (!port_dev)
> +		return ERR_PTR(-ENODEV);
> +
> +	/* Find the altmode with matching svid */
> +	altmode_dev = device_find_child(port_dev, &id, altmode_match);
> +
> +	put_device(port_dev);
> +
> +	if (!altmode_dev)
> +		return ERR_PTR(-ENODEV);
> +
> +	altmode = to_altmode(to_typec_altmode(altmode_dev));
> +
> +	/* Register notifier */
> +	ret = blocking_notifier_chain_register(&altmode->nh, nb);
> +	if (ret) {
> +		put_device(altmode_dev);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return &altmode->adev;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_register_notifier);
> +
> +void typec_altmode_unregister_notifier(struct typec_altmode *adev,
> +				       struct notifier_block *nb)
> +{
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	blocking_notifier_chain_unregister(&altmode->nh, nb);
> +	put_device(&adev->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_unregister_notifier);
> +
>  /**
>   * typec_altmode_update_active - Report Enter/Exit mode
> - * @alt: Handle to the alternate mode
> + * @adev: Handle to the alternate mode
>   * @mode: Mode index
>   * @active: True when the mode has been entered
>   *
>   * If a partner or cable plug executes Enter/Exit Mode command successfully, the
>   * drivers use this routine to report the updated state of the mode.
>   */
> -void typec_altmode_update_active(struct typec_altmode *alt, int mode,
> +void typec_altmode_update_active(struct typec_altmode *adev, int mode,
>  				 bool active)
>  {
>  	char dir[6];
>  
> -	if (alt->active == active)
> +	if (adev->active == active)
>  		return;
>  
> -	alt->active = active;
> +	adev->active = active;
>  	snprintf(dir, sizeof(dir), "mode%d", mode);
> -	sysfs_notify(&alt->dev.kobj, dir, "active");
> -	kobject_uevent(&alt->dev.kobj, KOBJ_CHANGE);
> +	sysfs_notify(&adev->dev.kobj, dir, "active");
> +	kobject_uevent(&adev->dev.kobj, KOBJ_CHANGE);
>  }
>  EXPORT_SYMBOL_GPL(typec_altmode_update_active);
>  
> @@ -210,7 +311,7 @@ EXPORT_SYMBOL_GPL(typec_altmode2port);
>  static ssize_t
>  vdo_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *alt = to_typec_altmode(dev);
>  
>  	return sprintf(buf, "0x%08x\n", alt->vdo);
>  }
> @@ -219,7 +320,7 @@ static DEVICE_ATTR_RO(vdo);
>  static ssize_t
>  description_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *alt = to_typec_altmode(dev);
>  
>  	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
>  }
> @@ -228,28 +329,46 @@ static DEVICE_ATTR_RO(description);
>  static ssize_t
>  active_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *alt = to_typec_altmode(dev);
>  
>  	return sprintf(buf, "%s\n", alt->active ? "yes" : "no");
>  }
>  
> -static ssize_t
> -active_store(struct device *dev, struct device_attribute *attr,
> -			   const char *buf, size_t size)
> +static ssize_t active_store(struct device *dev, struct device_attribute *attr,
> +			    const char *buf, size_t size)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> -	struct typec_port *port = typec_altmode2port(alt);
> -	bool activate;
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct typec_port *port = typec_altmode2port(adev);
> +	struct altmode *altmode = to_altmode(adev);
> +	bool enter;
>  	int ret;
>  
>  	if (!port->cap->activate_mode)
>  		return -EOPNOTSUPP;
>  
> -	ret = kstrtobool(buf, &activate);
> +	ret = kstrtobool(buf, &enter);
>  	if (ret)
>  		return ret;
>  
> -	ret = port->cap->activate_mode(port->cap, alt->mode, activate);
> +	if (adev->active == enter)
> +		return size;
> +
> +	if (is_typec_port(adev->dev.parent)) {
> +		typec_altmode_update_active(adev, adev->mode, enter);
> +		sysfs_notify(&adev->dev.kobj, NULL, "active");
> +
> +		if (!altmode->partner)
> +			return size;
> +	} else {
> +		adev = &altmode->partner->adev;
> +
> +		if (!adev->active) {
> +			dev_warn(dev, "port has the mode disabled\n");
> +			return -EPERM;
> +		}
> +	}
> +
> +	ret = port->cap->activate_mode(adev, enter);
>  	if (ret)
>  		return ret;
>  
> @@ -261,7 +380,7 @@ static ssize_t
>  supported_roles_show(struct device *dev, struct device_attribute *attr,
>  		     char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct altmode *alt = to_altmode(to_typec_altmode(dev));
>  	ssize_t ret;
>  
>  	switch (alt->roles) {
> @@ -280,29 +399,72 @@ supported_roles_show(struct device *dev, struct device_attribute *attr,
>  }
>  static DEVICE_ATTR_RO(supported_roles);
>  
> -static void typec_altmode_release(struct device *dev)
> +static ssize_t
> +mode_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
>  
> -	kfree(alt);
> +	return sprintf(buf, "%u\n", adev->mode);
>  }
> +static DEVICE_ATTR_RO(mode);
>  
> -static ssize_t svid_show(struct device *dev, struct device_attribute *attr,
> -			 char *buf)
> +static ssize_t
> +svid_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
>  
> -	return sprintf(buf, "%04x\n", alt->svid);
> +	return sprintf(buf, "%04x\n", adev->svid);
>  }
>  static DEVICE_ATTR_RO(svid);
>  
>  static struct attribute *typec_altmode_attrs[] = {
> +	&dev_attr_active.attr,
> +	&dev_attr_mode.attr,
>  	&dev_attr_svid.attr,
> +	&dev_attr_vdo.attr,
>  	NULL
>  };
>  ATTRIBUTE_GROUPS(typec_altmode);
>  
> -static const struct device_type typec_altmode_dev_type = {
> +static int altmode_id_get(struct device *dev)
> +{
> +	struct ida *ids;
> +
> +	if (is_typec_partner(dev))
> +		ids = &to_typec_partner(dev)->mode_ids;
> +	else if (is_typec_plug(dev))
> +		ids = &to_typec_plug(dev)->mode_ids;
> +	else
> +		ids = &to_typec_port(dev)->mode_ids;
> +
> +	return ida_simple_get(ids, 0, 0, GFP_KERNEL);
> +}
> +
> +static void altmode_id_remove(struct device *dev, int id)
> +{
> +	struct ida *ids;
> +
> +	if (is_typec_partner(dev))
> +		ids = &to_typec_partner(dev)->mode_ids;
> +	else if (is_typec_plug(dev))
> +		ids = &to_typec_plug(dev)->mode_ids;
> +	else
> +		ids = &to_typec_port(dev)->mode_ids;
> +
> +	ida_simple_remove(ids, id);
> +}
> +
> +static void typec_altmode_release(struct device *dev)
> +{
> +	struct altmode *alt = to_altmode(to_typec_altmode(dev));
> +
> +	typec_altmode_put_partner(alt);
> +
> +	altmode_id_remove(alt->adev.dev.parent, alt->id);
> +	kfree(alt);
> +}
> +
> +const struct device_type typec_altmode_dev_type = {
>  	.name = "typec_alternate_mode",
>  	.groups = typec_altmode_groups,
>  	.release = typec_altmode_release,
> @@ -312,58 +474,72 @@ static struct typec_altmode *
>  typec_register_altmode(struct device *parent,
>  		       const struct typec_altmode_desc *desc)
>  {
> -	struct typec_altmode *alt;
> +	unsigned int id = altmode_id_get(parent);
> +	bool is_port = is_typec_port(parent);
> +	struct altmode *alt;
>  	int ret;
>  
>  	alt = kzalloc(sizeof(*alt), GFP_KERNEL);
>  	if (!alt)
>  		return ERR_PTR(-ENOMEM);
>  
> -	alt->svid = desc->svid;
> -	alt->mode = desc->mode;
> -	alt->vdo = desc->vdo;
> +	alt->adev.svid = desc->svid;
> +	alt->adev.mode = desc->mode;
> +	alt->adev.vdo = desc->vdo;
>  	alt->roles = desc->roles;
> +	alt->id = id;
>  
>  	alt->attrs[0] = &dev_attr_vdo.attr;
>  	alt->attrs[1] = &dev_attr_description.attr;
>  	alt->attrs[2] = &dev_attr_active.attr;
>  
> -	if (is_typec_port(parent))
> +	if (is_port) {
>  		alt->attrs[3] = &dev_attr_supported_roles.attr;
> +		alt->adev.active = true; /* Enabled by default */
> +	}
>  
>  	sprintf(alt->group_name, "mode%d", desc->mode);
>  	alt->group.name = alt->group_name;
>  	alt->group.attrs = alt->attrs;
>  	alt->groups[0] = &alt->group;
>  
> -	alt->dev.parent = parent;
> -	alt->dev.groups = alt->groups;
> -	alt->dev.type = &typec_altmode_dev_type;
> -	dev_set_name(&alt->dev, "%s-%04x:%u", dev_name(parent),
> -		     alt->svid, alt->mode);
> +	alt->adev.dev.parent = parent;
> +	alt->adev.dev.groups = alt->groups;
> +	alt->adev.dev.type = &typec_altmode_dev_type;
> +	dev_set_name(&alt->adev.dev, "%s.%u", dev_name(parent), id);
> +
> +	/* Link partners and plugs with the ports */
> +	if (is_port)
> +		BLOCKING_INIT_NOTIFIER_HEAD(&alt->nh);
> +	else
> +		typec_altmode_get_partner(alt);
>  
> -	ret = device_register(&alt->dev);
> +	/* The partners are bind to drivers */
> +	if (is_typec_partner(parent))
> +		alt->adev.dev.bus = &typec_bus;
> +
> +	ret = device_register(&alt->adev.dev);
>  	if (ret) {
>  		dev_err(parent, "failed to register alternate mode (%d)\n",
>  			ret);
> -		put_device(&alt->dev);
> +		put_device(&alt->adev.dev);
>  		return ERR_PTR(ret);
>  	}
>  
> -	return alt;
> +	return &alt->adev;
>  }
>  
>  /**
>   * typec_unregister_altmode - Unregister Alternate Mode
> - * @alt: The alternate mode to be unregistered
> + * @adev: The alternate mode to be unregistered
>   *
>   * Unregister device created with typec_partner_register_altmode(),
>   * typec_plug_register_altmode() or typec_port_register_altmode().
>   */
> -void typec_unregister_altmode(struct typec_altmode *alt)
> +void typec_unregister_altmode(struct typec_altmode *adev)
>  {
> -	if (!IS_ERR_OR_NULL(alt))
> -		device_unregister(&alt->dev);
> +	if (!IS_ERR_OR_NULL(adev))
> +		device_unregister(&adev->dev);
>  }
>  EXPORT_SYMBOL_GPL(typec_unregister_altmode);
>  
> @@ -401,6 +577,7 @@ static void typec_partner_release(struct device *dev)
>  {
>  	struct typec_partner *partner = to_typec_partner(dev);
>  
> +	ida_destroy(&partner->mode_ids);
>  	kfree(partner);
>  }
>  
> @@ -466,6 +643,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
>  	if (!partner)
>  		return ERR_PTR(-ENOMEM);
>  
> +	ida_init(&partner->mode_ids);
>  	partner->usb_pd = desc->usb_pd;
>  	partner->accessory = desc->accessory;
>  
> @@ -514,6 +692,7 @@ static void typec_plug_release(struct device *dev)
>  {
>  	struct typec_plug *plug = to_typec_plug(dev);
>  
> +	ida_destroy(&plug->mode_ids);
>  	kfree(plug);
>  }
>  
> @@ -566,6 +745,7 @@ struct typec_plug *typec_register_plug(struct typec_cable *cable,
>  
>  	sprintf(name, "plug%d", desc->index);
>  
> +	ida_init(&plug->mode_ids);
>  	plug->index = desc->index;
>  	plug->dev.class = typec_class;
>  	plug->dev.parent = &cable->dev;
> @@ -1080,12 +1260,13 @@ static void typec_release(struct device *dev)
>  	struct typec_port *port = to_typec_port(dev);
>  
>  	ida_simple_remove(&typec_index_ida, port->id);
> +	ida_destroy(&port->mode_ids);
>  	typec_switch_put(port->sw);
>  	typec_mux_put(port->mux);
>  	kfree(port);
>  }
>  
> -static const struct device_type typec_port_dev_type = {
> +const struct device_type typec_port_dev_type = {
>  	.name = "typec_port",
>  	.groups = typec_groups,
>  	.uevent = typec_uevent,
> @@ -1238,6 +1419,8 @@ EXPORT_SYMBOL_GPL(typec_set_mode);
>   * typec_port_register_altmode - Register USB Type-C Port Alternate Mode
>   * @port: USB Type-C Port that supports the alternate mode
>   * @desc: Description of the alternate mode
> + * @ops: Port specific operations for the alternate mode
> + * @drvdata: Private pointer to driver specific info
>   *
>   * This routine is used to register an alternate mode that @port is capable of
>   * supporting.
> @@ -1322,10 +1505,12 @@ struct typec_port *typec_register_port(struct device *parent,
>  		break;
>  	}
>  
> +	ida_init(&port->mode_ids);
> +	mutex_init(&port->port_type_lock);
> +
>  	port->id = id;
>  	port->cap = cap;
>  	port->port_type = cap->type;
> -	mutex_init(&port->port_type_lock);
>  	port->prefer_role = cap->prefer_role;
>  
>  	port->dev.class = typec_class;
> @@ -1369,8 +1554,19 @@ EXPORT_SYMBOL_GPL(typec_unregister_port);
>  
>  static int __init typec_init(void)
>  {
> +	int ret;
> +
> +	ret = bus_register(&typec_bus);
> +	if (ret)
> +		return ret;
> +
>  	typec_class = class_create(THIS_MODULE, "typec");
> -	return PTR_ERR_OR_ZERO(typec_class);
> +	if (IS_ERR(typec_class)) {
> +		bus_unregister(&typec_bus);
> +		return PTR_ERR(typec_class);
> +	}
> +
> +	return 0;
>  }
>  subsys_initcall(typec_init);
>  
> @@ -1378,6 +1574,7 @@ static void __exit typec_exit(void)
>  {
>  	class_destroy(typec_class);
>  	ida_destroy(&typec_index_ida);
> +	bus_unregister(&typec_bus);
>  }
>  module_exit(typec_exit);
>  
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 48fb2b43c35a..17c1a912f524 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -733,4 +733,19 @@ struct tb_service_id {
>  #define TBSVC_MATCH_PROTOCOL_VERSION	0x0004
>  #define TBSVC_MATCH_PROTOCOL_REVISION	0x0008
>  
> +/* USB Type-C Alternate Modes */
> +
> +#define TYPEC_ANY_MODE	0x7
> +
> +/**
> + * struct typec_device_id - USB Type-C alternate mode identifiers
> + * @svid: Standard or Vendor ID
> + * @mode: Mode index
> + */
> +struct typec_device_id {
> +	__u16 svid;
> +	__u8 mode;
> +	kernel_ulong_t driver_data;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
> index 278b6b42c7ea..a19aa3db4272 100644
> --- a/include/linux/usb/typec.h
> +++ b/include/linux/usb/typec.h
> @@ -4,16 +4,13 @@
>  #define __LINUX_USB_TYPEC_H
>  
>  #include <linux/types.h>
> -
> -/* XXX: Once we have a header for USB Power Delivery, this belongs there */
> -#define ALTMODE_MAX_MODES	6
> +#include <linux/usb/typec_altmode.h>
>  
>  /* USB Type-C Specification releases */
>  #define USB_TYPEC_REV_1_0	0x100 /* 1.0 */
>  #define USB_TYPEC_REV_1_1	0x110 /* 1.1 */
>  #define USB_TYPEC_REV_1_2	0x120 /* 1.2 */
>  
> -struct typec_altmode;
>  struct typec_partner;
>  struct typec_cable;
>  struct typec_plug;
> @@ -107,7 +104,7 @@ struct typec_altmode_desc {
>  	u8			mode;
>  	u32			vdo;
>  	/* Only used with ports */
> -	enum typec_port_type	roles;
> +	enum typec_port_data	roles;
>  };
>  
>  struct typec_altmode
> @@ -118,7 +115,8 @@ struct typec_altmode
>  			     const struct typec_altmode_desc *desc);
>  struct typec_altmode
>  *typec_port_register_altmode(struct typec_port *port,
> -			     const struct typec_altmode_desc *desc);
> +			    const struct typec_altmode_desc *desc);
> +
>  void typec_unregister_altmode(struct typec_altmode *altmode);
>  
>  struct typec_port *typec_altmode2port(struct typec_altmode *alt);
> @@ -213,12 +211,10 @@ struct typec_capability {
>  				  enum typec_role);
>  	int		(*vconn_set)(const struct typec_capability *,
>  				     enum typec_role);
> -
> -	int		(*activate_mode)(const struct typec_capability *,
> -					 int mode, int activate);
>  	int		(*port_type_set)(const struct typec_capability *,
> -					enum typec_port_type);
> +					 enum typec_port_type);
>  
> +	int		(*activate_mode)(struct typec_altmode *alt, int active);
>  };
>  
>  /* Specific to try_role(). Indicates the user want's to clear the preference. */
> diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
> new file mode 100644
> index 000000000000..bc765352a3c8
> --- /dev/null
> +++ b/include/linux/usb/typec_altmode.h
> @@ -0,0 +1,136 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __USB_TYPEC_ALTMODE_H
> +#define __USB_TYPEC_ALTMODE_H
> +
> +#include <linux/device.h>
> +#include <linux/mod_devicetable.h>
> +
> +#define MODE_DISCOVERY_MAX	6
> +
> +/**
> + * struct typec_altmode - USB Type-C alternate mode device
> + * @dev: Driver model's view of this device
> + * @svid: Standard or Vendor ID (SVID) of the alternate mode
> + * @mode: Index of the Mode
> + * @vdo: VDO returned by Discover Modes USB PD command
> + * @desc: Optional human readable description of the mode
> + * @active: Tells has the mode been entered or not
> + */
> +struct typec_altmode {
> +	struct device		dev;
> +	u16			svid;
> +	int			mode;
> +	u32			vdo;
> +	char			*desc;
> +	bool			active;
> +} __packed;
> +
> +#define to_typec_altmode(d) container_of(d, struct typec_altmode, dev)
> +
> +static inline void typec_altmode_set_drvdata(struct typec_altmode *altmode,
> +					     void *data)
> +{
> +	dev_set_drvdata(&altmode->dev, data);
> +}
> +
> +static inline void *typec_altmode_get_drvdata(struct typec_altmode *altmode)
> +{
> +	return dev_get_drvdata(&altmode->dev);
> +}
> +
> +/**
> + * struct typec_altmode_ops - Alternate mode specific operations vector
> + * @enter: Operations to be executed with Enter Mode Command
> + * @exit: Operations to be executed with Exit Mode Command
> + * @attention: Callback for Attention Command
> + * @vdm: Callback for SVID specific commands
> + * @notify: Communication channel for platform and the alternate mode
> + */
> +struct typec_altmode_ops {
> +	void (*enter)(struct typec_altmode *altmode);
> +	void (*exit)(struct typec_altmode *altmode);
> +	void (*attention)(struct typec_altmode *altmode, const u32 vdo);
> +	int (*vdm)(struct typec_altmode *altmode, const u32 hdr,
> +		   const u32 *vdo, int cnt);
> +	int (*notify)(struct typec_altmode *altmode, unsigned long conf,
> +		      void *data);
> +};
> +
> +void typec_altmode_register_ops(struct typec_altmode *altmode,
> +				const struct typec_altmode_ops *ops);
> +
> +int typec_altmode_enter(struct typec_altmode *altmode);
> +int typec_altmode_exit(struct typec_altmode *altmode);
> +void typec_altmode_attention(struct typec_altmode *altmode, const u32 vdo);
> +int typec_altmode_vdm(struct typec_altmode *altmode,
> +		      const u32 header, const u32 *vdo, int count);
> +int typec_altmode_notify(struct typec_altmode *altmode, unsigned long conf,
> +			 void *data);
> +
> +/* Return values for type_altmode_vdm() */
> +#define VDM_DONE		0 /* Don't care */
> +#define VDM_OK			1 /* Suits me */
> +
> +/*
> + * These are the pin states (USB, Safe and Alt Mode) and accessory modes (Audio
> + * and Debug) defined in USB Type-C Specification. SVID specific pin states are
> + * expected to follow and start from the value TYPEC_STATE_MODAL.
> + *
> + * Port drivers should use TYPEC_STATE_AUDIO and TYPEC_STATE_DEBUG as the
> + * operation value for typec_set_mode() when accessory modes are in use.
> + *
> + * NOTE: typec_altmode_notify() does not accept values smaller then
> + * TYPEC_STATE_MODAL. USB Type-C bus will follow USB Type-C Specification with
> + * TYPEC_STATE_USB and TYPEC_STATE_SAFE.
> + */
> +enum {
> +	TYPEC_STATE_USB,	/* USB Operation */
> +	TYPEC_STATE_AUDIO,	/* Audio Accessory */
> +	TYPEC_STATE_DEBUG,	/* Debug Accessory */
> +	TYPEC_STATE_SAFE,	/* USB Safe State */
> +	TYPEC_STATE_MODAL,	/* Alternate Modes */
> +};
> +
> +#define TYPEC_MODAL_STATE(_state_)	((_state_) + TYPEC_STATE_MODAL)
> +
> +struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *altmode,
> +					     int index);
> +void typec_altmode_put_plug(struct typec_altmode *plug);
> +
> +bool typec_altmode_ufp_capable(struct typec_altmode *altmode);
> +bool typec_altmode_dfp_capable(struct typec_altmode *altmode);
> +struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
> +					  size_t n, u16 svid, u8 mode);
> +
> +/**
> + * struct typec_altmode_driver - USB Type-C alternate mode device driver
> + * @id_table: Null terminated array of SVIDs
> + * @probe: Callback for device binding
> + * @remove: Callback for device unbinding
> + * @driver: Device driver model driver
> + *
> + * These drivers will be bind to the partner alternate mode devices. They will
> + * handle all SVID specific communication.
> + */
> +struct typec_altmode_driver {
> +	const struct typec_device_id *id_table;
> +	int (*probe)(struct typec_altmode *altmode, u32 port_vdo);
> +	void (*remove)(struct typec_altmode *altmode);
> +	struct device_driver driver;
> +};
> +
> +#define to_altmode_driver(d) container_of(d, struct typec_altmode_driver, \
> +					  driver)
> +
> +#define typec_altmode_register_driver(drv) \
> +		__typec_altmode_register_driver(drv, THIS_MODULE)
> +int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
> +				    struct module *module);
> +void typec_altmode_unregister_driver(struct typec_altmode_driver *drv);
> +
> +#define module_typec_altmode_driver(__typec_altmode_driver) \
> +	module_driver(__typec_altmode_driver, typec_altmode_register_driver, \
> +		      typec_altmode_unregister_driver)
> +
> +#endif /* __USB_TYPEC_ALTMODE_H */
> diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
> index 9fad6afe4c41..c48c7f56ae64 100644
> --- a/scripts/mod/devicetable-offsets.c
> +++ b/scripts/mod/devicetable-offsets.c
> @@ -218,5 +218,9 @@ int main(void)
>  	DEVID_FIELD(tb_service_id, protocol_version);
>  	DEVID_FIELD(tb_service_id, protocol_revision);
>  
> +	DEVID(typec_device_id);
> +	DEVID_FIELD(typec_device_id, svid);
> +	DEVID_FIELD(typec_device_id, mode);
> +
>  	return 0;
>  }
> diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
> index b9beeaa4695b..a8afba836409 100644
> --- a/scripts/mod/file2alias.c
> +++ b/scripts/mod/file2alias.c
> @@ -1341,6 +1341,19 @@ static int do_tbsvc_entry(const char *filename, void *symval, char *alias)
>  }
>  ADD_TO_DEVTABLE("tbsvc", tb_service_id, do_tbsvc_entry);
>  
> +/* Looks like: typec:idNmN */
> +static int do_typec_entry(const char *filename, void *symval, char *alias)
> +{
> +	DEF_FIELD(symval, typec_device_id, svid);
> +	DEF_FIELD(symval, typec_device_id, mode);
> +
> +	sprintf(alias, "typec:id%04X", svid);
> +	ADD(alias, "m", mode != TYPEC_ANY_MODE, mode);
> +
> +	return 1;
> +}
> +ADD_TO_DEVTABLE("typec", typec_device_id, do_typec_entry);
> +
>  /* Does namelen bytes of name exactly match the symbol? */
>  static bool sym_is(const char *name, unsigned namelen, const char *symbol)
>  {
> -- 
> 2.16.1
> 

