[PATCH 0/9] platform/chrome: Type-C switch driver and Type-C framework updates

[PATCH 0/9] platform/chrome: Type-C switch driver and Type-C framework updates

[Prashant Malani]

This series introduces a retimer class to the USB Type-C framework,
It also introduces a Chrome EC (Embedded Controller) switch driver which
registers the aforementioned retimer switches as well as mode-switches.

Patch 1 and 2 introduce the retimer class and associated functions to
the Type-C common code.

Patches 3-7 add the cros-typec-switch driver

Patches 8-9 update cros-ec-typec to get and use retimer switch handles

Submission suggestion (as always, open to better suggestions):
- Patch 1 and 2 can go through the USB repo.
- Patch 3-9 can go through the chrome-platform repo. Since they depend
  on patches 1 and 2, we can create an "topic branch" off of
  usb-next once Patch 1 and 2 are submitted, and then apply Patches 3-9
  on top of that "topic branch" before merging it back into
  chrome-platform's for-next branch

Prashant Malani (9):
  usb: typec: Add support for retimers
  usb: typec: Add retimer handle to port
  platform/chrome: Add Type-C mux set command definitions
  platform/chrome: cros_typec_switch: Add switch driver
  platform/chrome: cros_typec_switch: Set EC retimer
  platform/chrome: cros_typec_switch: Add event check
  platform/chrome: cros_typec_switch: Register mode switches
  platform/chrome: cros_ec_typec: Cleanup switch handle return paths
  platform/chrome: cros_ec_typec: Get retimer handle

 MAINTAINERS                                   |   1 +
 drivers/platform/chrome/Kconfig               |  11 +
 drivers/platform/chrome/Makefile              |   1 +
 drivers/platform/chrome/cros_ec_typec.c       |  50 ++-
 drivers/platform/chrome/cros_typec_switch.c   | 332 ++++++++++++++++++
 drivers/usb/typec/Makefile                    |   2 +-
 drivers/usb/typec/class.c                     |  17 +-
 drivers/usb/typec/class.h                     |   2 +
 drivers/usb/typec/retimer.c                   | 168 +++++++++
 drivers/usb/typec/retimer.h                   |  15 +
 .../linux/platform_data/cros_ec_commands.h    |  18 +
 include/linux/usb/typec_retimer.h             |  45 +++
 12 files changed, 653 insertions(+), 9 deletions(-)
 create mode 100644 drivers/platform/chrome/cros_typec_switch.c
 create mode 100644 drivers/usb/typec/retimer.c
 create mode 100644 drivers/usb/typec/retimer.h
 create mode 100644 include/linux/usb/typec_retimer.h

-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 1/9] usb: typec: Add support for retimers

[Prashant Malani]

Introduce a retimer device class and associated functions that register
and use retimer "switch" devices. These operate in a manner similar to
the "mode-switch" and help configure retimers that exist between the
Type-C connector and host controller(s).

Type C ports can be linked to retimers using firmware node device
references (again, in a manner similar to "mode-switch").

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/usb/typec/Makefile        |   2 +-
 drivers/usb/typec/class.c         |   9 +-
 drivers/usb/typec/class.h         |   1 +
 drivers/usb/typec/retimer.c       | 168 ++++++++++++++++++++++++++++++
 drivers/usb/typec/retimer.h       |  15 +++
 include/linux/usb/typec_retimer.h |  45 ++++++++
 6 files changed, 238 insertions(+), 2 deletions(-)
 create mode 100644 drivers/usb/typec/retimer.c
 create mode 100644 drivers/usb/typec/retimer.h
 create mode 100644 include/linux/usb/typec_retimer.h

diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
index 2f174cd3e5df..4955d9af0811 100644
--- a/drivers/usb/typec/Makefile
+++ b/drivers/usb/typec/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_TYPEC)		+= typec.o
-typec-y				:= class.o mux.o bus.o pd.o
+typec-y				:= class.o mux.o bus.o pd.o retimer.o
 typec-$(CONFIG_ACPI)		+= port-mapper.o
 obj-$(CONFIG_TYPEC)		+= altmodes/
 obj-$(CONFIG_TYPEC_TCPM)	+= tcpm/
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index bbc46b14f99a..2fa0b3718d23 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -2299,10 +2299,14 @@ static int __init typec_init(void)
 	if (ret)
 		goto err_unregister_bus;
 
-	ret = class_register(&typec_class);
+	ret = class_register(&typec_retimer_class);
 	if (ret)
 		goto err_unregister_mux_class;
 
+	ret = class_register(&typec_class);
+	if (ret)
+		goto err_unregister_retimer_class;
+
 	ret = usb_power_delivery_init();
 	if (ret)
 		goto err_unregister_class;
@@ -2312,6 +2316,9 @@ static int __init typec_init(void)
 err_unregister_class:
 	class_unregister(&typec_class);
 