[RFC,v2,2/3] usb: typec: Bus type for alternate modes

[Guenter Roeck]

On Fri, Mar 09, 2018 at 06:19:17PM +0300, Heikki Krogerus wrote:
> Introducing a simple bus for the alternate modes. Bus allows
> binding drivers to the discovered alternate modes the
> partners support.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  Documentation/ABI/obsolete/sysfs-class-typec |  48 +++
>  Documentation/ABI/testing/sysfs-bus-typec    |  51 ++++
>  Documentation/ABI/testing/sysfs-class-typec  |  62 +---
>  Documentation/driver-api/usb/typec_bus.rst   | 143 +++++++++
>  drivers/usb/typec/Makefile                   |   2 +-
>  drivers/usb/typec/bus.c                      | 421 +++++++++++++++++++++++++++
>  drivers/usb/typec/bus.h                      |  37 +++
>  drivers/usb/typec/class.c                    | 325 +++++++++++++++++----
>  include/linux/mod_devicetable.h              |  15 +
>  include/linux/usb/typec.h                    |  16 +-
>  include/linux/usb/typec_altmode.h            | 136 +++++++++
>  scripts/mod/devicetable-offsets.c            |   4 +
>  scripts/mod/file2alias.c                     |  13 +
>  13 files changed, 1138 insertions(+), 135 deletions(-)
>  create mode 100644 Documentation/ABI/obsolete/sysfs-class-typec
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-typec
>  create mode 100644 Documentation/driver-api/usb/typec_bus.rst
>  create mode 100644 drivers/usb/typec/bus.c
>  create mode 100644 drivers/usb/typec/bus.h
>  create mode 100644 include/linux/usb/typec_altmode.h
> 
> diff --git a/Documentation/ABI/obsolete/sysfs-class-typec b/Documentation/ABI/obsolete/sysfs-class-typec
> new file mode 100644
> index 000000000000..32623514ee87
> --- /dev/null
> +++ b/Documentation/ABI/obsolete/sysfs-class-typec
> @@ -0,0 +1,48 @@
> +These files are deprecated and will be removed. The same files are available
> +under /sys/bus/typec (see Documentation/ABI/testing/sysfs-bus-typec).
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		The SVID (Standard or Vendor ID) assigned by USB-IF for this
> +		alternate mode.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Every supported mode will have its own directory. The name of
> +		a mode will be "mode<index>" (for example mode1), where <index>
> +		is the actual index to the mode VDO returned by Discover Modes
> +		USB power delivery command.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows description of the mode. The description is optional for
> +		the drivers, just like with the Billboard Devices.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows the VDO in hexadecimal returned by Discover Modes command
> +		for this mode.
> +
> +What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
> +Date:		April 2017
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows if the mode is active or not. The attribute can be used
> +		for entering/exiting the mode with partners and cable plugs, and
> +		with the port alternate modes it can be used for disabling
> +		support for specific alternate modes. Entering/exiting modes is
> +		supported as synchronous operation so write(2) to the attribute
> +		does not return until the enter/exit mode operation has
> +		finished. The attribute is notified when the mode is
> +		entered/exited so poll(2) on the attribute wakes up.
> +		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
> +
> +		Valid values: yes, no
> diff --git a/Documentation/ABI/testing/sysfs-bus-typec b/Documentation/ABI/testing/sysfs-bus-typec
> new file mode 100644
> index 000000000000..ead63f97d9a2
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-typec
> @@ -0,0 +1,51 @@
> +What:		/sys/bus/typec/devices/.../active
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows if the mode is active or not. The attribute can be used
> +		for entering/exiting the mode. Entering/exiting modes is
> +		supported as synchronous operation so write(2) to the attribute
> +		does not return until the enter/exit mode operation has
> +		finished. The attribute is notified when the mode is
> +		entered/exited so poll(2) on the attribute wakes up.
> +		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
> +
> +		Valid values are boolean.
> +
> +What:		/sys/bus/typec/devices/.../description
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows description of the mode. The description is optional for
> +		the drivers, just like with the Billboard Devices.
> +
> +What:		/sys/bus/typec/devices/.../mode
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		The index number of the mode returned by Discover Modes USB
> +		Power Delivery command. Depending on the alternate mode, the
> +		mode index may be significant.
> +
> +		With some alternate modes (SVIDs), the mode index is assigned
> +		for specific functionality in the specification for that
> +		alternate mode.
> +
> +		With other alternate modes, the mode index values are not
> +		assigned, and can not be therefore used for identification. When
> +		the mode index is not assigned, identifying the alternate mode
> +		must be done with either mode VDO or the description.
> +
> +What:		/sys/bus/typec/devices/.../svid
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		The Standard or Vendor ID (SVID) assigned by USB-IF for this
> +		alternate mode.
> +
> +What:		/sys/bus/typec/devices/.../vdo
> +Date:		April 2018
> +Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> +Description:
> +		Shows the VDO in hexadecimal returned by Discover Modes command
> +		for this mode.
> diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
> index 5be552e255e9..d7647b258c3c 100644
> --- a/Documentation/ABI/testing/sysfs-class-typec
> +++ b/Documentation/ABI/testing/sysfs-class-typec
> @@ -222,70 +222,12 @@ Description:
>  		available. The value can be polled.
>  
>  
> -Alternate Mode devices.
> +USB Type-C port alternate mode devices.
>  
> -The alternate modes will have Standard or Vendor ID (SVID) assigned by USB-IF.
> -The ports, partners and cable plugs can have alternate modes. A supported SVID
> -will consist of a set of modes. Every SVID a port/partner/plug supports will
> -have a device created for it, and every supported mode for a supported SVID will
> -have its own directory under that device. Below <dev> refers to the device for
> -the alternate mode.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/svid
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		The SVID (Standard or Vendor ID) assigned by USB-IF for this
> -		alternate mode.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Every supported mode will have its own directory. The name of
> -		a mode will be "mode<index>" (for example mode1), where <index>
> -		is the actual index to the mode VDO returned by Discover Modes
> -		USB power delivery command.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/description
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Shows description of the mode. The description is optional for
> -		the drivers, just like with the Billboard Devices.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/vdo
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Shows the VDO in hexadecimal returned by Discover Modes command
> -		for this mode.
> -
> -What:		/sys/class/typec/<port|partner|cable>/<dev>/mode<index>/active
> -Date:		April 2017
> -Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
> -Description:
> -		Shows if the mode is active or not. The attribute can be used
> -		for entering/exiting the mode with partners and cable plugs, and
> -		with the port alternate modes it can be used for disabling
> -		support for specific alternate modes. Entering/exiting modes is
> -		supported as synchronous operation so write(2) to the attribute
> -		does not return until the enter/exit mode operation has
> -		finished. The attribute is notified when the mode is
> -		entered/exited so poll(2) on the attribute wakes up.
> -		Entering/exiting a mode will also generate uevent KOBJ_CHANGE.
> -
> -		Valid values: yes, no
> -
> -What:		/sys/class/typec/<port>/<dev>/mode<index>/supported_roles
> +What:		/sys/class/typec/<port>/<alt mode>/supported_roles
>  Date:		April 2017
>  Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
>  Description:
>  		Space separated list of the supported roles.
>  
> -		This attribute is available for the devices describing the
> -		alternate modes a port supports, and it will not be exposed with
> -		the devices presenting the alternate modes the partners or cable
> -		plugs support.
> -
>  		Valid values: source, sink
> diff --git a/Documentation/driver-api/usb/typec_bus.rst b/Documentation/driver-api/usb/typec_bus.rst
> new file mode 100644
> index 000000000000..ef3c049a8a7f
> --- /dev/null
> +++ b/Documentation/driver-api/usb/typec_bus.rst
> @@ -0,0 +1,143 @@
> +
> +API for USB Type-C Alternate Mode drivers
> +=========================================
> +
> +Introduction
> +------------
> +
> +Alternate modes require communication with the partner using Vendor Defined
> +Messages (VDM) as defined in USB Type-C and USB Power Delivery Specifications.
> +The communication is SVID (Standard or Vendor ID) specific, i.e. specific for
> +every alternate mode, so every alternate mode will need custom driver.
> +
> +USB Type-C bus allows binding a driver to the discovered partner alternate
> +modes by using the SVID and the mode number.
> +
> +USB Type-C Connector Class provides a device for every alternate mode a port
> +supports, and separate device for every alternate mode the partner supports.
> +The drivers for the alternate modes are bind to the partner alternate mode
> +devices, and the port alternate mode devices must be handled by the port
> +drivers.
> +
> +When a new partner alternate mode device is registered, it is linked to the
> +alternate mode device of the port that the partner is attached to, that has
> +matching SVID and mode. Communication between the port driver and alternate mode
> +driver will happen using the same API.
> +
> +The port alternate mode devices are used as a proxy between the partner and the
> +alternate mode drivers, so the port drivers are only expected to pass the SVID
> +specific commands from the alternate mode drivers to the partner, and from the
> +partners to the alternate mode drivers. No direct SVID specific communication is
> +needed from the port drivers, but the port drivers need to provide the operation
> +callbacks for the port alternate mode devices, just like the alternate mode
> +drivers need to provide them for the partner alternate mode devices.
> +
> +Usage:
> +------
> +
> +General
> +~~~~~~~
> +
> +By default, the alternate mode drivers are responsible for entering the mode.
> +It is also possible to leave the decision about entering the mode to the user
> +space (See Documentation/ABI/testing/sysfs-class-typec). Port drivers should not
> +enter any modes on their own.
> +
> +The alternate mode drivers need to register their operation vector in their
> +``->probe`` callback with :c:func:`typec_altmode_register_ops()`. They should
> +be registered before the mode is entered using :c:func:`typec_altmode_enter()`.
> +
> +``->vdm`` is the most important callback in the vector. It will be used to
> +deliver all the SVID specific commands from the partner to the alternate mode
> +driver, and vise versa in case of port drivers. The drivers send the SVID
> +specific commands to each other using :c:func:`typec_altmode_vmd()`.
> +
> +If the communication with the partner using the SVID specific commands results
> +in need to re-configure the pins on the connector, the alternate mode driver
> +needs to notify the bus using :c:func:`typec_altmode_notify()`. The driver
> +passes the negotiated SVID specific pin configuration value to the function as
> +parameter. The bus driver will then configure the mux behind the connector using
> +that value as the state value for the mux, and also call blocking notification
> +chain to notify the external drivers about the state of the connector that need
> +to know it.
> +
> +NOTE: The SVID specific pin configuration values must always start from
> +``TYPEC_STATE_MODAL``. USB Type-C specification defines two default states for
> +the connector: ``TYPEC_STATE_USB`` and ``TYPEC_STATE_SAFE``. USB Type-C
> +Specification also defines two Accessory modes, Audio and Debug:
> +``TYPEC_STATE_AUDIO`` and ``TYPEC_STATE_DEBUG`` These values are reserved by the
> +bus as the four first possible values for the state, and attempts to use them
> +from the alternate mode drivers will result in failure. When the alternate mode
> +is entered, the bus will put the connector into ``TYPEC_STATE_SAFE`` before
> +sending Enter or Exit Mode command as defined in USB Type-C Specification, and
> +also put the connector back to ``TYPEC_STATE_USB`` after the mode has been
> +exited.
> +
> +An example of working definitions for SVID specific pin configurations would
> +look like this:
> +
> +enum {
> +	ALTMODEX_CONF_A = TYPEC_STATE_MODAL,
> +	ALTMODEX_CONF_B,
> +	...
> +};
> +
> +Helper macro ``TYPEC_MODAL_STATE()`` can also be used:
> +
> +#define ALTMODEX_CONF_A = TYPEC_MODAL_STATE(0);
> +#define ALTMODEX_CONF_B = TYPEC_MODAL_STATE(1);
> +
> +Notification chain
> +~~~~~~~~~~~~~~~~~~
> +
> +The drivers for the components that the alternate modes are designed for need to
> +get details regarding the results of the negotiation with the partner, and the
> +pin configuration of the connector. In case of DisplayPort alternate mode for
> +example, the GPU drivers will need to know those details. In case of
> +Thunderbolt alternate mode, the thunderbolt drivers will need to know them, and
> +so on.
> +
> +The notification chain is designed for this purpose. The drivers can register
> +notifiers with :c:func:`typec_altmode_register_notifier()`.
> +
> +Cable plug alternate modes
> +~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +The alternate mode drivers are not bind to cable plug alternate mode devices,
> +only to the partner alternate mode devices. If the alternate mode supports, or
> +requires, a cable that responds to SOP Prime, and optionally SOP Double Prime
> +messages, the driver for that alternate mode must request handle to the cable
> +plug alternate modes using :c:func:`typec_altmode_get_plug()`, and taking over
> +their control.
> +
> +Driver API
> +----------
> +
> +Alternate mode driver registering/unregistering
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_altmode_register_driver typec_altmode_unregister_driver
> +
> +Alternate mode driver operations
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_altmode_register_ops typec_altmode_enter typec_altmode_exit typec_altmode_attention typec_altmode_vdm typec_altmode_notify
> +
> +API for the port drivers
> +~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_match_altmode
> +
> +Cable Plug operations
> +~~~~~~~~~~~~~~~~~~~~~
> +
> +.. kernel-doc:: drivers/usb/typec/bus.c
> +   :functions: typec_altmode_get_plug typec_altmode_put_plug
> +
> +Notifications
> +~~~~~~~~~~~~~
> +.. kernel-doc:: drivers/usb/typec/class.c
> +   :functions: typec_altmode_register_notifier typec_altmode_unregister_notifier
> diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
> index 1f599a6c30cc..5466c62c8e97 100644
> --- a/drivers/usb/typec/Makefile
> +++ b/drivers/usb/typec/Makefile
> @@ -1,6 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_TYPEC)		+= typec.o
> -typec-y				:= class.o mux.o
> +typec-y				:= class.o mux.o bus.o
>  obj-$(CONFIG_TYPEC_TCPM)	+= tcpm.o
>  obj-y				+= fusb302/
>  obj-$(CONFIG_TYPEC_WCOVE)	+= typec_wcove.o
> diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
> new file mode 100644
> index 000000000000..92944aaf3d6a
> --- /dev/null
> +++ b/drivers/usb/typec/bus.c
> @@ -0,0 +1,421 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * Bus for USB Type-C Alternate Modes
> + *
> + * Copyright (C) 2018 Intel Corporation
> + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> + */
> +
> +#include "bus.h"
> +
> +/* -------------------------------------------------------------------------- */
> +/* Common API */
> +
> +/**
> + * typec_altmode_notify - Communication between the OS and alternate mode driver
> + * @adev: Handle to the alternate mode
> + * @conf: Alternate mode specific configuration value
> + * @data: Alternate mode specific data
> + *
> + * The primary purpose for this function is to allow the alternate mode drivers
> + * to tell which pin configuration has been negotiated with the partner. That
> + * information will then be used for example to configure the muxes.
> + * Communication to the other direction is also possible, and low level device
> + * drivers can also send notifications to the alternate mode drivers. The actual
> + * communication will be specific for every SVID.
> + */
> +int typec_altmode_notify(struct typec_altmode *adev,
> +			 unsigned long conf, void *data)
> +{
> +	struct altmode *altmode;
> +	struct altmode *partner;
> +	int ret;
> +
> +	/*
> +	 * All SVID specific configuration values must start from
> +	 * TYPEC_STATE_MODAL. The first values are reserved for the pin states
> +	 * defined in USB Type-C specification: TYPEC_STATE_USB and
> +	 * TYPEC_STATE_SAFE. We'll follow this rule even with modes that do not
> +	 * require pin reconfiguration for the sake of simplicity.
> +	 */
> +	if (conf < TYPEC_STATE_MODAL)
> +		return -EINVAL;
> +
> +	if (!adev)
> +		return 0;
> +
> +	altmode = to_altmode(adev);
> +
> +	if (!altmode->partner)
> +		return -ENODEV;
> +
> +	ret = typec_set_mode(typec_altmode2port(adev), (int)conf);
> +	if (ret)
> +		return ret;
> +
> +	partner = altmode->partner;
> +
> +	blocking_notifier_call_chain(is_typec_port(adev->dev.parent) ?
> +				     &altmode->nh : &partner->nh,
> +				     conf, data);
> +
> +	if (partner->ops && partner->ops->notify)
> +		return partner->ops->notify(&partner->adev, conf, data);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_notify);
> +
> +/**
> + * typec_altmode_enter - Enter Mode
> + * @adev: The alternate mode
> + *
> + * The alternate mode drivers use this function to enter mode. The port drivers
> + * use this to inform the alternate mode drivers that their mode has been
> + * entered successfully.
> + */
> +int typec_altmode_enter(struct typec_altmode *adev)
> +{
> +	struct altmode *partner = to_altmode(adev)->partner;
> +	struct typec_altmode *pdev = &partner->adev;
> +	int ret;
> +
> +	if (is_typec_port(adev->dev.parent)) {
> +		typec_altmode_update_active(pdev, pdev->mode, true);
> +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> +		goto enter_mode;
> +	}
> +
> +	if (!pdev->active)
> +		return -EPERM;
> +
> +	/* First moving to USB Safe State */
> +	ret = typec_set_mode(typec_altmode2port(adev), TYPEC_STATE_SAFE);
> +	if (ret)
> +		return ret;
> +
> +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> +
> +enter_mode:
> +	/* Enter Mode command */
> +	if (partner->ops && partner->ops->enter)
> +		partner->ops->enter(pdev);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_enter);
> +
> +/**
> + * typec_altmode_enter - Exit Mode