+err_unregister_retimer_class:
+	class_unregister(&typec_retimer_class);
+
 err_unregister_mux_class:
 	class_unregister(&typec_mux_class);
 
diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
index b531f9853bc0..1bb1da124109 100644
--- a/drivers/usb/typec/class.h
+++ b/drivers/usb/typec/class.h
@@ -76,6 +76,7 @@ extern const struct device_type typec_port_dev_type;
 #define is_typec_port(dev) ((dev)->type == &typec_port_dev_type)
 
 extern struct class typec_mux_class;
+extern struct class typec_retimer_class;
 extern struct class typec_class;
 
 #if defined(CONFIG_ACPI)
diff --git a/drivers/usb/typec/retimer.c b/drivers/usb/typec/retimer.c
new file mode 100644
index 000000000000..2fa0aeb9363c
--- /dev/null
+++ b/drivers/usb/typec/retimer.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2022 Google LLC
+ *
+ * USB Type-C Retimer support.
+ * Author: Prashant Malani <pmalani@chromium.org>
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+#include "class.h"
+#include "retimer.h"
+
+static bool dev_name_ends_with(struct device *dev, const char *suffix)
+{
+	const char *name = dev_name(dev);
+	const int name_len = strlen(name);
+	const int suffix_len = strlen(suffix);
+
+	if (suffix_len > name_len)
+		return false;
+
+	return strcmp(name + (name_len - suffix_len), suffix) == 0;
+}
+
+static int retimer_fwnode_match(struct device *dev, const void *fwnode)
+{
+	return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-retimer");
+}
+
+static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data)
+{
+	struct device *dev  = class_find_device(&typec_retimer_class, NULL, fwnode,
+						retimer_fwnode_match);
+
+	return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER);
+}
+
+/**
+ * fwnode_typec_retimer_get - Find USB Type-C retimer.
+ * @fwnode: The caller device node.
+ *
+ * Finds a retimer linked to the caller. This function is primarily meant for the
+ * Type-C drivers. Returns a reference to the retimer on success, NULL if no
+ * matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection
+ * was found but the retimer has not been enumerated yet.
+ */
+struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode)
+{
+	struct typec_retimer *retimer;
+
+	retimer = fwnode_connection_find_match(fwnode, "retimer-switch", NULL, typec_retimer_match);
+	if (!IS_ERR_OR_NULL(retimer))
+		WARN_ON(!try_module_get(retimer->dev.parent->driver->owner));
+
+	return retimer;
+}
+EXPORT_SYMBOL_GPL(fwnode_typec_retimer_get);
+
+/**
+ * typec_retimer_put - Release handle to a retimer.
+ * @retimer: USB Type-C Connector Retimer.
+ *
+ * Decrements reference count for @retimer.
+ */
+void typec_retimer_put(struct typec_retimer *retimer)
+{
+	if (!IS_ERR_OR_NULL(retimer)) {
+		module_put(retimer->dev.parent->driver->owner);
+		put_device(&retimer->dev);
+	}
+}
+EXPORT_SYMBOL_GPL(typec_retimer_put);
+
+int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
+{
+	if (IS_ERR_OR_NULL(retimer))
+		return 0;
+
+	return retimer->set(retimer, state);
+}
+EXPORT_SYMBOL_GPL(typec_retimer_set);
+
+static void typec_retimer_release(struct device *dev)
+{
+	kfree(to_typec_retimer(dev));
+}
+
+static const struct device_type typec_retimer_dev_type = {
+	.name = "retimer_switch",
+	.release = typec_retimer_release,
+};
+
+/**
+ * typec_retimer_register - Register a retimer device.
+ * @parent: Parent device.
+ * @desc: Retimer description.
+ *
+ * Some USB Type-C connectors have their physical lines routed through retimers before they
+ * reach muxes or host controllers. In some cases (for example: using alternate modes)
+ * these retimers need to be reconfigured appropriately. This function registers retimer
+ * switches which route and potentially modify the signals on the Type C physical lines
+ * enroute to the host controllers.
+ */
+struct typec_retimer *
+typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc)
+{
+	struct typec_retimer *retimer;
+	int ret;
+
+	if (!desc || !desc->set)
+		return ERR_PTR(-EINVAL);
+
+	retimer = kzalloc(sizeof(*retimer), GFP_KERNEL);
+	if (!retimer)
+		return ERR_PTR(-ENOMEM);
+
+	retimer->set = desc->set;
+
+	device_initialize(&retimer->dev);
+	retimer->dev.parent = parent;
+	retimer->dev.fwnode = desc->fwnode;
+	retimer->dev.class = &typec_retimer_class;
+	retimer->dev.type = &typec_retimer_dev_type;
+	retimer->dev.driver_data = desc->drvdata;
+	dev_set_name(&retimer->dev, "%s-retimer",
+		     desc->name ? desc->name : dev_name(parent));
+
+	ret = device_add(&retimer->dev);
+	if (ret) {
+		dev_err(parent, "failed to register retimer (%d)\n", ret);
+		put_device(&retimer->dev);
+		return ERR_PTR(ret);
+	}
+
+	return retimer;
+}
+EXPORT_SYMBOL_GPL(typec_retimer_register);
+
+/**
+ * typec_retimer_unregister - Unregister retimer device.
+ * @retimer: USB Type-C Connector retimer.
+ *
+ * Unregister retimer that was registered with typec_retimer_register().
+ */
+void typec_retimer_unregister(struct typec_retimer *retimer)
+{
+	if (!IS_ERR_OR_NULL(retimer))
+		device_unregister(&retimer->dev);
+}
+EXPORT_SYMBOL_GPL(typec_retimer_unregister);
+
+void *typec_retimer_get_drvdata(struct typec_retimer *retimer)
+{
+	return dev_get_drvdata(&retimer->dev);
+}
+EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata);
+
+struct class typec_retimer_class = {
+	.name = "typec_retimer",
+	.owner = THIS_MODULE,
+};
diff --git a/drivers/usb/typec/retimer.h b/drivers/usb/typec/retimer.h
new file mode 100644
index 000000000000..fa15951d4846
--- /dev/null
+++ b/drivers/usb/typec/retimer.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __USB_TYPEC_RETIMER__
+#define __USB_TYPEC_RETIMER__
+
+#include <linux/usb/typec_retimer.h>
+
+struct typec_retimer {
+	struct device dev;
+	typec_retimer_set_fn_t set;
+};
+
+#define to_typec_retimer(_dev_) container_of(_dev_, struct typec_retimer, dev)
+
+#endif /* __USB_TYPEC_RETIMER__ */
diff --git a/include/linux/usb/typec_retimer.h b/include/linux/usb/typec_retimer.h
new file mode 100644
index 000000000000..5e036b3360e2
--- /dev/null
+++ b/include/linux/usb/typec_retimer.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __USB_TYPEC_RETIMER
+#define __USB_TYPEC_RETIMER
+
+#include <linux/property.h>
+#include <linux/usb/typec.h>
+
+struct device;
+struct typec_retimer;
+struct typec_altmode;
+struct fwnode_handle;
+
+struct typec_retimer_state {
+	struct typec_altmode *alt;
+	unsigned long mode;
+	void *data;
+};
+
+typedef int (*typec_retimer_set_fn_t)(struct typec_retimer *retimer,
+				      struct typec_retimer_state *state);
+
+struct typec_retimer_desc {
+	struct fwnode_handle *fwnode;
+	typec_retimer_set_fn_t set;
+	const char *name;
+	void *drvdata;
+};
+
+struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode);
+void typec_retimer_put(struct typec_retimer *retimer);
+int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state);
+
+static inline struct typec_retimer *typec_retimer_get(struct device *dev)
+{
+	return fwnode_typec_retimer_get(dev_fwnode(dev));
+}
+
+struct typec_retimer *
+typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc);
+void typec_retimer_unregister(struct typec_retimer *retimer);
+
+void *typec_retimer_get_drvdata(struct typec_retimer *retimer);
+
+#endif /* __USB_TYPEC_RETIMER */
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 2/9] usb: typec: Add retimer handle to port

[Prashant Malani]

Similar to mux and orientation switch, add a handle for registered
retimer to the port, so that it has handles to the various switches
connected to it.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/usb/typec/class.c | 8 ++++++++
 drivers/usb/typec/class.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 2fa0b3718d23..2bc5fbdb25dd 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/usb/pd_vdo.h>
 #include <linux/usb/typec_mux.h>
+#include <linux/usb/typec_retimer.h>
 
 #include "bus.h"
 #include "class.h"
@@ -2249,6 +2250,13 @@ struct typec_port *typec_register_port(struct device *parent,
 		return ERR_PTR(ret);
 	}
 
+	port->retimer = typec_retimer_get(&port->dev);
+	if (IS_ERR(port->retimer)) {
+		ret = PTR_ERR(port->retimer);
+		put_device(&port->dev);
+		return ERR_PTR(ret);
+	}
+
 	ret = device_add(&port->dev);
 	if (ret) {
 		dev_err(parent, "failed to register port (%d)\n", ret);
diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
index 1bb1da124109..97520406929e 100644
--- a/drivers/usb/typec/class.h
+++ b/drivers/usb/typec/class.h
@@ -55,6 +55,7 @@ struct typec_port {
 	enum typec_orientation		orientation;
 	struct typec_switch		*sw;
 	struct typec_mux		*mux;
+	struct typec_retimer		*retimer;
 
 	const struct typec_capability	*cap;
 	const struct typec_operations   *ops;
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 3/9] platform/chrome: Add Type-C mux set command definitions

[Prashant Malani]

Copy EC header definitions for the USB Type-C Mux control command from
the EC code base. Also pull in "TBT_UFP_REPLY" definitions, since that
is the prior entry in the enum.