typec_altmode_exit

> + * @adev: The alternate mode
> + *
> + * The alternate mode drivers use this function to exit mode. The port drivers
> + * can also inform the alternate mode drivers with this function that the mode
> + * was successfully exited.
> + */
> +int typec_altmode_exit(struct typec_altmode *adev)
> +{
> +	struct altmode *partner = to_altmode(adev)->partner;
> +	struct typec_port *port = typec_altmode2port(adev);
> +	struct typec_altmode *pdev = &partner->adev;
> +	int ret;
> +
> +	/* In case of port, just calling the driver and exiting */
> +	if (is_typec_port(adev->dev.parent)) {
> +		typec_altmode_update_active(pdev, pdev->mode, false);
> +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> +
> +		if (partner->ops && partner->ops->exit)
> +			partner->ops->exit(pdev);
> +		return 0;
> +	}
> +
> +	/* Moving to USB Safe State */
> +	ret = typec_set_mode(port, TYPEC_STATE_SAFE);
> +	if (ret)
> +		return ret;
> +
> +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> +
> +	/* Exit Mode command */
> +	if (partner->ops && partner->ops->exit)
> +		partner->ops->exit(pdev);
> +
> +	/* Back to USB operation */
> +	ret = typec_set_mode(port, TYPEC_STATE_USB);
> +	if (ret)
> +		return ret;
> +
> +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_USB, NULL);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_exit);
> +
> +/**
> + * typec_altmode_attention - Attention command
> + * @adev: The alternate mode
> + * @vdo: VDO for the Attention command
> + *
> + * Notifies the partner of @adev about Attention command.
> + */
> +void typec_altmode_attention(struct typec_altmode *adev, const u32 vdo)
> +{
> +	struct altmode *partner = to_altmode(adev)->partner;
> +
> +	if (partner && partner->ops && partner->ops->attention)
> +		partner->ops->attention(&partner->adev, vdo);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_attention);
> +
> +/**
> + * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
> + * @adev: Alternate mode handle
> + * @header: VDM Header
> + * @vdo: Array of Vendor Defined Data Objects
> + * @count: Number of Data Objects
> + *
> + * The alternate mode drivers use this function for SVID specific communication
> + * with the partner. The port drivers use it to deliver the Structured VDMs
> + * received from the partners to the alternate mode drivers.
> + */
> +int typec_altmode_vdm(struct typec_altmode *adev,
> +		      const u32 header, const u32 *vdo, int count)
> +{
> +	struct altmode *altmode;
> +	struct altmode *partner;
> +
> +	if (!adev)
> +		return 0;
> +
> +	altmode = to_altmode(adev);
> +
> +	if (!altmode->partner)
> +		return -ENODEV;
> +
> +	partner = altmode->partner;
> +
> +	if (partner->ops && partner->ops->vdm)
> +		return partner->ops->vdm(&partner->adev, header, vdo, count);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_vdm);
> +
> +void typec_altmode_register_ops(struct typec_altmode *adev,
> +				const struct typec_altmode_ops *ops)
> +{
> +	to_altmode(adev)->ops = ops;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_register_ops);
> +
> +/* -------------------------------------------------------------------------- */
> +/* API for the alternate mode drivers */
> +
> +/**
> + * typec_altmode_get_plug - Find cable plug alternate mode
> + * @adev: Handle to partner alternate mode
> + * @index: Cable plug index
> + *
> + * Increment reference count for cable plug alternate mode device. Returns
> + * handle to the cable plug alternate mode, or NULL if none is found.
> + */
> +struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
> +					     int index)
> +{
> +	struct altmode *port = to_altmode(adev)->partner;
> +
> +	if (port->plug[index]) {
> +		get_device(&port->plug[index]->adev.dev);
> +		return &port->plug[index]->adev;
> +	}
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
> +
> +/**
> + * typec_altmode_get_plug - Decrement cable plug alternate mode reference count