These headers are already present in the EC code base. [1]

[1] https://chromium.googlesource.com/chromiumos/platform/ec/+/b80f85a94a423273c1638ef7b662c56931a138dd/include/ec_commands.h

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 include/linux/platform_data/cros_ec_commands.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h
index 8cfa8cfca77e..a3945c5e7f50 100644
--- a/include/linux/platform_data/cros_ec_commands.h
+++ b/include/linux/platform_data/cros_ec_commands.h
@@ -5722,8 +5722,21 @@ enum typec_control_command {
 	TYPEC_CONTROL_COMMAND_EXIT_MODES,
 	TYPEC_CONTROL_COMMAND_CLEAR_EVENTS,
 	TYPEC_CONTROL_COMMAND_ENTER_MODE,
+	TYPEC_CONTROL_COMMAND_TBT_UFP_REPLY,
+	TYPEC_CONTROL_COMMAND_USB_MUX_SET,
 };
 
+/* Replies the AP may specify to the TBT EnterMode command as a UFP */
+enum typec_tbt_ufp_reply {
+	TYPEC_TBT_UFP_REPLY_NAK,
+	TYPEC_TBT_UFP_REPLY_ACK,
+};
+
+struct typec_usb_mux_set {
+	uint8_t mux_index;	/* Index of the mux to set in the chain */
+	uint8_t mux_flags;	/* USB_PD_MUX_*-encoded USB mux state to set */
+} __ec_align1;
+
 struct ec_params_typec_control {
 	uint8_t port;
 	uint8_t command;	/* enum typec_control_command */
@@ -5737,6 +5750,8 @@ struct ec_params_typec_control {
 	union {
 		uint32_t clear_events_mask;
 		uint8_t mode_to_enter;      /* enum typec_mode */
+		uint8_t tbt_ufp_reply;      /* enum typec_tbt_ufp_reply */
+		struct typec_usb_mux_set mux_params;
 		uint8_t placeholder[128];
 	};
 } __ec_align1;
@@ -5815,6 +5830,9 @@ enum tcpc_cc_polarity {
 #define PD_STATUS_EVENT_SOP_DISC_DONE		BIT(0)
 #define PD_STATUS_EVENT_SOP_PRIME_DISC_DONE	BIT(1)
 #define PD_STATUS_EVENT_HARD_RESET		BIT(2)
+#define PD_STATUS_EVENT_DISCONNECTED		BIT(3)
+#define PD_STATUS_EVENT_MUX_0_SET_DONE		BIT(4)
+#define PD_STATUS_EVENT_MUX_1_SET_DONE		BIT(5)
 
 struct ec_params_typec_status {
 	uint8_t port;
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 4/9] platform/chrome: cros_typec_switch: Add switch driver

[Prashant Malani]

Introduce a driver to configure USB Type-C mode switches and retimers
which are controlled by the Chrome OS EC (Embedded Controller).
This allows Type-C port drivers, as well as alternate mode drivers to
configure their relevant mode switches and retimers according to the
Type-C state they want to achieve.

ACPI devices with ID GOOG001A will bind to this driver.

Currently, we only register a retimer switch with a stub set function.
Subsequent patches will implement the host command set functionality,
and introduce mode switches.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 MAINTAINERS                                 |   1 +
 drivers/platform/chrome/Kconfig             |  11 ++
 drivers/platform/chrome/Makefile            |   1 +
 drivers/platform/chrome/cros_typec_switch.c | 171 ++++++++++++++++++++
 4 files changed, 184 insertions(+)
 create mode 100644 drivers/platform/chrome/cros_typec_switch.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 7533cb27adc0..35ea91c619b7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4752,6 +4752,7 @@ M:	Prashant Malani <pmalani@chromium.org>
 L:	chrome-platform@lists.linux.dev
 S:	Maintained
 F:	drivers/platform/chrome/cros_ec_typec.c
+F:	drivers/platform/chrome/cros_typec_switch.c
 
 CHROMEOS EC USB PD NOTIFY DRIVER
 M:	Prashant Malani <pmalani@chromium.org>
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 717299cbccac..c62a514a087f 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -265,6 +265,17 @@ config CHROMEOS_PRIVACY_SCREEN
 	  this should probably always be built into the kernel to avoid or
 	  minimize drm probe deferral.
 