typec_altmode_put_plug

> + * @plug: Handle to the cable plug alternate mode
> + */
> +void typec_altmode_put_plug(struct typec_altmode *plug)
> +{
> +	if (plug)
> +		put_device(&plug->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_put_plug);
> +
> +int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
> +				    struct module *module)
> +{
> +	if (!drv->probe)
> +		return -EINVAL;
> +
> +	drv->driver.owner = module;
> +	drv->driver.bus = &typec_bus;
> +
> +	return driver_register(&drv->driver);
> +}
> +EXPORT_SYMBOL_GPL(__typec_altmode_register_driver);
> +
> +void typec_altmode_unregister_driver(struct typec_altmode_driver *drv)
> +{
> +	driver_unregister(&drv->driver);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_unregister_driver);
> +
> +/* -------------------------------------------------------------------------- */
> +/* API for the port drivers */
> +
> +bool typec_altmode_ufp_capable(struct typec_altmode *adev)
> +{
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	if (!is_typec_port(adev->dev.parent))
> +		return false;
> +
> +	return !(altmode->roles == TYPEC_PORT_DFP);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_ufp_capable);
> +
> +bool typec_altmode_dfp_capable(struct typec_altmode *adev)
> +{
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	if (!is_typec_port(adev->dev.parent))
> +		return false;
> +
> +	return !(altmode->roles == TYPEC_PORT_UFP);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_dfp_capable);
> +
> +/**
> + * typec_match_altmode - Match SVID to an array of alternate modes
> + * @altmodes: Array of alternate modes
> + * @n: Number of elements in the array, or -1 for NULL termiated arrays
> + * @svid: Standard or Vendor ID to match with
> + *
> + * Return pointer to an alternate mode with SVID mathing @svid, or NULL when no
> + * match is found.
> + */
> +struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
> +					  size_t n, u16 svid, u8 mode)
> +{
> +	int i;
> +
> +	for (i = 0; i < n; i++) {
> +		if (!altmodes[i])
> +			break;
> +		if (altmodes[i]->svid == svid && altmodes[i]->mode == mode)
> +			return altmodes[i];
> +	}
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(typec_match_altmode);
> +
> +/* -------------------------------------------------------------------------- */
> +
> +static ssize_t
> +description_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct typec_altmode *alt = to_typec_altmode(dev);
> +
> +	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
> +}
> +static DEVICE_ATTR_RO(description);
> +
> +static struct attribute *typec_attrs[] = {
> +	&dev_attr_description.attr,
> +	NULL
> +};
> +ATTRIBUTE_GROUPS(typec);
> +
> +static int typec_match(struct device *dev, struct device_driver *driver)
> +{
> +	struct typec_altmode_driver *drv = to_altmode_driver(driver);
> +	struct typec_altmode *altmode = to_typec_altmode(dev);
> +	const struct typec_device_id *id;
> +
> +	for (id = drv->id_table; id->svid; id++)
> +		if ((id->svid == altmode->svid) &&
> +		    (id->mode == TYPEC_ANY_MODE || id->mode == altmode->mode))
> +			return 1;
> +	return 0;
> +}
> +
> +static int typec_uevent(struct device *dev, struct kobj_uevent_env *env)
> +{
> +	struct typec_altmode *altmode = to_typec_altmode(dev);
> +
> +	if (add_uevent_var(env, "SVID=%04X", altmode->svid))
> +		return -ENOMEM;
> +
> +	if (add_uevent_var(env, "MODE=%u", altmode->mode))
> +		return -ENOMEM;
> +
> +	return add_uevent_var(env, "MODALIAS=typec:id%04Xm%02X",
> +			      altmode->svid, altmode->mode);
> +}
> +
> +static int typec_altmode_create_links(struct altmode *alt)
> +{
> +	struct device *port_dev = &alt->partner->adev.dev;
> +	struct device *dev = &alt->adev.dev;
> +	int err;
> +
> +	err = sysfs_create_link(&dev->kobj, &port_dev->kobj, "port");
> +	if (err)
> +		return err;
> +
> +	err = sysfs_create_link(&port_dev->kobj, &dev->kobj, "partner");
> +	if (err)
> +		sysfs_remove_link(&dev->kobj, "port");
> +
> +	return err;
> +}
> +
> +static int typec_probe(struct device *dev)
> +{
> +	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	/* Fail if the port does not support the alternate mode */
> +	if (!altmode->partner)
> +		return -ENODEV;
> +
> +	if (typec_altmode_create_links(altmode))
> +		dev_warn(dev, "failed to create symlinks\n");
> +
> +	return drv->probe(adev, altmode->partner->adev.vdo);
> +}
> +
> +static int typec_remove(struct device *dev)
> +{
> +	struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	if (!is_typec_port(adev->dev.parent)) {
> +		sysfs_remove_link(&altmode->partner->adev.dev.kobj, "partner");
> +		sysfs_remove_link(&adev->dev.kobj, "port");
> +	}
> +
> +	if (drv->remove)
> +		drv->remove(to_typec_altmode(dev));
> +
> +	if (adev->active)
> +		typec_altmode_exit(adev);
> +
> +	return 0;
> +}
> +
> +struct bus_type typec_bus = {
> +	.name = "typec",
> +	.dev_groups = typec_groups,
> +	.match = typec_match,
> +	.uevent = typec_uevent,
> +	.probe = typec_probe,
> +	.remove = typec_remove,
> +};
> diff --git a/drivers/usb/typec/bus.h b/drivers/usb/typec/bus.h
> new file mode 100644
> index 000000000000..38585363952f
> --- /dev/null
> +++ b/drivers/usb/typec/bus.h
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __USB_TYPEC_ALTMODE_H__
> +#define __USB_TYPEC_ALTMODE_H__
> +
> +#include <linux/usb/typec.h>
> +
> +struct bus_type;
> +
> +struct altmode {
> +	unsigned int			id;
> +	struct typec_altmode		adev;
> +
> +	enum typec_port_data		roles;
> +
> +	struct attribute		*attrs[5];
> +	char				group_name[6];
> +	struct attribute_group		group;
> +	const struct attribute_group	*groups[2];
> +
> +	struct altmode			*partner;
> +	struct altmode			*plug[2];
> +	const struct typec_altmode_ops	*ops;
> +
> +	struct blocking_notifier_head	nh;
> +};
> +
> +#define to_altmode(d) container_of(d, struct altmode, adev)
> +
> +extern struct bus_type typec_bus;
> +extern const struct device_type typec_altmode_dev_type;
> +extern const struct device_type typec_port_dev_type;
> +
> +#define is_typec_altmode(_dev_) (_dev_->type == &typec_altmode_dev_type)
> +#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
> +
> +#endif /* __USB_TYPEC_ALTMODE_H__ */
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 26eeab1491b7..33fffb853994 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -6,6 +6,7 @@
>   * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
>   */
>  
> +#include <linux/connection.h>
>  #include <linux/device.h>
>  #include <linux/module.h>
>  #include <linux/mutex.h>
> @@ -13,25 +14,12 @@
>  #include <linux/usb/typec.h>
>  #include <linux/usb/typec_mux.h>
>  
> -struct typec_altmode {
> -	struct device			dev;
> -	u16				svid;
> -	u8				mode;
> -
> -	u32				vdo;
> -	char				*desc;
> -	enum typec_port_type		roles;
> -	unsigned int			active:1;
> -
> -	struct attribute		*attrs[5];
> -	char				group_name[6];
> -	struct attribute_group		group;
> -	const struct attribute_group	*groups[2];
> -};
> +#include "bus.h"
>  
>  struct typec_plug {
>  	struct device			dev;
>  	enum typec_plug_index		index;
> +	struct ida			mode_ids;
>  };
>  
>  struct typec_cable {
> @@ -46,11 +34,13 @@ struct typec_partner {
>  	unsigned int			usb_pd:1;
>  	struct usb_pd_identity		*identity;
>  	enum typec_accessory		accessory;
> +	struct ida			mode_ids;
>  };
>  
>  struct typec_port {
>  	unsigned int			id;
>  	struct device			dev;
> +	struct ida			mode_ids;
>  
>  	int				prefer_role;
>  	enum typec_data_role		data_role;
> @@ -71,17 +61,14 @@ struct typec_port {
>  #define to_typec_plug(_dev_) container_of(_dev_, struct typec_plug, dev)
>  #define to_typec_cable(_dev_) container_of(_dev_, struct typec_cable, dev)
>  #define to_typec_partner(_dev_) container_of(_dev_, struct typec_partner, dev)
> -#define to_altmode(_dev_) container_of(_dev_, struct typec_altmode, dev)
>  
>  static const struct device_type typec_partner_dev_type;
>  static const struct device_type typec_cable_dev_type;
>  static const struct device_type typec_plug_dev_type;
> -static const struct device_type typec_port_dev_type;
>  
>  #define is_typec_partner(_dev_) (_dev_->type == &typec_partner_dev_type)
>  #define is_typec_cable(_dev_) (_dev_->type == &typec_cable_dev_type)
>  #define is_typec_plug(_dev_) (_dev_->type == &typec_plug_dev_type)
> -#define is_typec_port(_dev_) (_dev_->type == &typec_port_dev_type)
>  
>  static DEFINE_IDA(typec_index_ida);
>  static struct class *typec_class;
> @@ -163,27 +150,141 @@ static void typec_report_identity(struct device *dev)
>  /* ------------------------------------------------------------------------- */
>  /* Alternate Modes */
>  
> +static int altmode_match(struct device *dev, void *data)
> +{
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct typec_device_id *id = data;
> +
> +	if (!is_typec_altmode(dev))
> +		return 0;
> +
> +	return ((adev->svid == id->svid) && (adev->mode == id->mode));
> +}
> +
> +static void typec_altmode_get_partner(struct altmode *altmode)
> +{
> +	struct typec_altmode *adev = &altmode->adev;
> +	struct typec_device_id id = { adev->svid, adev->mode, };
> +	struct typec_port *port = typec_altmode2port(adev);
> +	struct altmode *partner;
> +	struct device *dev;
> +
> +	dev = device_find_child(&port->dev, &id, altmode_match);
> +	if (!dev)
> +		return;
> +
> +	/* Bind the port alt mode to the partner/plug alt mode. */
> +	partner = to_altmode(to_typec_altmode(dev));
> +	altmode->partner = partner;
> +
> +	/* Bind the partner/plug alt mode to the port alt mode. */
> +	if (is_typec_plug(adev->dev.parent)) {
> +		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
> +
> +		partner->plug[plug->index] = altmode;
> +	} else {
> +		partner->partner = altmode;
> +	}
> +}
> +
> +static void typec_altmode_put_partner(struct altmode *altmode)
> +{
> +	struct altmode *partner = altmode->partner;
> +	struct typec_altmode *adev;
> +
> +	if (!partner)
> +		return;
> +
> +	adev = &partner->adev;
> +
> +	if (is_typec_plug(adev->dev.parent)) {
> +		struct typec_plug *plug = to_typec_plug(adev->dev.parent);
> +
> +		partner->plug[plug->index] = NULL;
> +	} else {
> +		partner->partner = NULL;
> +	}
> +	put_device(&adev->dev);
> +}
> +
> +static int __typec_port_match(struct device *dev, const void *name)
> +{
> +	return !strcmp((const char *)name, dev_name(dev));
> +}
> +
> +static void *typec_port_match(struct devcon *con, int ep, void *data)
> +{
> +	return class_find_device(typec_class, NULL, con->endpoint[ep],
> +				 __typec_port_match);
> +}
> +
> +struct typec_altmode *
> +typec_altmode_register_notifier(struct device *dev, u16 svid, u8 mode,
> +				struct notifier_block *nb)
> +{
> +	struct typec_device_id id = { svid, mode, };
> +	struct device *altmode_dev;
> +	struct device *port_dev;
> +	struct altmode *altmode;
> +	int ret;
> +
> +	/* Find the port linked to the caller */
> +	port_dev = __device_find_connection(dev, NULL, NULL, typec_port_match);
> +	if (!port_dev)
> +		return ERR_PTR(-ENODEV);
> +
> +	/* Find the altmode with matching svid */
> +	altmode_dev = device_find_child(port_dev, &id, altmode_match);
> +
> +	put_device(port_dev);
> +
> +	if (!altmode_dev)
> +		return ERR_PTR(-ENODEV);
> +
> +	altmode = to_altmode(to_typec_altmode(altmode_dev));
> +
> +	/* Register notifier */
> +	ret = blocking_notifier_chain_register(&altmode->nh, nb);
> +	if (ret) {
> +		put_device(altmode_dev);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return &altmode->adev;
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_register_notifier);
> +
> +void typec_altmode_unregister_notifier(struct typec_altmode *adev,
> +				       struct notifier_block *nb)
> +{
> +	struct altmode *altmode = to_altmode(adev);
> +
> +	blocking_notifier_chain_unregister(&altmode->nh, nb);
> +	put_device(&adev->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_altmode_unregister_notifier);
> +
>  /**
>   * typec_altmode_update_active - Report Enter/Exit mode
> - * @alt: Handle to the alternate mode
> + * @adev: Handle to the alternate mode
>   * @mode: Mode index
>   * @active: True when the mode has been entered
>   *
>   * If a partner or cable plug executes Enter/Exit Mode command successfully, the
>   * drivers use this routine to report the updated state of the mode.
>   */
> -void typec_altmode_update_active(struct typec_altmode *alt, int mode,
> +void typec_altmode_update_active(struct typec_altmode *adev, int mode,
>  				 bool active)
>  {
>  	char dir[6];
>  
> -	if (alt->active == active)
> +	if (adev->active == active)
>  		return;
>  
> -	alt->active = active;
> +	adev->active = active;
>  	snprintf(dir, sizeof(dir), "mode%d", mode);
> -	sysfs_notify(&alt->dev.kobj, dir, "active");
> -	kobject_uevent(&alt->dev.kobj, KOBJ_CHANGE);
> +	sysfs_notify(&adev->dev.kobj, dir, "active");
> +	kobject_uevent(&adev->dev.kobj, KOBJ_CHANGE);
>  }
>  EXPORT_SYMBOL_GPL(typec_altmode_update_active);
>  
> @@ -210,7 +311,7 @@ EXPORT_SYMBOL_GPL(typec_altmode2port);
>  static ssize_t
>  vdo_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *alt = to_typec_altmode(dev);
>  
>  	return sprintf(buf, "0x%08x\n", alt->vdo);
>  }
> @@ -219,7 +320,7 @@ static DEVICE_ATTR_RO(vdo);
>  static ssize_t
>  description_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *alt = to_typec_altmode(dev);
>  
>  	return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
>  }
> @@ -228,28 +329,46 @@ static DEVICE_ATTR_RO(description);
>  static ssize_t
>  active_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *alt = to_typec_altmode(dev);
>  
>  	return sprintf(buf, "%s\n", alt->active ? "yes" : "no");
>  }
>  
> -static ssize_t
> -active_store(struct device *dev, struct device_attribute *attr,
> -			   const char *buf, size_t size)
> +static ssize_t active_store(struct device *dev, struct device_attribute *attr,
> +			    const char *buf, size_t size)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> -	struct typec_port *port = typec_altmode2port(alt);
> -	bool activate;
> +	struct typec_altmode *adev = to_typec_altmode(dev);
> +	struct typec_port *port = typec_altmode2port(adev);
> +	struct altmode *altmode = to_altmode(adev);
> +	bool enter;
>  	int ret;
>  
>  	if (!port->cap->activate_mode)
>  		return -EOPNOTSUPP;
>  
> -	ret = kstrtobool(buf, &activate);
> +	ret = kstrtobool(buf, &enter);
>  	if (ret)
>  		return ret;
>  
> -	ret = port->cap->activate_mode(port->cap, alt->mode, activate);
> +	if (adev->active == enter)
> +		return size;
> +
> +	if (is_typec_port(adev->dev.parent)) {
> +		typec_altmode_update_active(adev, adev->mode, enter);
> +		sysfs_notify(&adev->dev.kobj, NULL, "active");
> +
> +		if (!altmode->partner)
> +			return size;
> +	} else {
> +		adev = &altmode->partner->adev;
> +
> +		if (!adev->active) {
> +			dev_warn(dev, "port has the mode disabled\n");
> +			return -EPERM;
> +		}
> +	}
> +
> +	ret = port->cap->activate_mode(adev, enter);
>  	if (ret)
>  		return ret;
>  
> @@ -261,7 +380,7 @@ static ssize_t
>  supported_roles_show(struct device *dev, struct device_attribute *attr,
>  		     char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct altmode *alt = to_altmode(to_typec_altmode(dev));
>  	ssize_t ret;
>  
>  	switch (alt->roles) {
> @@ -280,29 +399,72 @@ supported_roles_show(struct device *dev, struct device_attribute *attr,
>  }
>  static DEVICE_ATTR_RO(supported_roles);
>  
> -static void typec_altmode_release(struct device *dev)
> +static ssize_t
> +mode_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
>  
> -	kfree(alt);
> +	return sprintf(buf, "%u\n", adev->mode);
>  }
> +static DEVICE_ATTR_RO(mode);
>  
> -static ssize_t svid_show(struct device *dev, struct device_attribute *attr,
> -			 char *buf)
> +static ssize_t
> +svid_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
> -	struct typec_altmode *alt = to_altmode(dev);
> +	struct typec_altmode *adev = to_typec_altmode(dev);
>  
> -	return sprintf(buf, "%04x\n", alt->svid);
> +	return sprintf(buf, "%04x\n", adev->svid);
>  }
>  static DEVICE_ATTR_RO(svid);
>  
>  static struct attribute *typec_altmode_attrs[] = {
> +	&dev_attr_active.attr,
> +	&dev_attr_mode.attr,
>  	&dev_attr_svid.attr,
> +	&dev_attr_vdo.attr,
>  	NULL
>  };
>  ATTRIBUTE_GROUPS(typec_altmode);
>  
> -static const struct device_type typec_altmode_dev_type = {
> +static int altmode_id_get(struct device *dev)
> +{
> +	struct ida *ids;
> +
> +	if (is_typec_partner(dev))
> +		ids = &to_typec_partner(dev)->mode_ids;
> +	else if (is_typec_plug(dev))
> +		ids = &to_typec_plug(dev)->mode_ids;
> +	else
> +		ids = &to_typec_port(dev)->mode_ids;
> +
> +	return ida_simple_get(ids, 0, 0, GFP_KERNEL);
> +}
> +
> +static void altmode_id_remove(struct device *dev, int id)
> +{
> +	struct ida *ids;
> +
> +	if (is_typec_partner(dev))
> +		ids = &to_typec_partner(dev)->mode_ids;
> +	else if (is_typec_plug(dev))
> +		ids = &to_typec_plug(dev)->mode_ids;
> +	else
> +		ids = &to_typec_port(dev)->mode_ids;
> +
> +	ida_simple_remove(ids, id);
> +}
> +
> +static void typec_altmode_release(struct device *dev)
> +{
> +	struct altmode *alt = to_altmode(to_typec_altmode(dev));
> +
> +	typec_altmode_put_partner(alt);
> +
> +	altmode_id_remove(alt->adev.dev.parent, alt->id);
> +	kfree(alt);
> +}
> +
> +const struct device_type typec_altmode_dev_type = {
>  	.name = "typec_alternate_mode",
>  	.groups = typec_altmode_groups,
>  	.release = typec_altmode_release,
> @@ -312,58 +474,72 @@ static struct typec_altmode *
>  typec_register_altmode(struct device *parent,
>  		       const struct typec_altmode_desc *desc)
>  {
> -	struct typec_altmode *alt;
> +	unsigned int id = altmode_id_get(parent);
> +	bool is_port = is_typec_port(parent);
> +	struct altmode *alt;
>  	int ret;
>  
>  	alt = kzalloc(sizeof(*alt), GFP_KERNEL);
>  	if (!alt)
>  		return ERR_PTR(-ENOMEM);
>  
> -	alt->svid = desc->svid;
> -	alt->mode = desc->mode;
> -	alt->vdo = desc->vdo;
> +	alt->adev.svid = desc->svid;
> +	alt->adev.mode = desc->mode;
> +	alt->adev.vdo = desc->vdo;
>  	alt->roles = desc->roles;
> +	alt->id = id;
>  
>  	alt->attrs[0] = &dev_attr_vdo.attr;
>  	alt->attrs[1] = &dev_attr_description.attr;
>  	alt->attrs[2] = &dev_attr_active.attr;
>  
> -	if (is_typec_port(parent))
> +	if (is_port) {
>  		alt->attrs[3] = &dev_attr_supported_roles.attr;
> +		alt->adev.active = true; /* Enabled by default */
> +	}
>  
>  	sprintf(alt->group_name, "mode%d", desc->mode);
>  	alt->group.name = alt->group_name;
>  	alt->group.attrs = alt->attrs;
>  	alt->groups[0] = &alt->group;
>  
> -	alt->dev.parent = parent;
> -	alt->dev.groups = alt->groups;
> -	alt->dev.type = &typec_altmode_dev_type;
> -	dev_set_name(&alt->dev, "%s-%04x:%u", dev_name(parent),
> -		     alt->svid, alt->mode);
> +	alt->adev.dev.parent = parent;
> +	alt->adev.dev.groups = alt->groups;
> +	alt->adev.dev.type = &typec_altmode_dev_type;
> +	dev_set_name(&alt->adev.dev, "%s.%u", dev_name(parent), id);
> +
> +	/* Link partners and plugs with the ports */
> +	if (is_port)
> +		BLOCKING_INIT_NOTIFIER_HEAD(&alt->nh);
> +	else
> +		typec_altmode_get_partner(alt);
>  
> -	ret = device_register(&alt->dev);
> +	/* The partners are bind to drivers */
> +	if (is_typec_partner(parent))
> +		alt->adev.dev.bus = &typec_bus;
> +
> +	ret = device_register(&alt->adev.dev);
>  	if (ret) {
>  		dev_err(parent, "failed to register alternate mode (%d)\n",
>  			ret);
> -		put_device(&alt->dev);
> +		put_device(&alt->adev.dev);
>  		return ERR_PTR(ret);
>  	}
>  
> -	return alt;
> +	return &alt->adev;
>  }
>  
>  /**
>   * typec_unregister_altmode - Unregister Alternate Mode
> - * @alt: The alternate mode to be unregistered
> + * @adev: The alternate mode to be unregistered
>   *
>   * Unregister device created with typec_partner_register_altmode(),
>   * typec_plug_register_altmode() or typec_port_register_altmode().
>   */
> -void typec_unregister_altmode(struct typec_altmode *alt)
> +void typec_unregister_altmode(struct typec_altmode *adev)
>  {
> -	if (!IS_ERR_OR_NULL(alt))
> -		device_unregister(&alt->dev);
> +	if (!IS_ERR_OR_NULL(adev))
> +		device_unregister(&adev->dev);
>  }
>  EXPORT_SYMBOL_GPL(typec_unregister_altmode);
>  
> @@ -401,6 +577,7 @@ static void typec_partner_release(struct device *dev)
>  {
>  	struct typec_partner *partner = to_typec_partner(dev);
>  
> +	ida_destroy(&partner->mode_ids);
>  	kfree(partner);
>  }
>  
> @@ -466,6 +643,7 @@ struct typec_partner *typec_register_partner(struct typec_port *port,
>  	if (!partner)
>  		return ERR_PTR(-ENOMEM);
>  
> +	ida_init(&partner->mode_ids);
>  	partner->usb_pd = desc->usb_pd;
>  	partner->accessory = desc->accessory;
>  
> @@ -514,6 +692,7 @@ static void typec_plug_release(struct device *dev)
>  {
>  	struct typec_plug *plug = to_typec_plug(dev);
>  
> +	ida_destroy(&plug->mode_ids);
>  	kfree(plug);
>  }
>  
> @@ -566,6 +745,7 @@ struct typec_plug *typec_register_plug(struct typec_cable *cable,
>  
>  	sprintf(name, "plug%d", desc->index);
>  
> +	ida_init(&plug->mode_ids);
>  	plug->index = desc->index;
>  	plug->dev.class = typec_class;
>  	plug->dev.parent = &cable->dev;
> @@ -1080,12 +1260,13 @@ static void typec_release(struct device *dev)
>  	struct typec_port *port = to_typec_port(dev);
>  
>  	ida_simple_remove(&typec_index_ida, port->id);
> +	ida_destroy(&port->mode_ids);
>  	typec_switch_put(port->sw);
>  	typec_mux_put(port->mux);
>  	kfree(port);
>  }
>  
> -static const struct device_type typec_port_dev_type = {
> +const struct device_type typec_port_dev_type = {
>  	.name = "typec_port",
>  	.groups = typec_groups,
>  	.uevent = typec_uevent,
> @@ -1238,6 +1419,8 @@ EXPORT_SYMBOL_GPL(typec_set_mode);
>   * typec_port_register_altmode - Register USB Type-C Port Alternate Mode
>   * @port: USB Type-C Port that supports the alternate mode
>   * @desc: Description of the alternate mode
> + * @ops: Port specific operations for the alternate mode
> + * @drvdata: Private pointer to driver specific info
>   *
>   * This routine is used to register an alternate mode that @port is capable of
>   * supporting.
> @@ -1322,10 +1505,12 @@ struct typec_port *typec_register_port(struct device *parent,
>  		break;
>  	}
>  
> +	ida_init(&port->mode_ids);
> +	mutex_init(&port->port_type_lock);
> +
>  	port->id = id;
>  	port->cap = cap;
>  	port->port_type = cap->type;
> -	mutex_init(&port->port_type_lock);
>  	port->prefer_role = cap->prefer_role;
>  
>  	port->dev.class = typec_class;
> @@ -1369,8 +1554,19 @@ EXPORT_SYMBOL_GPL(typec_unregister_port);
>  
>  static int __init typec_init(void)
>  {
> +	int ret;
> +
> +	ret = bus_register(&typec_bus);
> +	if (ret)
> +		return ret;
> +
>  	typec_class = class_create(THIS_MODULE, "typec");
> -	return PTR_ERR_OR_ZERO(typec_class);
> +	if (IS_ERR(typec_class)) {
> +		bus_unregister(&typec_bus);
> +		return PTR_ERR(typec_class);
> +	}
> +
> +	return 0;
>  }
>  subsys_initcall(typec_init);
>  
> @@ -1378,6 +1574,7 @@ static void __exit typec_exit(void)
>  {
>  	class_destroy(typec_class);
>  	ida_destroy(&typec_index_ida);
> +	bus_unregister(&typec_bus);
>  }
>  module_exit(typec_exit);
>  
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index 48fb2b43c35a..17c1a912f524 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -733,4 +733,19 @@ struct tb_service_id {
>  #define TBSVC_MATCH_PROTOCOL_VERSION	0x0004
>  #define TBSVC_MATCH_PROTOCOL_REVISION	0x0008
>  
> +/* USB Type-C Alternate Modes */
> +
> +#define TYPEC_ANY_MODE	0x7
> +
> +/**
> + * struct typec_device_id - USB Type-C alternate mode identifiers
> + * @svid: Standard or Vendor ID
> + * @mode: Mode index
> + */
> +struct typec_device_id {
> +	__u16 svid;
> +	__u8 mode;
> +	kernel_ulong_t driver_data;
> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
> index 278b6b42c7ea..a19aa3db4272 100644
> --- a/include/linux/usb/typec.h
> +++ b/include/linux/usb/typec.h
> @@ -4,16 +4,13 @@
>  #define __LINUX_USB_TYPEC_H
>  
>  #include <linux/types.h>
> -
> -/* XXX: Once we have a header for USB Power Delivery, this belongs there */
> -#define ALTMODE_MAX_MODES	6
> +#include <linux/usb/typec_altmode.h>
>  
>  /* USB Type-C Specification releases */
>  #define USB_TYPEC_REV_1_0	0x100 /* 1.0 */
>  #define USB_TYPEC_REV_1_1	0x110 /* 1.1 */
>  #define USB_TYPEC_REV_1_2	0x120 /* 1.2 */
>  
> -struct typec_altmode;
>  struct typec_partner;
>  struct typec_cable;
>  struct typec_plug;
> @@ -107,7 +104,7 @@ struct typec_altmode_desc {
>  	u8			mode;
>  	u32			vdo;
>  	/* Only used with ports */
> -	enum typec_port_type	roles;
> +	enum typec_port_data	roles;
>  };
>  
>  struct typec_altmode
> @@ -118,7 +115,8 @@ struct typec_altmode
>  			     const struct typec_altmode_desc *desc);
>  struct typec_altmode
>  *typec_port_register_altmode(struct typec_port *port,
> -			     const struct typec_altmode_desc *desc);
> +			    const struct typec_altmode_desc *desc);
> +
>  void typec_unregister_altmode(struct typec_altmode *altmode);
>  
>  struct typec_port *typec_altmode2port(struct typec_altmode *alt);
> @@ -213,12 +211,10 @@ struct typec_capability {
>  				  enum typec_role);
>  	int		(*vconn_set)(const struct typec_capability *,
>  				     enum typec_role);
> -
> -	int		(*activate_mode)(const struct typec_capability *,
> -					 int mode, int activate);
>  	int		(*port_type_set)(const struct typec_capability *,
> -					enum typec_port_type);
> +					 enum typec_port_type);
>  
> +	int		(*activate_mode)(struct typec_altmode *alt, int active);
>  };
>  
>  /* Specific to try_role(). Indicates the user want's to clear the preference. */
> diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
> new file mode 100644
> index 000000000000..bc765352a3c8
> --- /dev/null
> +++ b/include/linux/usb/typec_altmode.h
> @@ -0,0 +1,136 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __USB_TYPEC_ALTMODE_H
> +#define __USB_TYPEC_ALTMODE_H
> +
> +#include <linux/device.h>
> +#include <linux/mod_devicetable.h>
> +
> +#define MODE_DISCOVERY_MAX	6
> +
> +/**
> + * struct typec_altmode - USB Type-C alternate mode device
> + * @dev: Driver model's view of this device
> + * @svid: Standard or Vendor ID (SVID) of the alternate mode
> + * @mode: Index of the Mode
> + * @vdo: VDO returned by Discover Modes USB PD command
> + * @desc: Optional human readable description of the mode
> + * @active: Tells has the mode been entered or not
> + */
> +struct typec_altmode {
> +	struct device		dev;
> +	u16			svid;
> +	int			mode;
> +	u32			vdo;
> +	char			*desc;
> +	bool			active;
> +} __packed;
> +
> +#define to_typec_altmode(d) container_of(d, struct typec_altmode, dev)
> +
> +static inline void typec_altmode_set_drvdata(struct typec_altmode *altmode,
> +					     void *data)
> +{
> +	dev_set_drvdata(&altmode->dev, data);
> +}
> +
> +static inline void *typec_altmode_get_drvdata(struct typec_altmode *altmode)
> +{
> +	return dev_get_drvdata(&altmode->dev);
> +}
> +
> +/**
> + * struct typec_altmode_ops - Alternate mode specific operations vector
> + * @enter: Operations to be executed with Enter Mode Command
> + * @exit: Operations to be executed with Exit Mode Command
> + * @attention: Callback for Attention Command
> + * @vdm: Callback for SVID specific commands
> + * @notify: Communication channel for platform and the alternate mode
> + */
> +struct typec_altmode_ops {
> +	void (*enter)(struct typec_altmode *altmode);
> +	void (*exit)(struct typec_altmode *altmode);
> +	void (*attention)(struct typec_altmode *altmode, const u32 vdo);
> +	int (*vdm)(struct typec_altmode *altmode, const u32 hdr,
> +		   const u32 *vdo, int cnt);
> +	int (*notify)(struct typec_altmode *altmode, unsigned long conf,
> +		      void *data);
> +};
> +
> +void typec_altmode_register_ops(struct typec_altmode *altmode,
> +				const struct typec_altmode_ops *ops);
> +
> +int typec_altmode_enter(struct typec_altmode *altmode);
> +int typec_altmode_exit(struct typec_altmode *altmode);
> +void typec_altmode_attention(struct typec_altmode *altmode, const u32 vdo);
> +int typec_altmode_vdm(struct typec_altmode *altmode,
> +		      const u32 header, const u32 *vdo, int count);
> +int typec_altmode_notify(struct typec_altmode *altmode, unsigned long conf,
> +			 void *data);
> +
> +/* Return values for type_altmode_vdm() */
> +#define VDM_DONE		0 /* Don't care */
> +#define VDM_OK			1 /* Suits me */
> +
> +/*
> + * These are the pin states (USB, Safe and Alt Mode) and accessory modes (Audio
> + * and Debug) defined in USB Type-C Specification. SVID specific pin states are
> + * expected to follow and start from the value TYPEC_STATE_MODAL.
> + *
> + * Port drivers should use TYPEC_STATE_AUDIO and TYPEC_STATE_DEBUG as the
> + * operation value for typec_set_mode() when accessory modes are in use.
> + *
> + * NOTE: typec_altmode_notify() does not accept values smaller then
> + * TYPEC_STATE_MODAL. USB Type-C bus will follow USB Type-C Specification with
> + * TYPEC_STATE_USB and TYPEC_STATE_SAFE.
> + */
> +enum {
> +	TYPEC_STATE_USB,	/* USB Operation */
> +	TYPEC_STATE_AUDIO,	/* Audio Accessory */
> +	TYPEC_STATE_DEBUG,	/* Debug Accessory */
> +	TYPEC_STATE_SAFE,	/* USB Safe State */
> +	TYPEC_STATE_MODAL,	/* Alternate Modes */
> +};
> +
> +#define TYPEC_MODAL_STATE(_state_)	((_state_) + TYPEC_STATE_MODAL)
> +
> +struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *altmode,
> +					     int index);
> +void typec_altmode_put_plug(struct typec_altmode *plug);
> +
> +bool typec_altmode_ufp_capable(struct typec_altmode *altmode);
> +bool typec_altmode_dfp_capable(struct typec_altmode *altmode);
> +struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
> +					  size_t n, u16 svid, u8 mode);
> +
> +/**
> + * struct typec_altmode_driver - USB Type-C alternate mode device driver
> + * @id_table: Null terminated array of SVIDs
> + * @probe: Callback for device binding
> + * @remove: Callback for device unbinding
> + * @driver: Device driver model driver
> + *
> + * These drivers will be bind to the partner alternate mode devices. They will
> + * handle all SVID specific communication.
> + */
> +struct typec_altmode_driver {
> +	const struct typec_device_id *id_table;
> +	int (*probe)(struct typec_altmode *altmode, u32 port_vdo);
> +	void (*remove)(struct typec_altmode *altmode);
> +	struct device_driver driver;
> +};
> +
> +#define to_altmode_driver(d) container_of(d, struct typec_altmode_driver, \
> +					  driver)
> +
> +#define typec_altmode_register_driver(drv) \
> +		__typec_altmode_register_driver(drv, THIS_MODULE)
> +int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
> +				    struct module *module);
> +void typec_altmode_unregister_driver(struct typec_altmode_driver *drv);
> +
> +#define module_typec_altmode_driver(__typec_altmode_driver) \
> +	module_driver(__typec_altmode_driver, typec_altmode_register_driver, \
> +		      typec_altmode_unregister_driver)
> +
> +#endif /* __USB_TYPEC_ALTMODE_H */
> diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
> index 9fad6afe4c41..c48c7f56ae64 100644
> --- a/scripts/mod/devicetable-offsets.c
> +++ b/scripts/mod/devicetable-offsets.c
> @@ -218,5 +218,9 @@ int main(void)
>  	DEVID_FIELD(tb_service_id, protocol_version);
>  	DEVID_FIELD(tb_service_id, protocol_revision);
>  
> +	DEVID(typec_device_id);
> +	DEVID_FIELD(typec_device_id, svid);
> +	DEVID_FIELD(typec_device_id, mode);
> +
>  	return 0;
>  }
> diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
> index b9beeaa4695b..a8afba836409 100644
> --- a/scripts/mod/file2alias.c
> +++ b/scripts/mod/file2alias.c
> @@ -1341,6 +1341,19 @@ static int do_tbsvc_entry(const char *filename, void *symval, char *alias)
>  }
>  ADD_TO_DEVTABLE("tbsvc", tb_service_id, do_tbsvc_entry);
>  
> +/* Looks like: typec:idNmN */
> +static int do_typec_entry(const char *filename, void *symval, char *alias)
> +{
> +	DEF_FIELD(symval, typec_device_id, svid);
> +	DEF_FIELD(symval, typec_device_id, mode);
> +
> +	sprintf(alias, "typec:id%04X", svid);
> +	ADD(alias, "m", mode != TYPEC_ANY_MODE, mode);
> +
> +	return 1;
> +}
> +ADD_TO_DEVTABLE("typec", typec_device_id, do_typec_entry);
> +
>  /* Does namelen bytes of name exactly match the symbol? */
>  static bool sym_is(const char *name, unsigned namelen, const char *symbol)
>  {
> -- 
> 2.16.1
>
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Re: [RFC PATCH v2 2/3] usb: typec: Bus type for alternate modes