+config CROS_TYPEC_SWITCH
+	tristate "ChromeOS EC Type-C Switch Control"
+	depends on MFD_CROS_EC_DEV && TYPEC
+	default MFD_CROS_EC_DEV
+	help
+	  If you say Y here, you get support for configuring the Chrome OS EC Type C
+	  muxes and retimers.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called cros_typec_switch.
+
 source "drivers/platform/chrome/wilco_ec/Kconfig"
 
 endif # CHROMEOS_PLATFORMS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 52f5a2dde8b8..0dcaf6a7ed27 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_CHROMEOS_TBMC)		+= chromeos_tbmc.o
 obj-$(CONFIG_CROS_EC)			+= cros_ec.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
 obj-$(CONFIG_CROS_EC_ISHTP)		+= cros_ec_ishtp.o
+obj-$(CONFIG_CROS_TYPEC_SWITCH)		+= cros_typec_switch.o
 obj-$(CONFIG_CROS_EC_RPMSG)		+= cros_ec_rpmsg.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
 cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_mec.o
diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
new file mode 100644
index 000000000000..1a795f613543
--- /dev/null
+++ b/drivers/platform/chrome/cros_typec_switch.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022 Google LLC
+ *
+ * This driver provides the ability to configure Type C muxes and retimers which are controlled by
+ * the Chrome OS EC.
+ */
+
+#include <linux/acpi.h>
+#include <linux/module.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_device.h>
+#include <linux/usb/typec_retimer.h>
+
+#define DRV_NAME "cros-typec-switch"
+
+/* Handles and other relevant data required for each port's switches. */
+struct cros_typec_port {
+	int port_num;
+	struct typec_retimer *retimer;
+	struct cros_typec_switch_data *sdata;
+};
+
+/* Driver-specific data. */
+struct cros_typec_switch_data {
+	struct device *dev;
+	struct cros_ec_device *ec;
+	struct cros_typec_port *ports[EC_USB_PD_MAX_PORTS];
+};
+
+static int
+cros_typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
+{
+	return 0;
+}
+
+void cros_typec_unregister_switches(struct cros_typec_switch_data *sdata)
+{
+	int i;
+
+	for (i = 0; i < EC_USB_PD_MAX_PORTS; i++) {
+		if (!sdata->ports[i])
+			continue;
+		typec_retimer_unregister(sdata->ports[i]->retimer);
+	}
+}
+
+int cros_typec_register_retimer(struct cros_typec_port *port, struct fwnode_handle *fwnode)
+{
+	struct typec_retimer_desc retimer_desc = {
+		.fwnode = fwnode,
+		.drvdata = port,
+		.name = fwnode_get_name(fwnode),
+		.set = cros_typec_retimer_set,
+	};
+
+	port->retimer = typec_retimer_register(port->sdata->dev, &retimer_desc);
+	if (IS_ERR(port->retimer))
+		return PTR_ERR(port->retimer);
+
+	return 0;
+}
+
+static int cros_typec_register_switches(struct cros_typec_switch_data *sdata)
+{
+	struct cros_typec_port *port = NULL;
+	struct device *dev = sdata->dev;
+	struct fwnode_handle *fwnode;
+	struct acpi_device *adev;
+	unsigned long long index;
+	int ret = 0;
+	int nports;
+
+	nports = device_get_child_node_count(dev);
+	if (nports == 0) {
+		dev_err(dev, "No switch devices found.\n");
+		return -ENODEV;
+	}
+
+	device_for_each_child_node(dev, fwnode) {
+		port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+		if (!port) {
+			ret = -ENOMEM;
+			goto err_switch;
+		}
+
+		adev = to_acpi_device_node(fwnode);
+		if (!adev) {
+			dev_err(fwnode->dev, "Couldn't get ACPI device handle\n");
+			ret = -ENODEV;
+			goto err_switch;
+		}
+
+		ret = acpi_evaluate_integer(adev->handle, "_ADR", NULL, &index);
+		if (ACPI_FAILURE(ret)) {
+			dev_err(fwnode->dev, "_ADR wasn't evaluated\n");
+			ret = -ENODATA;
+			goto err_switch;
+		}
+
+		if (index < 0 || index >= EC_USB_PD_MAX_PORTS) {
+			dev_err(fwnode->dev, "Invalid port index number: %llu", index);
+			ret = -EINVAL;
+			goto err_switch;
+		}
+		port->sdata = sdata;
+		port->port_num = index;
+		sdata->ports[index] = port;
+
+		ret = cros_typec_register_retimer(port, fwnode);
+		if (ret) {
+			dev_err(dev, "Retimer switch register failed\n");
+			goto err_switch;
+		}
+
+		dev_dbg(dev, "Retimer switch registered for index %llu\n", index);
+	}
+
+	return 0;
+err_switch:
+	cros_typec_unregister_switches(sdata);
+	return ret;
+}
+
+static int cros_typec_switch_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cros_typec_switch_data *sdata;
+
+	sdata = devm_kzalloc(dev, sizeof(*sdata), GFP_KERNEL);
+	if (!sdata)
+		return -ENOMEM;
+
+	sdata->dev = dev;
+	sdata->ec = dev_get_drvdata(pdev->dev.parent);
+
+	platform_set_drvdata(pdev, sdata);
+
+	return cros_typec_register_switches(sdata);
+}
+
+static int cros_typec_switch_remove(struct platform_device *pdev)
+{
+	struct cros_typec_switch_data *sdata = platform_get_drvdata(pdev);
+
+	cros_typec_unregister_switches(sdata);
+	return 0;
+}
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id cros_typec_switch_acpi_id[] = {
+	{ "GOOG001A", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, cros_typec_switch_acpi_id);
+#endif
+
+static struct platform_driver cros_typec_switch_driver = {
+	.driver	= {
+		.name = DRV_NAME,
+		.acpi_match_table = ACPI_PTR(cros_typec_switch_acpi_id),
+	},
+	.probe = cros_typec_switch_probe,
+	.remove = cros_typec_switch_remove,
+};
+
+module_platform_driver(cros_typec_switch_driver);
+
+MODULE_AUTHOR("Prashant Malani <pmalani@chromium.org>");
+MODULE_DESCRIPTION("Chrome OS EC Type C Switch control");
+MODULE_LICENSE("GPL");
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 5/9] platform/chrome: cros_typec_switch: Set EC retimer