[Heikki Krogerus]

Hi Guenter,

On Fri, Mar 16, 2018 at 02:33:36PM -0700, Guenter Roeck wrote:
> On Fri, Mar 09, 2018 at 06:19:17PM +0300, Heikki Krogerus wrote:
> > diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
> > new file mode 100644
> > index 000000000000..92944aaf3d6a
> > --- /dev/null
> > +++ b/drivers/usb/typec/bus.c
> > @@ -0,0 +1,421 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/**
> > + * Bus for USB Type-C Alternate Modes
> > + *
> > + * Copyright (C) 2018 Intel Corporation
> > + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > + */
> > +
> > +#include "bus.h"
> > +
> > +/* -------------------------------------------------------------------------- */
> > +/* Common API */
> > +
> > +/**
> > + * typec_altmode_notify - Communication between the OS and alternate mode driver
> > + * @adev: Handle to the alternate mode
> > + * @conf: Alternate mode specific configuration value
> > + * @data: Alternate mode specific data
> > + *
> > + * The primary purpose for this function is to allow the alternate mode drivers
> > + * to tell which pin configuration has been negotiated with the partner. That
> > + * information will then be used for example to configure the muxes.
> > + * Communication to the other direction is also possible, and low level device
> > + * drivers can also send notifications to the alternate mode drivers. The actual
> > + * communication will be specific for every SVID.
> > + */
> > +int typec_altmode_notify(struct typec_altmode *adev,
> > +			 unsigned long conf, void *data)
> > +{
> > +	struct altmode *altmode;
> > +	struct altmode *partner;
> > +	int ret;
> > +
> > +	/*
> > +	 * All SVID specific configuration values must start from
> > +	 * TYPEC_STATE_MODAL. The first values are reserved for the pin states
> > +	 * defined in USB Type-C specification: TYPEC_STATE_USB and
> > +	 * TYPEC_STATE_SAFE. We'll follow this rule even with modes that do not
> > +	 * require pin reconfiguration for the sake of simplicity.
> > +	 */
> > +	if (conf < TYPEC_STATE_MODAL)
> > +		return -EINVAL;
> > +
> > +	if (!adev)
> > +		return 0;
> > +
> > +	altmode = to_altmode(adev);
> > +
> > +	if (!altmode->partner)
> > +		return -ENODEV;
> > +
> > +	ret = typec_set_mode(typec_altmode2port(adev), (int)conf);
> > +	if (ret)
> > +		return ret;
> > +
> > +	partner = altmode->partner;
> > +
> > +	blocking_notifier_call_chain(is_typec_port(adev->dev.parent) ?
> > +				     &altmode->nh : &partner->nh,
> > +				     conf, data);
> > +
> > +	if (partner->ops && partner->ops->notify)
> > +		return partner->ops->notify(&partner->adev, conf, data);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_notify);
> > +
> > +/**
> > + * typec_altmode_enter - Enter Mode
> > + * @adev: The alternate mode
> > + *
> > + * The alternate mode drivers use this function to enter mode. The port drivers
> > + * use this to inform the alternate mode drivers that their mode has been
> > + * entered successfully.
> > + */
> > +int typec_altmode_enter(struct typec_altmode *adev)
> > +{
> > +	struct altmode *partner = to_altmode(adev)->partner;
> > +	struct typec_altmode *pdev = &partner->adev;
> > +	int ret;
> > +
> > +	if (is_typec_port(adev->dev.parent)) {
> > +		typec_altmode_update_active(pdev, pdev->mode, true);
> > +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> > +		goto enter_mode;
> > +	}
> > +
> > +	if (!pdev->active)
> > +		return -EPERM;
> > +
> > +	/* First moving to USB Safe State */
> > +	ret = typec_set_mode(typec_altmode2port(adev), TYPEC_STATE_SAFE);
> > +	if (ret)
> > +		return ret;
> > +
> > +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> > +
> > +enter_mode:
> > +	/* Enter Mode command */
> > +	if (partner->ops && partner->ops->enter)
> > +		partner->ops->enter(pdev);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_enter);
> > +
> > +/**
> > + * typec_altmode_enter - Exit Mode
> 
> typec_altmode_exit

Yes.

> > + * @adev: The alternate mode
> > + *
> > + * The alternate mode drivers use this function to exit mode. The port drivers
> > + * can also inform the alternate mode drivers with this function that the mode
> > + * was successfully exited.
> > + */
> > +int typec_altmode_exit(struct typec_altmode *adev)
> > +{
> > +	struct altmode *partner = to_altmode(adev)->partner;
> > +	struct typec_port *port = typec_altmode2port(adev);
> > +	struct typec_altmode *pdev = &partner->adev;
> > +	int ret;
> > +
> > +	/* In case of port, just calling the driver and exiting */
> > +	if (is_typec_port(adev->dev.parent)) {
> > +		typec_altmode_update_active(pdev, pdev->mode, false);
> > +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> > +
> > +		if (partner->ops && partner->ops->exit)
> > +			partner->ops->exit(pdev);
> > +		return 0;
> > +	}
> > +
> > +	/* Moving to USB Safe State */
> > +	ret = typec_set_mode(port, TYPEC_STATE_SAFE);
> > +	if (ret)
> > +		return ret;
> > +
> > +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> > +
> > +	/* Exit Mode command */
> > +	if (partner->ops && partner->ops->exit)
> > +		partner->ops->exit(pdev);
> > +
> > +	/* Back to USB operation */
> > +	ret = typec_set_mode(port, TYPEC_STATE_USB);
> > +	if (ret)
> > +		return ret;
> > +
> > +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_USB, NULL);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_exit);
> > +
> > +/**
> > + * typec_altmode_attention - Attention command
> > + * @adev: The alternate mode
> > + * @vdo: VDO for the Attention command
> > + *
> > + * Notifies the partner of @adev about Attention command.
> > + */
> > +void typec_altmode_attention(struct typec_altmode *adev, const u32 vdo)
> > +{
> > +	struct altmode *partner = to_altmode(adev)->partner;
> > +
> > +	if (partner && partner->ops && partner->ops->attention)
> > +		partner->ops->attention(&partner->adev, vdo);
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_attention);
> > +
> > +/**
> > + * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
> > + * @adev: Alternate mode handle
> > + * @header: VDM Header
> > + * @vdo: Array of Vendor Defined Data Objects
> > + * @count: Number of Data Objects
> > + *
> > + * The alternate mode drivers use this function for SVID specific communication
> > + * with the partner. The port drivers use it to deliver the Structured VDMs
> > + * received from the partners to the alternate mode drivers.
> > + */
> > +int typec_altmode_vdm(struct typec_altmode *adev,
> > +		      const u32 header, const u32 *vdo, int count)
> > +{
> > +	struct altmode *altmode;
> > +	struct altmode *partner;
> > +
> > +	if (!adev)
> > +		return 0;
> > +
> > +	altmode = to_altmode(adev);
> > +
> > +	if (!altmode->partner)
> > +		return -ENODEV;
> > +
> > +	partner = altmode->partner;
> > +
> > +	if (partner->ops && partner->ops->vdm)
> > +		return partner->ops->vdm(&partner->adev, header, vdo, count);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_vdm);
> > +
> > +void typec_altmode_register_ops(struct typec_altmode *adev,
> > +				const struct typec_altmode_ops *ops)
> > +{
> > +	to_altmode(adev)->ops = ops;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_register_ops);
> > +
> > +/* -------------------------------------------------------------------------- */
> > +/* API for the alternate mode drivers */
> > +
> > +/**
> > + * typec_altmode_get_plug - Find cable plug alternate mode
> > + * @adev: Handle to partner alternate mode
> > + * @index: Cable plug index
> > + *
> > + * Increment reference count for cable plug alternate mode device. Returns
> > + * handle to the cable plug alternate mode, or NULL if none is found.
> > + */
> > +struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
> > +					     int index)
> > +{
> > +	struct altmode *port = to_altmode(adev)->partner;
> > +
> > +	if (port->plug[index]) {
> > +		get_device(&port->plug[index]->adev.dev);
> > +		return &port->plug[index]->adev;
> > +	}
> > +
> > +	return NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
> > +
> > +/**
> > + * typec_altmode_get_plug - Decrement cable plug alternate mode reference count
> 
> typec_altmode_put_plug

Yes.


Thanks,

-- 
heikki

[RFC,v2,2/3] usb: typec: Bus type for alternate modes

[Heikki Krogerus]

Hi Guenter,

On Fri, Mar 16, 2018 at 02:33:36PM -0700, Guenter Roeck wrote:
> On Fri, Mar 09, 2018 at 06:19:17PM +0300, Heikki Krogerus wrote:
> > diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
> > new file mode 100644
> > index 000000000000..92944aaf3d6a
> > --- /dev/null
> > +++ b/drivers/usb/typec/bus.c
> > @@ -0,0 +1,421 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/**
> > + * Bus for USB Type-C Alternate Modes
> > + *
> > + * Copyright (C) 2018 Intel Corporation
> > + * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > + */
> > +
> > +#include "bus.h"
> > +
> > +/* -------------------------------------------------------------------------- */
> > +/* Common API */
> > +
> > +/**
> > + * typec_altmode_notify - Communication between the OS and alternate mode driver
> > + * @adev: Handle to the alternate mode
> > + * @conf: Alternate mode specific configuration value
> > + * @data: Alternate mode specific data
> > + *
> > + * The primary purpose for this function is to allow the alternate mode drivers
> > + * to tell which pin configuration has been negotiated with the partner. That
> > + * information will then be used for example to configure the muxes.
> > + * Communication to the other direction is also possible, and low level device
> > + * drivers can also send notifications to the alternate mode drivers. The actual
> > + * communication will be specific for every SVID.
> > + */
> > +int typec_altmode_notify(struct typec_altmode *adev,
> > +			 unsigned long conf, void *data)
> > +{
> > +	struct altmode *altmode;
> > +	struct altmode *partner;
> > +	int ret;
> > +
> > +	/*
> > +	 * All SVID specific configuration values must start from
> > +	 * TYPEC_STATE_MODAL. The first values are reserved for the pin states
> > +	 * defined in USB Type-C specification: TYPEC_STATE_USB and
> > +	 * TYPEC_STATE_SAFE. We'll follow this rule even with modes that do not
> > +	 * require pin reconfiguration for the sake of simplicity.
> > +	 */
> > +	if (conf < TYPEC_STATE_MODAL)
> > +		return -EINVAL;
> > +
> > +	if (!adev)
> > +		return 0;
> > +
> > +	altmode = to_altmode(adev);
> > +
> > +	if (!altmode->partner)
> > +		return -ENODEV;
> > +
> > +	ret = typec_set_mode(typec_altmode2port(adev), (int)conf);
> > +	if (ret)
> > +		return ret;
> > +
> > +	partner = altmode->partner;
> > +
> > +	blocking_notifier_call_chain(is_typec_port(adev->dev.parent) ?
> > +				     &altmode->nh : &partner->nh,
> > +				     conf, data);
> > +
> > +	if (partner->ops && partner->ops->notify)
> > +		return partner->ops->notify(&partner->adev, conf, data);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_notify);
> > +
> > +/**
> > + * typec_altmode_enter - Enter Mode
> > + * @adev: The alternate mode
> > + *
> > + * The alternate mode drivers use this function to enter mode. The port drivers
> > + * use this to inform the alternate mode drivers that their mode has been
> > + * entered successfully.
> > + */
> > +int typec_altmode_enter(struct typec_altmode *adev)
> > +{
> > +	struct altmode *partner = to_altmode(adev)->partner;
> > +	struct typec_altmode *pdev = &partner->adev;
> > +	int ret;
> > +
> > +	if (is_typec_port(adev->dev.parent)) {
> > +		typec_altmode_update_active(pdev, pdev->mode, true);
> > +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> > +		goto enter_mode;
> > +	}
> > +
> > +	if (!pdev->active)
> > +		return -EPERM;
> > +
> > +	/* First moving to USB Safe State */
> > +	ret = typec_set_mode(typec_altmode2port(adev), TYPEC_STATE_SAFE);
> > +	if (ret)
> > +		return ret;
> > +
> > +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> > +
> > +enter_mode:
> > +	/* Enter Mode command */
> > +	if (partner->ops && partner->ops->enter)
> > +		partner->ops->enter(pdev);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_enter);
> > +
> > +/**
> > + * typec_altmode_enter - Exit Mode
> 
> typec_altmode_exit

Yes.