[Prashant Malani]

Invoke Chrome EC host commands to set EC-controlled retimer switches to
the state the Type-C framework instructs.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/platform/chrome/cros_typec_switch.c | 56 ++++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
index 1a795f613543..9faa442dd81a 100644
--- a/drivers/platform/chrome/cros_typec_switch.c
+++ b/drivers/platform/chrome/cros_typec_switch.c
@@ -9,7 +9,10 @@
 #include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
 #include <linux/platform_device.h>
+#include <linux/usb/typec_altmode.h>
+#include <linux/usb/typec_dp.h>
 #include <linux/usb/typec_retimer.h>
 
 #define DRV_NAME "cros-typec-switch"
@@ -28,10 +31,61 @@ struct cros_typec_switch_data {
 	struct cros_typec_port *ports[EC_USB_PD_MAX_PORTS];
 };
 
+static int cros_typec_cmd_mux_set(struct cros_typec_switch_data *sdata, int port_num, u8 index,
+				  u8 state)
+{
+	struct typec_usb_mux_set params = {
+		.mux_index = index,
+		.mux_flags = state,
+	};
+
+	struct ec_params_typec_control req = {
+		.port = port_num,
+		.command = TYPEC_CONTROL_COMMAND_USB_MUX_SET,
+		.mux_params = params,
+	};
+
+	return cros_ec_command(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req,
+			       sizeof(req), NULL, 0);
+}
+
+static int cros_typec_get_mux_state(unsigned long mode, struct typec_altmode *alt)
+{
+	int ret = -EOPNOTSUPP;
+
+	if (mode == TYPEC_STATE_SAFE)
+		ret = USB_PD_MUX_SAFE_MODE;
+	else if (mode == TYPEC_STATE_USB)
+		ret = USB_PD_MUX_USB_ENABLED;
+	else if (alt && alt->svid == USB_TYPEC_DP_SID)
+		ret = USB_PD_MUX_DP_ENABLED;
+
+	return ret;
+}
+
+/*
+ * The Chrome EC treats both mode-switches and retimers as "muxes" for the purposes of the
+ * host command API. This common function configures and verifies the retimer/mode-switch
+ * according to the provided setting.
+ */
+static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int port_num, int index,
+				    unsigned long mode, struct typec_altmode *alt)
+{
+	int ret = cros_typec_get_mux_state(mode, alt);
+
+	if (ret < 0)
+		return ret;
+
+	return cros_typec_cmd_mux_set(sdata, port_num, index, (u8)ret);
+}
+
 static int
 cros_typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
 {
-	return 0;
+	struct cros_typec_port *port = typec_retimer_get_drvdata(retimer);
+
+	/* Retimers have index 1. */
+	return cros_typec_configure_mux(port->sdata, port->port_num, 1, state->mode, state->alt);
 }
 
 void cros_typec_unregister_switches(struct cros_typec_switch_data *sdata)
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 6/9] platform/chrome: cros_typec_switch: Add event check

[Prashant Malani]

The Chrome EC updates Type-C status events when mux set requests from
the Application Processor (AP) are completed. Add a check to the
flow of configuring muxes to look for this status done bit, so that
the driver is aware that the mux set completed successfully or not.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/platform/chrome/cros_typec_switch.c | 72 ++++++++++++++++++++-
 1 file changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
index 9faa442dd81a..a226f828514f 100644
--- a/drivers/platform/chrome/cros_typec_switch.c
+++ b/drivers/platform/chrome/cros_typec_switch.c
@@ -7,6 +7,8 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/module.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
@@ -63,6 +65,40 @@ static int cros_typec_get_mux_state(unsigned long mode, struct typec_altmode *al
 	return ret;
 }
 
+static int cros_typec_send_clear_event(struct cros_typec_switch_data *sdata, int port_num,
+				       u32 events_mask)
+{
+	struct ec_params_typec_control req = {
+		.port = port_num,
+		.command = TYPEC_CONTROL_COMMAND_CLEAR_EVENTS,
+		.clear_events_mask = events_mask,
+	};
+
+	return cros_ec_command(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req,
+			       sizeof(req), NULL, 0);
+}
+
+bool cros_typec_check_event(struct cros_typec_switch_data *sdata, int port_num, u32 mask)
+{
+	struct ec_response_typec_status resp;
+	struct ec_params_typec_status req = {
+		.port = port_num,
+	};
+	int ret;
+
+	ret = cros_ec_command(sdata->ec, 0, EC_CMD_TYPEC_STATUS, &req, sizeof(req),
+			      &resp, sizeof(resp));
+	if (ret < 0) {
+		dev_warn(sdata->dev, "EC_CMD_TYPEC_STATUS failed for port: %d\n", port_num);
+		return false;
+	}
+
+	if (resp.events & mask)
+		return true;
+
+	return false;
+}
+
 /*
  * The Chrome EC treats both mode-switches and retimers as "muxes" for the purposes of the
  * host command API. This common function configures and verifies the retimer/mode-switch
@@ -71,12 +107,44 @@ static int cros_typec_get_mux_state(unsigned long mode, struct typec_altmode *al
 static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int port_num, int index,
 				    unsigned long mode, struct typec_altmode *alt)
 {
-	int ret = cros_typec_get_mux_state(mode, alt);
+	unsigned long end;
+	u32 event_mask;
+	u8 mux_state;
+	int ret;
+
+	ret = cros_typec_get_mux_state(mode, alt);
+	if (ret < 0)
+		return ret;
+	mux_state = (u8)ret;
 
+	/* Clear any old mux set done event. */
+	if (index == 0)
+		event_mask = PD_STATUS_EVENT_MUX_0_SET_DONE;
+	else
+		event_mask = PD_STATUS_EVENT_MUX_1_SET_DONE;
+
+	ret = cros_typec_send_clear_event(sdata, port_num, event_mask);
+	if (ret < 0)
+		return ret;
+
+	/* Send the set command. */
+	ret = cros_typec_cmd_mux_set(sdata, port_num, index, mux_state);
 	if (ret < 0)
 		return ret;
 
-	return cros_typec_cmd_mux_set(sdata, port_num, index, (u8)ret);
+	/* Check for the mux set done event. */
+	end = jiffies + msecs_to_jiffies(1000);
+	do {
+		if (cros_typec_check_event(sdata, port_num, event_mask))
+			return 0;
+
+		usleep_range(500, 1000);
+	} while (time_before(jiffies, end));
+
+	dev_err(sdata->dev, "Timed out waiting for mux set done on index: %d, state: %d\n",
+		index, mux_state);
+
+	return -ETIMEDOUT;
 }
 
 static int
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 7/9] platform/chrome: cros_typec_switch: Register mode switches

[Prashant Malani]

Register mode switch devices for Type C connectors, when they are
specified by firmware. These control Type C configuration for any USB
Type-C mode switches (sometimes known as "muxes") which are controlled
by the Chrome EC.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/platform/chrome/cros_typec_switch.c | 39 +++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
index a226f828514f..2ea42e6596b9 100644
--- a/drivers/platform/chrome/cros_typec_switch.c
+++ b/drivers/platform/chrome/cros_typec_switch.c
@@ -15,6 +15,7 @@
 #include <linux/platform_device.h>
 #include <linux/usb/typec_altmode.h>
 #include <linux/usb/typec_dp.h>
+#include <linux/usb/typec_mux.h>
 #include <linux/usb/typec_retimer.h>
 
 #define DRV_NAME "cros-typec-switch"
@@ -22,6 +23,7 @@
 /* Handles and other relevant data required for each port's switches. */
 struct cros_typec_port {
 	int port_num;
+	struct typec_mux_dev *mode_switch;
 	struct typec_retimer *retimer;
 	struct cros_typec_switch_data *sdata;
 };
@@ -147,6 +149,15 @@ static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int po
 	return -ETIMEDOUT;
 }
 