> > + * @adev: The alternate mode
> > + *
> > + * The alternate mode drivers use this function to exit mode. The port drivers
> > + * can also inform the alternate mode drivers with this function that the mode
> > + * was successfully exited.
> > + */
> > +int typec_altmode_exit(struct typec_altmode *adev)
> > +{
> > +	struct altmode *partner = to_altmode(adev)->partner;
> > +	struct typec_port *port = typec_altmode2port(adev);
> > +	struct typec_altmode *pdev = &partner->adev;
> > +	int ret;
> > +
> > +	/* In case of port, just calling the driver and exiting */
> > +	if (is_typec_port(adev->dev.parent)) {
> > +		typec_altmode_update_active(pdev, pdev->mode, false);
> > +		sysfs_notify(&pdev->dev.kobj, NULL, "active");
> > +
> > +		if (partner->ops && partner->ops->exit)
> > +			partner->ops->exit(pdev);
> > +		return 0;
> > +	}
> > +
> > +	/* Moving to USB Safe State */
> > +	ret = typec_set_mode(port, TYPEC_STATE_SAFE);
> > +	if (ret)
> > +		return ret;
> > +
> > +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_SAFE, NULL);
> > +
> > +	/* Exit Mode command */
> > +	if (partner->ops && partner->ops->exit)
> > +		partner->ops->exit(pdev);
> > +
> > +	/* Back to USB operation */
> > +	ret = typec_set_mode(port, TYPEC_STATE_USB);
> > +	if (ret)
> > +		return ret;
> > +
> > +	blocking_notifier_call_chain(&partner->nh, TYPEC_STATE_USB, NULL);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_exit);
> > +
> > +/**
> > + * typec_altmode_attention - Attention command
> > + * @adev: The alternate mode
> > + * @vdo: VDO for the Attention command
> > + *
> > + * Notifies the partner of @adev about Attention command.
> > + */
> > +void typec_altmode_attention(struct typec_altmode *adev, const u32 vdo)
> > +{
> > +	struct altmode *partner = to_altmode(adev)->partner;
> > +
> > +	if (partner && partner->ops && partner->ops->attention)
> > +		partner->ops->attention(&partner->adev, vdo);
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_attention);
> > +
> > +/**
> > + * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
> > + * @adev: Alternate mode handle
> > + * @header: VDM Header
> > + * @vdo: Array of Vendor Defined Data Objects
> > + * @count: Number of Data Objects
> > + *
> > + * The alternate mode drivers use this function for SVID specific communication
> > + * with the partner. The port drivers use it to deliver the Structured VDMs
> > + * received from the partners to the alternate mode drivers.
> > + */
> > +int typec_altmode_vdm(struct typec_altmode *adev,
> > +		      const u32 header, const u32 *vdo, int count)
> > +{
> > +	struct altmode *altmode;
> > +	struct altmode *partner;
> > +
> > +	if (!adev)
> > +		return 0;
> > +
> > +	altmode = to_altmode(adev);
> > +
> > +	if (!altmode->partner)
> > +		return -ENODEV;
> > +
> > +	partner = altmode->partner;
> > +
> > +	if (partner->ops && partner->ops->vdm)
> > +		return partner->ops->vdm(&partner->adev, header, vdo, count);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_vdm);
> > +
> > +void typec_altmode_register_ops(struct typec_altmode *adev,
> > +				const struct typec_altmode_ops *ops)
> > +{
> > +	to_altmode(adev)->ops = ops;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_register_ops);
> > +
> > +/* -------------------------------------------------------------------------- */
> > +/* API for the alternate mode drivers */
> > +
> > +/**
> > + * typec_altmode_get_plug - Find cable plug alternate mode
> > + * @adev: Handle to partner alternate mode
> > + * @index: Cable plug index
> > + *
> > + * Increment reference count for cable plug alternate mode device. Returns
> > + * handle to the cable plug alternate mode, or NULL if none is found.
> > + */
> > +struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
> > +					     int index)
> > +{
> > +	struct altmode *port = to_altmode(adev)->partner;
> > +
> > +	if (port->plug[index]) {
> > +		get_device(&port->plug[index]->adev.dev);
> > +		return &port->plug[index]->adev;
> > +	}
> > +
> > +	return NULL;
> > +}
> > +EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
> > +
> > +/**
> > + * typec_altmode_get_plug - Decrement cable plug alternate mode reference count
> 
> typec_altmode_put_plug

Yes.


Thanks,

[RFC PATCH v2 3/3] usb: typec: tcpm: Support for Alternate Modes

[Heikki Krogerus]

This adds more complete handling of VDMs and registration of
partner alternate modes, and introduces callbacks for
alternate mode operations.

Only DFP role is supported for now.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/typec/tcpm.c | 133 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 111 insertions(+), 22 deletions(-)

diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index bfb843ebffa6..34bf5c1f4d81 100644
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -158,13 +158,14 @@ enum pd_msg_request {
 /* Alternate mode support */
 
 #define SVID_DISCOVERY_MAX	16
+#define ALTMODE_DISCOVERY_MAX	(SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)
 
 struct pd_mode_data {
 	int svid_index;		/* current SVID index		*/
 	int nsvids;
 	u16 svids[SVID_DISCOVERY_MAX];
 	int altmodes;		/* number of alternate modes	*/
-	struct typec_altmode_desc altmode_desc[SVID_DISCOVERY_MAX];
+	struct typec_altmode_desc altmode_desc[ALTMODE_DISCOVERY_MAX];
 };
 
 struct tcpm_port {
@@ -280,8 +281,8 @@ struct tcpm_port {
 	/* Alternate mode data */
 
 	struct pd_mode_data mode_data;
-	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
-	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
+	struct typec_altmode *partner_altmode[ALTMODE_DISCOVERY_MAX];
+	struct typec_altmode *port_altmode[ALTMODE_DISCOVERY_MAX];
 
 	/* Deadline in jiffies to exit src_try_wait state */
 	unsigned long max_wait;
@@ -985,36 +986,53 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
 			 pmdata->altmodes, paltmode->svid,
 			 paltmode->mode, paltmode->vdo);
 
-		port->partner_altmode[pmdata->altmodes] =
-			typec_partner_register_altmode(port->partner, paltmode);
-		if (!port->partner_altmode[pmdata->altmodes]) {
-			tcpm_log(port,
-				 "Failed to register modes for SVID 0x%04x",
-				 paltmode->svid);
-			return;
-		}
 		pmdata->altmodes++;
 	}
 }
 
+static void tcpm_register_partner_altmodes(struct tcpm_port *port)
+{
+	struct pd_mode_data *modep = &port->mode_data;
+	struct typec_altmode *altmode;
+	int i;
+
+	for (i = 0; i < modep->altmodes; i++) {
+		altmode = typec_partner_register_altmode(port->partner,
+						&modep->altmode_desc[i]);
+		if (!altmode)
+			tcpm_log(port, "Failed to register partner SVID 0x%04x",
+				 modep->altmode_desc[i].svid);
+		port->partner_altmode[i] = altmode;
+	}
+}
+
 #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
 
 static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 			u32 *response)
 {
-	u32 p0 = le32_to_cpu(payload[0]);
-	int cmd_type = PD_VDO_CMDT(p0);
-	int cmd = PD_VDO_CMD(p0);
+	struct typec_altmode *altmode;
 	struct pd_mode_data *modep;
+	u32 p[PD_MAX_PAYLOAD];
 	int rlen = 0;
-	u16 svid;
+	int cmd_type;
+	int cmd;
 	int i;
 
+	for (i = 0; i < cnt; i++)
+		p[i] = le32_to_cpu(payload[i]);
+
+	cmd_type = PD_VDO_CMDT(p[0]);
+	cmd = PD_VDO_CMD(p[0]);
+
 	tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
-		 p0, cmd_type, cmd, cnt);
+		 p[0], cmd_type, cmd, cnt);
 
 	modep = &port->mode_data;
 
+	altmode = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
+				      PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));
+
 	switch (cmd_type) {
 	case CMDT_INIT:
 		switch (cmd) {
@@ -1036,17 +1054,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 		case CMD_EXIT_MODE:
 			break;
 		case CMD_ATTENTION:
-			break;
+			typec_altmode_attention(altmode, p[1]);
+			return 0;
 		default:
+			if (typec_altmode_vdm(altmode, p[0], &p[1], cnt) ==
+			    VDM_OK)
+				return 0;
 			break;
 		}
 		if (rlen >= 1) {
-			response[0] = p0 | VDO_CMDT(CMDT_RSP_ACK);
+			response[0] = p[0] | VDO_CMDT(CMDT_RSP_ACK);
 		} else if (rlen == 0) {
-			response[0] = p0 | VDO_CMDT(CMDT_RSP_NAK);
+			response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
 			rlen = 1;
 		} else {
-			response[0] = p0 | VDO_CMDT(CMDT_RSP_BUSY);
+			response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
 			rlen = 1;
 		}
 		break;
@@ -1079,20 +1101,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 			svdm_consume_modes(port, payload, cnt);
 			modep->svid_index++;
 			if (modep->svid_index < modep->nsvids) {
-				svid = modep->svids[modep->svid_index];
+				u16 svid = modep->svids[modep->svid_index];
 				response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
 				rlen = 1;
 			} else {
-				/* enter alternate mode if/when implemented */
+				tcpm_register_partner_altmodes(port);
 			}
 			break;
 		case CMD_ENTER_MODE:
+			typec_altmode_enter(altmode);
+			break;
+		case CMD_EXIT_MODE:
+			typec_altmode_exit(altmode);
 			break;
 		default:
+			typec_altmode_vdm(altmode, p[0], &p[1], cnt);
 			break;
 		}
 		break;
 	default:
+		typec_altmode_vdm(altmode, p[0], &p[1], cnt);
 		break;
 	}
 
@@ -1352,6 +1380,47 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
 	return 0;
 }
 
+static void tcpm_altmode_enter(struct typec_altmode *altmode)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
+	u32 header;
+
+	header = VDO(altmode->svid, 1, CMD_ENTER_MODE);
+	header |= VDO_OPOS(altmode->mode);
+
+	tcpm_queue_vdm(port, header, NULL, 0);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+}
+
+static void tcpm_altmode_exit(struct typec_altmode *altmode)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
+	u32 header;
+
+	header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
+	header |= VDO_OPOS(altmode->mode);
+
+	tcpm_queue_vdm(port, header, NULL, 0);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+}
+
+static int tcpm_altmode_vdm(struct typec_altmode *altmode,
+			    u32 header, const u32 *data, int count)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
+
+	tcpm_queue_vdm(port, header, data, count - 1);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+
+	return 0;
+}
+
+static const struct typec_altmode_ops tcpm_altmode_ops = {
+	.enter = tcpm_altmode_enter,
+	.exit = tcpm_altmode_exit,
+	.vdm = tcpm_altmode_vdm,
+};
+
 /*
  * PD (data, control) command handling functions
  */
@@ -3479,6 +3548,23 @@ static void tcpm_init(struct tcpm_port *port)
 	tcpm_set_state(port, PORT_RESET, 0);
 }
 
+static int tcpm_activate_mode(struct typec_altmode *alt, int activate)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(alt);
+	u32 header;
+
+	header = VDO(cpu_to_le16(alt->svid), 1,
+		     activate ? CMD_ENTER_MODE : CMD_EXIT_MODE);
+	header |= VDO_OPOS(alt->mode);
+
+	mutex_lock(&port->lock);
+	tcpm_queue_vdm(port, header, NULL, 0);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+	mutex_unlock(&port->lock);
+
+	return 0;
+}
+
 static int tcpm_port_type_set(const struct typec_capability *cap,
 			      enum typec_port_type type)
 {
@@ -3671,6 +3757,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 	port->typec_caps.pr_set = tcpm_pr_set;
 	port->typec_caps.vconn_set = tcpm_vconn_set;
 	port->typec_caps.try_role = tcpm_try_role;
+	port->typec_caps.activate_mode = tcpm_activate_mode;
 	port->typec_caps.port_type_set = tcpm_port_type_set;
 
 	port->partner_desc.identity = &port->partner_ident;
@@ -3703,6 +3790,8 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 					 dev_name(dev), paltmode->svid);
 				break;
 			}
+			typec_altmode_set_drvdata(alt, port);
+			typec_altmode_register_ops(alt, &tcpm_altmode_ops);
 			port->port_altmode[i] = alt;
 			i++;
 			paltmode++;
-- 
2.16.1

[RFC,v2,3/3] usb: typec: tcpm: Support for Alternate Modes

[Heikki Krogerus]

This adds more complete handling of VDMs and registration of
partner alternate modes, and introduces callbacks for
alternate mode operations.

Only DFP role is supported for now.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/usb/typec/tcpm.c | 133 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 111 insertions(+), 22 deletions(-)

diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index bfb843ebffa6..34bf5c1f4d81 100644
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -158,13 +158,14 @@ enum pd_msg_request {
 /* Alternate mode support */
 
 #define SVID_DISCOVERY_MAX	16
+#define ALTMODE_DISCOVERY_MAX	(SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)
 
 struct pd_mode_data {
 	int svid_index;		/* current SVID index		*/
 	int nsvids;
 	u16 svids[SVID_DISCOVERY_MAX];
 	int altmodes;		/* number of alternate modes	*/
-	struct typec_altmode_desc altmode_desc[SVID_DISCOVERY_MAX];
+	struct typec_altmode_desc altmode_desc[ALTMODE_DISCOVERY_MAX];
 };
 
 struct tcpm_port {
@@ -280,8 +281,8 @@ struct tcpm_port {
 	/* Alternate mode data */
 
 	struct pd_mode_data mode_data;
-	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
-	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
+	struct typec_altmode *partner_altmode[ALTMODE_DISCOVERY_MAX];
+	struct typec_altmode *port_altmode[ALTMODE_DISCOVERY_MAX];
 
 	/* Deadline in jiffies to exit src_try_wait state */
 	unsigned long max_wait;
@@ -985,36 +986,53 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
 			 pmdata->altmodes, paltmode->svid,
 			 paltmode->mode, paltmode->vdo);
 
-		port->partner_altmode[pmdata->altmodes] =
-			typec_partner_register_altmode(port->partner, paltmode);
-		if (!port->partner_altmode[pmdata->altmodes]) {
-			tcpm_log(port,
-				 "Failed to register modes for SVID 0x%04x",
-				 paltmode->svid);
-			return;
-		}
 		pmdata->altmodes++;
 	}
 }
 
+static void tcpm_register_partner_altmodes(struct tcpm_port *port)
+{
+	struct pd_mode_data *modep = &port->mode_data;
+	struct typec_altmode *altmode;
+	int i;
+
+	for (i = 0; i < modep->altmodes; i++) {
+		altmode = typec_partner_register_altmode(port->partner,
+						&modep->altmode_desc[i]);
+		if (!altmode)
+			tcpm_log(port, "Failed to register partner SVID 0x%04x",
+				 modep->altmode_desc[i].svid);
+		port->partner_altmode[i] = altmode;
+	}
+}
+
 #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
 
 static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 			u32 *response)
 {
-	u32 p0 = le32_to_cpu(payload[0]);
-	int cmd_type = PD_VDO_CMDT(p0);
-	int cmd = PD_VDO_CMD(p0);
+	struct typec_altmode *altmode;
 	struct pd_mode_data *modep;
+	u32 p[PD_MAX_PAYLOAD];
 	int rlen = 0;
-	u16 svid;
+	int cmd_type;
+	int cmd;
 	int i;
 
+	for (i = 0; i < cnt; i++)
+		p[i] = le32_to_cpu(payload[i]);
+
+	cmd_type = PD_VDO_CMDT(p[0]);
+	cmd = PD_VDO_CMD(p[0]);
+
 	tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
-		 p0, cmd_type, cmd, cnt);
+		 p[0], cmd_type, cmd, cnt);
 
 	modep = &port->mode_data;
 
+	altmode = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
+				      PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));
+
 	switch (cmd_type) {
 	case CMDT_INIT:
 		switch (cmd) {
@@ -1036,17 +1054,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 		case CMD_EXIT_MODE:
 			break;
 		case CMD_ATTENTION:
-			break;
+			typec_altmode_attention(altmode, p[1]);
+			return 0;
 		default:
+			if (typec_altmode_vdm(altmode, p[0], &p[1], cnt) ==
+			    VDM_OK)
+				return 0;
 			break;
 		}
 		if (rlen >= 1) {
-			response[0] = p0 | VDO_CMDT(CMDT_RSP_ACK);
+			response[0] = p[0] | VDO_CMDT(CMDT_RSP_ACK);
 		} else if (rlen == 0) {
-			response[0] = p0 | VDO_CMDT(CMDT_RSP_NAK);
+			response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
 			rlen = 1;
 		} else {
-			response[0] = p0 | VDO_CMDT(CMDT_RSP_BUSY);
+			response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
 			rlen = 1;
 		}
 		break;
@@ -1079,20 +1101,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
 			svdm_consume_modes(port, payload, cnt);
 			modep->svid_index++;
 			if (modep->svid_index < modep->nsvids) {
-				svid = modep->svids[modep->svid_index];
+				u16 svid = modep->svids[modep->svid_index];
 				response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
 				rlen = 1;
 			} else {
-				/* enter alternate mode if/when implemented */
+				tcpm_register_partner_altmodes(port);
 			}
 			break;
 		case CMD_ENTER_MODE:
+			typec_altmode_enter(altmode);
+			break;
+		case CMD_EXIT_MODE:
+			typec_altmode_exit(altmode);
 			break;
 		default:
+			typec_altmode_vdm(altmode, p[0], &p[1], cnt);
 			break;
 		}
 		break;
 	default:
+		typec_altmode_vdm(altmode, p[0], &p[1], cnt);
 		break;
 	}
 
@@ -1352,6 +1380,47 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
 	return 0;
 }
 
+static void tcpm_altmode_enter(struct typec_altmode *altmode)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
+	u32 header;
+
+	header = VDO(altmode->svid, 1, CMD_ENTER_MODE);
+	header |= VDO_OPOS(altmode->mode);
+
+	tcpm_queue_vdm(port, header, NULL, 0);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+}
+
+static void tcpm_altmode_exit(struct typec_altmode *altmode)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
+	u32 header;
+
+	header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
+	header |= VDO_OPOS(altmode->mode);
+
+	tcpm_queue_vdm(port, header, NULL, 0);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+}
+
+static int tcpm_altmode_vdm(struct typec_altmode *altmode,
+			    u32 header, const u32 *data, int count)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
+
+	tcpm_queue_vdm(port, header, data, count - 1);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+
+	return 0;
+}
+
+static const struct typec_altmode_ops tcpm_altmode_ops = {
+	.enter = tcpm_altmode_enter,
+	.exit = tcpm_altmode_exit,
+	.vdm = tcpm_altmode_vdm,
+};
+
 /*
  * PD (data, control) command handling functions
  */
@@ -3479,6 +3548,23 @@ static void tcpm_init(struct tcpm_port *port)
 	tcpm_set_state(port, PORT_RESET, 0);
 }
 
+static int tcpm_activate_mode(struct typec_altmode *alt, int activate)
+{
+	struct tcpm_port *port = typec_altmode_get_drvdata(alt);
+	u32 header;
+
+	header = VDO(cpu_to_le16(alt->svid), 1,
+		     activate ? CMD_ENTER_MODE : CMD_EXIT_MODE);
+	header |= VDO_OPOS(alt->mode);
+
+	mutex_lock(&port->lock);
+	tcpm_queue_vdm(port, header, NULL, 0);
+	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
+	mutex_unlock(&port->lock);
+
+	return 0;
+}
+
 static int tcpm_port_type_set(const struct typec_capability *cap,
 			      enum typec_port_type type)
 {
@@ -3671,6 +3757,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 	port->typec_caps.pr_set = tcpm_pr_set;
 	port->typec_caps.vconn_set = tcpm_vconn_set;
 	port->typec_caps.try_role = tcpm_try_role;
+	port->typec_caps.activate_mode = tcpm_activate_mode;
 	port->typec_caps.port_type_set = tcpm_port_type_set;
 
 	port->partner_desc.identity = &port->partner_ident;
@@ -3703,6 +3790,8 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
 					 dev_name(dev), paltmode->svid);
 				break;
 			}
+			typec_altmode_set_drvdata(alt, port);
+			typec_altmode_register_ops(alt, &tcpm_altmode_ops);
 			port->port_altmode[i] = alt;
 			i++;
 			paltmode++;

Re: [RFC PATCH v2 3/3] usb: typec: tcpm: Support for Alternate Modes

[Guenter Roeck]

On Fri, Mar 09, 2018 at 06:19:18PM +0300, Heikki Krogerus wrote:
> This adds more complete handling of VDMs and registration of
> partner alternate modes, and introduces callbacks for
> alternate mode operations.
> 
> Only DFP role is supported for now.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/usb/typec/tcpm.c | 133 +++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 111 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> index bfb843ebffa6..34bf5c1f4d81 100644
> --- a/drivers/usb/typec/tcpm.c
> +++ b/drivers/usb/typec/tcpm.c
> @@ -158,13 +158,14 @@ enum pd_msg_request {
>  /* Alternate mode support */
>  
>  #define SVID_DISCOVERY_MAX	16
> +#define ALTMODE_DISCOVERY_MAX	(SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)
>  
>  struct pd_mode_data {
>  	int svid_index;		/* current SVID index		*/
>  	int nsvids;
>  	u16 svids[SVID_DISCOVERY_MAX];
>  	int altmodes;		/* number of alternate modes	*/
> -	struct typec_altmode_desc altmode_desc[SVID_DISCOVERY_MAX];
> +	struct typec_altmode_desc altmode_desc[ALTMODE_DISCOVERY_MAX];
>  };
>  
>  struct tcpm_port {
> @@ -280,8 +281,8 @@ struct tcpm_port {
>  	/* Alternate mode data */
>  
>  	struct pd_mode_data mode_data;
> -	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
> -	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
> +	struct typec_altmode *partner_altmode[ALTMODE_DISCOVERY_MAX];
> +	struct typec_altmode *port_altmode[ALTMODE_DISCOVERY_MAX];
>  
>  	/* Deadline in jiffies to exit src_try_wait state */
>  	unsigned long max_wait;
> @@ -985,36 +986,53 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
>  			 pmdata->altmodes, paltmode->svid,
>  			 paltmode->mode, paltmode->vdo);
>  
> -		port->partner_altmode[pmdata->altmodes] =
> -			typec_partner_register_altmode(port->partner, paltmode);
> -		if (!port->partner_altmode[pmdata->altmodes]) {
> -			tcpm_log(port,
> -				 "Failed to register modes for SVID 0x%04x",
> -				 paltmode->svid);
> -			return;
> -		}
>  		pmdata->altmodes++;
>  	}
>  }
>  
> +static void tcpm_register_partner_altmodes(struct tcpm_port *port)
> +{
> +	struct pd_mode_data *modep = &port->mode_data;
> +	struct typec_altmode *altmode;
> +	int i;
> +
> +	for (i = 0; i < modep->altmodes; i++) {
> +		altmode = typec_partner_register_altmode(port->partner,
> +						&modep->altmode_desc[i]);
> +		if (!altmode)
> +			tcpm_log(port, "Failed to register partner SVID 0x%04x",
> +				 modep->altmode_desc[i].svid);
> +		port->partner_altmode[i] = altmode;
> +	}
> +}
> +
>  #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
>  
>  static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
>  			u32 *response)
>  {
> -	u32 p0 = le32_to_cpu(payload[0]);
> -	int cmd_type = PD_VDO_CMDT(p0);
> -	int cmd = PD_VDO_CMD(p0);
> +	struct typec_altmode *altmode;
>  	struct pd_mode_data *modep;
> +	u32 p[PD_MAX_PAYLOAD];
>  	int rlen = 0;
> -	u16 svid;
> +	int cmd_type;
> +	int cmd;
>  	int i;
>  
> +	for (i = 0; i < cnt; i++)
> +		p[i] = le32_to_cpu(payload[i]);
> +
> +	cmd_type = PD_VDO_CMDT(p[0]);
> +	cmd = PD_VDO_CMD(p[0]);
> +
>  	tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
> -		 p0, cmd_type, cmd, cnt);
> +		 p[0], cmd_type, cmd, cnt);
>  
>  	modep = &port->mode_data;
>  
> +	altmode = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
> +				      PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));

This can return NULL ...

> +
>  	switch (cmd_type) {
>  	case CMDT_INIT:
>  		switch (cmd) {
> @@ -1036,17 +1054,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
>  		case CMD_EXIT_MODE:
>  			break;
>  		case CMD_ATTENTION:
> -			break;
> +			typec_altmode_attention(altmode, p[1]);

... and NULL is not handled by typec_altmode_attention().

> +			return 0;
>  		default:
> +			if (typec_altmode_vdm(altmode, p[0], &p[1], cnt) ==
> +			    VDM_OK)

typec_altmode_vdm() returns old fashioned error messages.
Not sure what it is supposed to return, though.

> +				return 0;
>  			break;
>  		}
>  		if (rlen >= 1) {
> -			response[0] = p0 | VDO_CMDT(CMDT_RSP_ACK);
> +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_ACK);
>  		} else if (rlen == 0) {
> -			response[0] = p0 | VDO_CMDT(CMDT_RSP_NAK);
> +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
>  			rlen = 1;
>  		} else {
> -			response[0] = p0 | VDO_CMDT(CMDT_RSP_BUSY);
> +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
>  			rlen = 1;
>  		}
>  		break;
> @@ -1079,20 +1101,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
>  			svdm_consume_modes(port, payload, cnt);
>  			modep->svid_index++;
>  			if (modep->svid_index < modep->nsvids) {
> -				svid = modep->svids[modep->svid_index];
> +				u16 svid = modep->svids[modep->svid_index];
>  				response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
>  				rlen = 1;
>  			} else {
> -				/* enter alternate mode if/when implemented */
> +				tcpm_register_partner_altmodes(port);
>  			}
>  			break;
>  		case CMD_ENTER_MODE:
> +			typec_altmode_enter(altmode);

typec_altmode_enter() don't handle altmode == NULL.
No error handling ?

> +			break;
> +		case CMD_EXIT_MODE:
> +			typec_altmode_exit(altmode);

Doesn't handle NULL. Error handling ?

>  			break;
>  		default:
> +			typec_altmode_vdm(altmode, p[0], &p[1], cnt);
>  			break;
>  		}
>  		break;
>  	default:
> +		typec_altmode_vdm(altmode, p[0], &p[1], cnt);
>  		break;
>  	}
>  
> @@ -1352,6 +1380,47 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
>  	return 0;
>  }
>  
> +static void tcpm_altmode_enter(struct typec_altmode *altmode)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> +	u32 header;
> +
> +	header = VDO(altmode->svid, 1, CMD_ENTER_MODE);
> +	header |= VDO_OPOS(altmode->mode);
> +
> +	tcpm_queue_vdm(port, header, NULL, 0);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +}
> +
> +static void tcpm_altmode_exit(struct typec_altmode *altmode)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> +	u32 header;
> +
> +	header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
> +	header |= VDO_OPOS(altmode->mode);
> +
> +	tcpm_queue_vdm(port, header, NULL, 0);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +}
> +
> +static int tcpm_altmode_vdm(struct typec_altmode *altmode,
> +			    u32 header, const u32 *data, int count)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> +
> +	tcpm_queue_vdm(port, header, data, count - 1);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +
> +	return 0;
> +}
> +
> +static const struct typec_altmode_ops tcpm_altmode_ops = {
> +	.enter = tcpm_altmode_enter,
> +	.exit = tcpm_altmode_exit,
> +	.vdm = tcpm_altmode_vdm,
> +};
> +
>  /*
>   * PD (data, control) command handling functions
>   */
> @@ -3479,6 +3548,23 @@ static void tcpm_init(struct tcpm_port *port)
>  	tcpm_set_state(port, PORT_RESET, 0);
>  }
>  
> +static int tcpm_activate_mode(struct typec_altmode *alt, int activate)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(alt);
> +	u32 header;
> +
> +	header = VDO(cpu_to_le16(alt->svid), 1,
> +		     activate ? CMD_ENTER_MODE : CMD_EXIT_MODE);
> +	header |= VDO_OPOS(alt->mode);
> +
> +	mutex_lock(&port->lock);
> +	tcpm_queue_vdm(port, header, NULL, 0);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +	mutex_unlock(&port->lock);

Some of the above functions are port mutex protected, some are not.
Is this on purpose ?

> +
> +	return 0;
> +}
> +
>  static int tcpm_port_type_set(const struct typec_capability *cap,
>  			      enum typec_port_type type)
>  {
> @@ -3671,6 +3757,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
>  	port->typec_caps.pr_set = tcpm_pr_set;
>  	port->typec_caps.vconn_set = tcpm_vconn_set;
>  	port->typec_caps.try_role = tcpm_try_role;
> +	port->typec_caps.activate_mode = tcpm_activate_mode;
>  	port->typec_caps.port_type_set = tcpm_port_type_set;
>  
>  	port->partner_desc.identity = &port->partner_ident;
> @@ -3703,6 +3790,8 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
>  					 dev_name(dev), paltmode->svid);
>  				break;
>  			}
> +			typec_altmode_set_drvdata(alt, port);
> +			typec_altmode_register_ops(alt, &tcpm_altmode_ops);
>  			port->port_altmode[i] = alt;
>  			i++;
>  			paltmode++;
> -- 
> 2.16.1
> 

[RFC,v2,3/3] usb: typec: tcpm: Support for Alternate Modes

[Guenter Roeck]

On Fri, Mar 09, 2018 at 06:19:18PM +0300, Heikki Krogerus wrote:
> This adds more complete handling of VDMs and registration of
> partner alternate modes, and introduces callbacks for
> alternate mode operations.
> 
> Only DFP role is supported for now.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/usb/typec/tcpm.c | 133 +++++++++++++++++++++++++++++++++++++++--------
>  1 file changed, 111 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> index bfb843ebffa6..34bf5c1f4d81 100644
> --- a/drivers/usb/typec/tcpm.c
> +++ b/drivers/usb/typec/tcpm.c
> @@ -158,13 +158,14 @@ enum pd_msg_request {
>  /* Alternate mode support */
>  
>  #define SVID_DISCOVERY_MAX	16
> +#define ALTMODE_DISCOVERY_MAX	(SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)
>  
>  struct pd_mode_data {
>  	int svid_index;		/* current SVID index		*/
>  	int nsvids;
>  	u16 svids[SVID_DISCOVERY_MAX];
>  	int altmodes;		/* number of alternate modes	*/
> -	struct typec_altmode_desc altmode_desc[SVID_DISCOVERY_MAX];
> +	struct typec_altmode_desc altmode_desc[ALTMODE_DISCOVERY_MAX];
>  };
>  
>  struct tcpm_port {
> @@ -280,8 +281,8 @@ struct tcpm_port {
>  	/* Alternate mode data */
>  
>  	struct pd_mode_data mode_data;
> -	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
> -	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
> +	struct typec_altmode *partner_altmode[ALTMODE_DISCOVERY_MAX];
> +	struct typec_altmode *port_altmode[ALTMODE_DISCOVERY_MAX];
>  
>  	/* Deadline in jiffies to exit src_try_wait state */
>  	unsigned long max_wait;
> @@ -985,36 +986,53 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
>  			 pmdata->altmodes, paltmode->svid,
>  			 paltmode->mode, paltmode->vdo);
>  
> -		port->partner_altmode[pmdata->altmodes] =
> -			typec_partner_register_altmode(port->partner, paltmode);
> -		if (!port->partner_altmode[pmdata->altmodes]) {
> -			tcpm_log(port,
> -				 "Failed to register modes for SVID 0x%04x",
> -				 paltmode->svid);
> -			return;
> -		}
>  		pmdata->altmodes++;
>  	}
>  }
>  
> +static void tcpm_register_partner_altmodes(struct tcpm_port *port)
> +{
> +	struct pd_mode_data *modep = &port->mode_data;
> +	struct typec_altmode *altmode;
> +	int i;
> +
> +	for (i = 0; i < modep->altmodes; i++) {
> +		altmode = typec_partner_register_altmode(port->partner,
> +						&modep->altmode_desc[i]);
> +		if (!altmode)
> +			tcpm_log(port, "Failed to register partner SVID 0x%04x",
> +				 modep->altmode_desc[i].svid);
> +		port->partner_altmode[i] = altmode;
> +	}
> +}
> +
>  #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
>  
>  static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
>  			u32 *response)
>  {
> -	u32 p0 = le32_to_cpu(payload[0]);
> -	int cmd_type = PD_VDO_CMDT(p0);
> -	int cmd = PD_VDO_CMD(p0);
> +	struct typec_altmode *altmode;
>  	struct pd_mode_data *modep;
> +	u32 p[PD_MAX_PAYLOAD];
>  	int rlen = 0;
> -	u16 svid;
> +	int cmd_type;
> +	int cmd;
>  	int i;
>  
> +	for (i = 0; i < cnt; i++)
> +		p[i] = le32_to_cpu(payload[i]);
> +
> +	cmd_type = PD_VDO_CMDT(p[0]);
> +	cmd = PD_VDO_CMD(p[0]);
> +
>  	tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
> -		 p0, cmd_type, cmd, cnt);
> +		 p[0], cmd_type, cmd, cnt);
>  
>  	modep = &port->mode_data;
>  
> +	altmode = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
> +				      PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));

This can return NULL ...

> +
>  	switch (cmd_type) {
>  	case CMDT_INIT:
>  		switch (cmd) {
> @@ -1036,17 +1054,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
>  		case CMD_EXIT_MODE:
>  			break;
>  		case CMD_ATTENTION:
> -			break;
> +			typec_altmode_attention(altmode, p[1]);

... and NULL is not handled by typec_altmode_attention().

> +			return 0;
>  		default:
> +			if (typec_altmode_vdm(altmode, p[0], &p[1], cnt) ==
> +			    VDM_OK)

typec_altmode_vdm() returns old fashioned error messages.
Not sure what it is supposed to return, though.

> +				return 0;
>  			break;
>  		}
>  		if (rlen >= 1) {
> -			response[0] = p0 | VDO_CMDT(CMDT_RSP_ACK);
> +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_ACK);
>  		} else if (rlen == 0) {
> -			response[0] = p0 | VDO_CMDT(CMDT_RSP_NAK);
> +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
>  			rlen = 1;
>  		} else {
> -			response[0] = p0 | VDO_CMDT(CMDT_RSP_BUSY);
> +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
>  			rlen = 1;
>  		}
>  		break;
> @@ -1079,20 +1101,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
>  			svdm_consume_modes(port, payload, cnt);
>  			modep->svid_index++;
>  			if (modep->svid_index < modep->nsvids) {
> -				svid = modep->svids[modep->svid_index];
> +				u16 svid = modep->svids[modep->svid_index];
>  				response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
>  				rlen = 1;
>  			} else {
> -				/* enter alternate mode if/when implemented */
> +				tcpm_register_partner_altmodes(port);
>  			}
>  			break;
>  		case CMD_ENTER_MODE:
> +			typec_altmode_enter(altmode);

typec_altmode_enter() don't handle altmode == NULL.
No error handling ?

> +			break;
> +		case CMD_EXIT_MODE:
> +			typec_altmode_exit(altmode);

Doesn't handle NULL. Error handling ?

>  			break;
>  		default:
> +			typec_altmode_vdm(altmode, p[0], &p[1], cnt);
>  			break;
>  		}
>  		break;
>  	default:
> +		typec_altmode_vdm(altmode, p[0], &p[1], cnt);
>  		break;
>  	}
>  
> @@ -1352,6 +1380,47 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
>  	return 0;
>  }
>  
> +static void tcpm_altmode_enter(struct typec_altmode *altmode)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> +	u32 header;
> +
> +	header = VDO(altmode->svid, 1, CMD_ENTER_MODE);
> +	header |= VDO_OPOS(altmode->mode);
> +
> +	tcpm_queue_vdm(port, header, NULL, 0);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +}
> +
> +static void tcpm_altmode_exit(struct typec_altmode *altmode)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> +	u32 header;
> +
> +	header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
> +	header |= VDO_OPOS(altmode->mode);
> +
> +	tcpm_queue_vdm(port, header, NULL, 0);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +}
> +
> +static int tcpm_altmode_vdm(struct typec_altmode *altmode,
> +			    u32 header, const u32 *data, int count)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> +
> +	tcpm_queue_vdm(port, header, data, count - 1);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +
> +	return 0;
> +}
> +
> +static const struct typec_altmode_ops tcpm_altmode_ops = {
> +	.enter = tcpm_altmode_enter,
> +	.exit = tcpm_altmode_exit,
> +	.vdm = tcpm_altmode_vdm,
> +};
> +
>  /*
>   * PD (data, control) command handling functions
>   */
> @@ -3479,6 +3548,23 @@ static void tcpm_init(struct tcpm_port *port)
>  	tcpm_set_state(port, PORT_RESET, 0);
>  }
>  
> +static int tcpm_activate_mode(struct typec_altmode *alt, int activate)
> +{
> +	struct tcpm_port *port = typec_altmode_get_drvdata(alt);
> +	u32 header;
> +
> +	header = VDO(cpu_to_le16(alt->svid), 1,
> +		     activate ? CMD_ENTER_MODE : CMD_EXIT_MODE);
> +	header |= VDO_OPOS(alt->mode);
> +
> +	mutex_lock(&port->lock);
> +	tcpm_queue_vdm(port, header, NULL, 0);
> +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +	mutex_unlock(&port->lock);

Some of the above functions are port mutex protected, some are not.
Is this on purpose ?

> +
> +	return 0;
> +}
> +
>  static int tcpm_port_type_set(const struct typec_capability *cap,
>  			      enum typec_port_type type)
>  {
> @@ -3671,6 +3757,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
>  	port->typec_caps.pr_set = tcpm_pr_set;
>  	port->typec_caps.vconn_set = tcpm_vconn_set;
>  	port->typec_caps.try_role = tcpm_try_role;
> +	port->typec_caps.activate_mode = tcpm_activate_mode;
>  	port->typec_caps.port_type_set = tcpm_port_type_set;
>  
>  	port->partner_desc.identity = &port->partner_ident;
> @@ -3703,6 +3790,8 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
>  					 dev_name(dev), paltmode->svid);
>  				break;
>  			}
> +			typec_altmode_set_drvdata(alt, port);
> +			typec_altmode_register_ops(alt, &tcpm_altmode_ops);
>  			port->port_altmode[i] = alt;
>  			i++;
>  			paltmode++;
> -- 
> 2.16.1
>
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Re: [RFC PATCH v2 3/3] usb: typec: tcpm: Support for Alternate Modes

[Heikki Krogerus]

Hi Guenter,

On Fri, Mar 16, 2018 at 02:32:06PM -0700, Guenter Roeck wrote:
> On Fri, Mar 09, 2018 at 06:19:18PM +0300, Heikki Krogerus wrote:
> > This adds more complete handling of VDMs and registration of
> > partner alternate modes, and introduces callbacks for
> > alternate mode operations.
> > 
> > Only DFP role is supported for now.
> > 
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > ---
> >  drivers/usb/typec/tcpm.c | 133 +++++++++++++++++++++++++++++++++++++++--------
> >  1 file changed, 111 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> > index bfb843ebffa6..34bf5c1f4d81 100644
> > --- a/drivers/usb/typec/tcpm.c
> > +++ b/drivers/usb/typec/tcpm.c
> > @@ -158,13 +158,14 @@ enum pd_msg_request {
> >  /* Alternate mode support */
> >  
> >  #define SVID_DISCOVERY_MAX	16
> > +#define ALTMODE_DISCOVERY_MAX	(SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)
> >  
> >  struct pd_mode_data {
> >  	int svid_index;		/* current SVID index		*/
> >  	int nsvids;
> >  	u16 svids[SVID_DISCOVERY_MAX];
> >  	int altmodes;		/* number of alternate modes	*/
> > -	struct typec_altmode_desc altmode_desc[SVID_DISCOVERY_MAX];
> > +	struct typec_altmode_desc altmode_desc[ALTMODE_DISCOVERY_MAX];
> >  };
> >  
> >  struct tcpm_port {
> > @@ -280,8 +281,8 @@ struct tcpm_port {
> >  	/* Alternate mode data */
> >  
> >  	struct pd_mode_data mode_data;
> > -	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
> > -	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
> > +	struct typec_altmode *partner_altmode[ALTMODE_DISCOVERY_MAX];
> > +	struct typec_altmode *port_altmode[ALTMODE_DISCOVERY_MAX];
> >  
> >  	/* Deadline in jiffies to exit src_try_wait state */
> >  	unsigned long max_wait;
> > @@ -985,36 +986,53 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
> >  			 pmdata->altmodes, paltmode->svid,
> >  			 paltmode->mode, paltmode->vdo);
> >  
> > -		port->partner_altmode[pmdata->altmodes] =
> > -			typec_partner_register_altmode(port->partner, paltmode);
> > -		if (!port->partner_altmode[pmdata->altmodes]) {
> > -			tcpm_log(port,
> > -				 "Failed to register modes for SVID 0x%04x",
> > -				 paltmode->svid);
> > -			return;
> > -		}
> >  		pmdata->altmodes++;
> >  	}
> >  }
> >  
> > +static void tcpm_register_partner_altmodes(struct tcpm_port *port)
> > +{
> > +	struct pd_mode_data *modep = &port->mode_data;
> > +	struct typec_altmode *altmode;
> > +	int i;
> > +
> > +	for (i = 0; i < modep->altmodes; i++) {
> > +		altmode = typec_partner_register_altmode(port->partner,
> > +						&modep->altmode_desc[i]);
> > +		if (!altmode)
> > +			tcpm_log(port, "Failed to register partner SVID 0x%04x",
> > +				 modep->altmode_desc[i].svid);
> > +		port->partner_altmode[i] = altmode;
> > +	}
> > +}
> > +
> >  #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
> >  
> >  static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> >  			u32 *response)
> >  {
> > -	u32 p0 = le32_to_cpu(payload[0]);
> > -	int cmd_type = PD_VDO_CMDT(p0);
> > -	int cmd = PD_VDO_CMD(p0);
> > +	struct typec_altmode *altmode;
> >  	struct pd_mode_data *modep;
> > +	u32 p[PD_MAX_PAYLOAD];
> >  	int rlen = 0;
> > -	u16 svid;
> > +	int cmd_type;
> > +	int cmd;
> >  	int i;
> >  
> > +	for (i = 0; i < cnt; i++)
> > +		p[i] = le32_to_cpu(payload[i]);
> > +
> > +	cmd_type = PD_VDO_CMDT(p[0]);
> > +	cmd = PD_VDO_CMD(p[0]);
> > +
> >  	tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
> > -		 p0, cmd_type, cmd, cnt);
> > +		 p[0], cmd_type, cmd, cnt);
> >  
> >  	modep = &port->mode_data;
> >  
> > +	altmode = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
> > +				      PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));
> 
> This can return NULL ...
> 
> > +
> >  	switch (cmd_type) {
> >  	case CMDT_INIT:
> >  		switch (cmd) {
> > @@ -1036,17 +1054,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> >  		case CMD_EXIT_MODE:
> >  			break;
> >  		case CMD_ATTENTION:
> > -			break;
> > +			typec_altmode_attention(altmode, p[1]);
> 
> ... and NULL is not handled by typec_altmode_attention().

True.

> > +			return 0;
> >  		default:
> > +			if (typec_altmode_vdm(altmode, p[0], &p[1], cnt) ==
> > +			    VDM_OK)
> 
> typec_altmode_vdm() returns old fashioned error messages.
> Not sure what it is supposed to return, though.

The idea was that the alternate mode driver can inform the port driver
that it not support a specific VDM. In that case we need to NAK.

I'll think about this a bit more.

> > +				return 0;
> >  			break;
> >  		}
> >  		if (rlen >= 1) {
> > -			response[0] = p0 | VDO_CMDT(CMDT_RSP_ACK);
> > +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_ACK);
> >  		} else if (rlen == 0) {
> > -			response[0] = p0 | VDO_CMDT(CMDT_RSP_NAK);
> > +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
> >  			rlen = 1;
> >  		} else {
> > -			response[0] = p0 | VDO_CMDT(CMDT_RSP_BUSY);
> > +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
> >  			rlen = 1;
> >  		}
> >  		break;
> > @@ -1079,20 +1101,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> >  			svdm_consume_modes(port, payload, cnt);
> >  			modep->svid_index++;
> >  			if (modep->svid_index < modep->nsvids) {
> > -				svid = modep->svids[modep->svid_index];
> > +				u16 svid = modep->svids[modep->svid_index];
> >  				response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
> >  				rlen = 1;
> >  			} else {
> > -				/* enter alternate mode if/when implemented */
> > +				tcpm_register_partner_altmodes(port);
> >  			}
> >  			break;
> >  		case CMD_ENTER_MODE:
> > +			typec_altmode_enter(altmode);
> 
> typec_altmode_enter() don't handle altmode == NULL.

True. I'll fix that as well.

> No error handling ?
> 
> > +			break;
> > +		case CMD_EXIT_MODE:
> > +			typec_altmode_exit(altmode);
> 
> Doesn't handle NULL. Error handling ?

True, and I'll add error handling for there.

> >  			break;
> >  		default:
> > +			typec_altmode_vdm(altmode, p[0], &p[1], cnt);
> >  			break;
> >  		}
> >  		break;
> >  	default:
> > +		typec_altmode_vdm(altmode, p[0], &p[1], cnt);
> >  		break;
> >  	}
> >  
> > @@ -1352,6 +1380,47 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
> >  	return 0;
> >  }
> >  
> > +static void tcpm_altmode_enter(struct typec_altmode *altmode)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> > +	u32 header;
> > +
> > +	header = VDO(altmode->svid, 1, CMD_ENTER_MODE);
> > +	header |= VDO_OPOS(altmode->mode);
> > +
> > +	tcpm_queue_vdm(port, header, NULL, 0);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +}
> > +
> > +static void tcpm_altmode_exit(struct typec_altmode *altmode)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> > +	u32 header;
> > +
> > +	header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
> > +	header |= VDO_OPOS(altmode->mode);
> > +
> > +	tcpm_queue_vdm(port, header, NULL, 0);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +}
> > +
> > +static int tcpm_altmode_vdm(struct typec_altmode *altmode,
> > +			    u32 header, const u32 *data, int count)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> > +
> > +	tcpm_queue_vdm(port, header, data, count - 1);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct typec_altmode_ops tcpm_altmode_ops = {
> > +	.enter = tcpm_altmode_enter,
> > +	.exit = tcpm_altmode_exit,
> > +	.vdm = tcpm_altmode_vdm,
> > +};
> > +
> >  /*
> >   * PD (data, control) command handling functions
> >   */
> > @@ -3479,6 +3548,23 @@ static void tcpm_init(struct tcpm_port *port)
> >  	tcpm_set_state(port, PORT_RESET, 0);
> >  }
> >  
> > +static int tcpm_activate_mode(struct typec_altmode *alt, int activate)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(alt);
> > +	u32 header;
> > +
> > +	header = VDO(cpu_to_le16(alt->svid), 1,
> > +		     activate ? CMD_ENTER_MODE : CMD_EXIT_MODE);
> > +	header |= VDO_OPOS(alt->mode);
> > +
> > +	mutex_lock(&port->lock);
> > +	tcpm_queue_vdm(port, header, NULL, 0);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +	mutex_unlock(&port->lock);
> 
> Some of the above functions are port mutex protected, some are not.
> Is this on purpose ?

No. The plan is to always use the mutex.

I can't call typec_altmode_enter/exit() directly from tcpm_pd_svdm()
because the alternate mode drivers may call typec_altmode_enter() from
their probe drivers. I guess the solution is that instead of directly
calling typec_altmode_enter/exit() from tcpm_pm_svdm(), we schedule a
work where we call them. Or would you have some better ideas for this?

For this RFC I just hacked it and didn't use the mutex in
tcpm_altmode_enter/exit().


Thanks for reviewing these,

-- 
heikki

[RFC,v2,3/3] usb: typec: tcpm: Support for Alternate Modes

[Heikki Krogerus]

Hi Guenter,

On Fri, Mar 16, 2018 at 02:32:06PM -0700, Guenter Roeck wrote:
> On Fri, Mar 09, 2018 at 06:19:18PM +0300, Heikki Krogerus wrote:
> > This adds more complete handling of VDMs and registration of
> > partner alternate modes, and introduces callbacks for
> > alternate mode operations.
> > 
> > Only DFP role is supported for now.
> > 
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > ---
> >  drivers/usb/typec/tcpm.c | 133 +++++++++++++++++++++++++++++++++++++++--------
> >  1 file changed, 111 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> > index bfb843ebffa6..34bf5c1f4d81 100644
> > --- a/drivers/usb/typec/tcpm.c
> > +++ b/drivers/usb/typec/tcpm.c
> > @@ -158,13 +158,14 @@ enum pd_msg_request {
> >  /* Alternate mode support */
> >  
> >  #define SVID_DISCOVERY_MAX	16
> > +#define ALTMODE_DISCOVERY_MAX	(SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)
> >  
> >  struct pd_mode_data {
> >  	int svid_index;		/* current SVID index		*/
> >  	int nsvids;
> >  	u16 svids[SVID_DISCOVERY_MAX];
> >  	int altmodes;		/* number of alternate modes	*/
> > -	struct typec_altmode_desc altmode_desc[SVID_DISCOVERY_MAX];
> > +	struct typec_altmode_desc altmode_desc[ALTMODE_DISCOVERY_MAX];
> >  };
> >  
> >  struct tcpm_port {
> > @@ -280,8 +281,8 @@ struct tcpm_port {
> >  	/* Alternate mode data */
> >  
> >  	struct pd_mode_data mode_data;
> > -	struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
> > -	struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
> > +	struct typec_altmode *partner_altmode[ALTMODE_DISCOVERY_MAX];
> > +	struct typec_altmode *port_altmode[ALTMODE_DISCOVERY_MAX];
> >  
> >  	/* Deadline in jiffies to exit src_try_wait state */
> >  	unsigned long max_wait;
> > @@ -985,36 +986,53 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
> >  			 pmdata->altmodes, paltmode->svid,
> >  			 paltmode->mode, paltmode->vdo);
> >  
> > -		port->partner_altmode[pmdata->altmodes] =
> > -			typec_partner_register_altmode(port->partner, paltmode);
> > -		if (!port->partner_altmode[pmdata->altmodes]) {
> > -			tcpm_log(port,
> > -				 "Failed to register modes for SVID 0x%04x",
> > -				 paltmode->svid);
> > -			return;
> > -		}
> >  		pmdata->altmodes++;
> >  	}
> >  }
> >  
> > +static void tcpm_register_partner_altmodes(struct tcpm_port *port)
> > +{
> > +	struct pd_mode_data *modep = &port->mode_data;
> > +	struct typec_altmode *altmode;
> > +	int i;
> > +
> > +	for (i = 0; i < modep->altmodes; i++) {
> > +		altmode = typec_partner_register_altmode(port->partner,
> > +						&modep->altmode_desc[i]);
> > +		if (!altmode)
> > +			tcpm_log(port, "Failed to register partner SVID 0x%04x",
> > +				 modep->altmode_desc[i].svid);
> > +		port->partner_altmode[i] = altmode;
> > +	}
> > +}
> > +
> >  #define supports_modal(port)	PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
> >  
> >  static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> >  			u32 *response)
> >  {
> > -	u32 p0 = le32_to_cpu(payload[0]);
> > -	int cmd_type = PD_VDO_CMDT(p0);
> > -	int cmd = PD_VDO_CMD(p0);
> > +	struct typec_altmode *altmode;
> >  	struct pd_mode_data *modep;
> > +	u32 p[PD_MAX_PAYLOAD];
> >  	int rlen = 0;
> > -	u16 svid;
> > +	int cmd_type;
> > +	int cmd;
> >  	int i;
> >  
> > +	for (i = 0; i < cnt; i++)
> > +		p[i] = le32_to_cpu(payload[i]);
> > +
> > +	cmd_type = PD_VDO_CMDT(p[0]);
> > +	cmd = PD_VDO_CMD(p[0]);
> > +
> >  	tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
> > -		 p0, cmd_type, cmd, cnt);
> > +		 p[0], cmd_type, cmd, cnt);
> >  
> >  	modep = &port->mode_data;
> >  
> > +	altmode = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
> > +				      PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));
> 
> This can return NULL ...
> 
> > +
> >  	switch (cmd_type) {
> >  	case CMDT_INIT:
> >  		switch (cmd) {
> > @@ -1036,17 +1054,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> >  		case CMD_EXIT_MODE:
> >  			break;
> >  		case CMD_ATTENTION:
> > -			break;
> > +			typec_altmode_attention(altmode, p[1]);
> 
> ... and NULL is not handled by typec_altmode_attention().

True.

> > +			return 0;
> >  		default:
> > +			if (typec_altmode_vdm(altmode, p[0], &p[1], cnt) ==
> > +			    VDM_OK)
> 
> typec_altmode_vdm() returns old fashioned error messages.
> Not sure what it is supposed to return, though.

The idea was that the alternate mode driver can inform the port driver
that it not support a specific VDM. In that case we need to NAK.

I'll think about this a bit more.

> > +				return 0;
> >  			break;
> >  		}
> >  		if (rlen >= 1) {
> > -			response[0] = p0 | VDO_CMDT(CMDT_RSP_ACK);
> > +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_ACK);
> >  		} else if (rlen == 0) {
> > -			response[0] = p0 | VDO_CMDT(CMDT_RSP_NAK);
> > +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
> >  			rlen = 1;
> >  		} else {
> > -			response[0] = p0 | VDO_CMDT(CMDT_RSP_BUSY);
> > +			response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
> >  			rlen = 1;
> >  		}
> >  		break;
> > @@ -1079,20 +1101,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> >  			svdm_consume_modes(port, payload, cnt);
> >  			modep->svid_index++;
> >  			if (modep->svid_index < modep->nsvids) {
> > -				svid = modep->svids[modep->svid_index];
> > +				u16 svid = modep->svids[modep->svid_index];
> >  				response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
> >  				rlen = 1;
> >  			} else {
> > -				/* enter alternate mode if/when implemented */
> > +				tcpm_register_partner_altmodes(port);
> >  			}
> >  			break;
> >  		case CMD_ENTER_MODE:
> > +			typec_altmode_enter(altmode);
> 
> typec_altmode_enter() don't handle altmode == NULL.

True. I'll fix that as well.

> No error handling ?
> 
> > +			break;
> > +		case CMD_EXIT_MODE:
> > +			typec_altmode_exit(altmode);
> 
> Doesn't handle NULL. Error handling ?

True, and I'll add error handling for there.

> >  			break;
> >  		default:
> > +			typec_altmode_vdm(altmode, p[0], &p[1], cnt);
> >  			break;
> >  		}
> >  		break;
> >  	default:
> > +		typec_altmode_vdm(altmode, p[0], &p[1], cnt);
> >  		break;
> >  	}
> >  
> > @@ -1352,6 +1380,47 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
> >  	return 0;
> >  }
> >  
> > +static void tcpm_altmode_enter(struct typec_altmode *altmode)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> > +	u32 header;
> > +
> > +	header = VDO(altmode->svid, 1, CMD_ENTER_MODE);
> > +	header |= VDO_OPOS(altmode->mode);
> > +
> > +	tcpm_queue_vdm(port, header, NULL, 0);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +}
> > +
> > +static void tcpm_altmode_exit(struct typec_altmode *altmode)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> > +	u32 header;
> > +
> > +	header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
> > +	header |= VDO_OPOS(altmode->mode);
> > +
> > +	tcpm_queue_vdm(port, header, NULL, 0);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +}
> > +
> > +static int tcpm_altmode_vdm(struct typec_altmode *altmode,
> > +			    u32 header, const u32 *data, int count)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> > +
> > +	tcpm_queue_vdm(port, header, data, count - 1);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct typec_altmode_ops tcpm_altmode_ops = {
> > +	.enter = tcpm_altmode_enter,
> > +	.exit = tcpm_altmode_exit,
> > +	.vdm = tcpm_altmode_vdm,
> > +};
> > +
> >  /*
> >   * PD (data, control) command handling functions
> >   */
> > @@ -3479,6 +3548,23 @@ static void tcpm_init(struct tcpm_port *port)
> >  	tcpm_set_state(port, PORT_RESET, 0);
> >  }
> >  
> > +static int tcpm_activate_mode(struct typec_altmode *alt, int activate)
> > +{
> > +	struct tcpm_port *port = typec_altmode_get_drvdata(alt);
> > +	u32 header;
> > +
> > +	header = VDO(cpu_to_le16(alt->svid), 1,
> > +		     activate ? CMD_ENTER_MODE : CMD_EXIT_MODE);
> > +	header |= VDO_OPOS(alt->mode);
> > +
> > +	mutex_lock(&port->lock);
> > +	tcpm_queue_vdm(port, header, NULL, 0);
> > +	mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> > +	mutex_unlock(&port->lock);
> 
> Some of the above functions are port mutex protected, some are not.
> Is this on purpose ?

No. The plan is to always use the mutex.

I can't call typec_altmode_enter/exit() directly from tcpm_pd_svdm()
because the alternate mode drivers may call typec_altmode_enter() from
their probe drivers. I guess the solution is that instead of directly
calling typec_altmode_enter/exit() from tcpm_pm_svdm(), we schedule a
work where we call them. Or would you have some better ideas for this?

For this RFC I just hacked it and didn't use the mutex in
tcpm_altmode_enter/exit().


Thanks for reviewing these,