+static int
+cros_typec_mode_switch_set(struct typec_mux_dev *mode_switch, struct typec_mux_state *state)
+{
+	struct cros_typec_port *port = typec_mux_get_drvdata(mode_switch);
+
+	/* Mode switches have index 0. */
+	return cros_typec_configure_mux(port->sdata, port->port_num, 0, state->mode, state->alt);
+}
+
 static int
 cros_typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
 {
@@ -164,9 +175,26 @@ void cros_typec_unregister_switches(struct cros_typec_switch_data *sdata)
 		if (!sdata->ports[i])
 			continue;
 		typec_retimer_unregister(sdata->ports[i]->retimer);
+		typec_mux_unregister(sdata->ports[i]->mode_switch);
 	}
 }
 
+int cros_typec_register_mode_switch(struct cros_typec_port *port, struct fwnode_handle *fwnode)
+{
+	struct typec_mux_desc mode_switch_desc = {
+		.fwnode = fwnode,
+		.drvdata = port,
+		.name = fwnode_get_name(fwnode),
+		.set = cros_typec_mode_switch_set,
+	};
+
+	port->mode_switch = typec_mux_register(port->sdata->dev, &mode_switch_desc);
+	if (IS_ERR(port->mode_switch))
+		return PTR_ERR(port->mode_switch);
+
+	return 0;
+}
+
 int cros_typec_register_retimer(struct cros_typec_port *port, struct fwnode_handle *fwnode)
 {
 	struct typec_retimer_desc retimer_desc = {
@@ -236,6 +264,17 @@ static int cros_typec_register_switches(struct cros_typec_switch_data *sdata)
 		}
 
 		dev_dbg(dev, "Retimer switch registered for index %llu\n", index);
+
+		if (!fwnode_property_read_bool(fwnode, "mode-switch"))
+			continue;
+
+		ret = cros_typec_register_mode_switch(port, fwnode);
+		if (ret) {
+			dev_err(dev, "Mode switch register failed\n");
+			goto err_switch;
+		}
+
+		dev_dbg(dev, "Mode switch registered for index %llu\n", index);
 	}
 
 	return 0;
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 8/9] platform/chrome: cros_ec_typec: Cleanup switch handle return paths

[Prashant Malani]

Some of the return paths for the cros_typec_get_switch_handles()
aren't necessary. Clean up the return paths to only undo the handle
get's which succeeded.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/platform/chrome/cros_ec_typec.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index 7cb2e35c4ded..39e6fd4491a9 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -157,12 +157,10 @@ static int cros_typec_get_switch_handles(struct cros_typec_port *port,
 	return 0;
 
 role_sw_err:
-	usb_role_switch_put(port->role_sw);
-ori_sw_err:
 	typec_switch_put(port->ori_sw);
-mux_err:
+ori_sw_err:
 	typec_mux_put(port->mux);
-
+mux_err:
 	return -ENODEV;
 }
 
-- 
2.37.0.rc0.161.g10f37bed90-goog

[PATCH 9/9] platform/chrome: cros_ec_typec: Get retimer handle

[Prashant Malani]

Where available, obtain the handle to retimer switch specified via
firmware, and update the mux configuration callsites to add retimer
support for supported modes.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
---
 drivers/platform/chrome/cros_ec_typec.c | 44 +++++++++++++++++++++++--
 1 file changed, 41 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index 39e6fd4491a9..38c4ac754ea9 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -20,6 +20,7 @@
 #include <linux/usb/typec_altmode.h>
 #include <linux/usb/typec_dp.h>
 #include <linux/usb/typec_mux.h>
+#include <linux/usb/typec_retimer.h>
 #include <linux/usb/typec_tbt.h>
 #include <linux/usb/role.h>
 
@@ -53,6 +54,7 @@ struct cros_typec_port {
 	struct usb_pd_identity c_identity;
 	struct typec_switch *ori_sw;
 	struct typec_mux *mux;
+	struct typec_retimer *retimer;
 	struct usb_role_switch *role_sw;
 
 	/* Variables keeping track of switch state. */
@@ -142,6 +144,12 @@ static int cros_typec_get_switch_handles(struct cros_typec_port *port,
 		goto mux_err;
 	}
 
+	port->retimer = fwnode_typec_retimer_get(fwnode);
+	if (IS_ERR(port->retimer)) {
+		dev_dbg(dev, "Retimer handle not found.\n");
+		goto retimer_sw_err;
+	}
+
 	port->ori_sw = fwnode_typec_switch_get(fwnode);
 	if (IS_ERR(port->ori_sw)) {
 		dev_dbg(dev, "Orientation switch handle not found.\n");
@@ -159,6 +167,8 @@ static int cros_typec_get_switch_handles(struct cros_typec_port *port,
 role_sw_err:
 	typec_switch_put(port->ori_sw);
 ori_sw_err:
+	typec_retimer_put(port->retimer);
+retimer_sw_err:
 	typec_mux_put(port->mux);
 mux_err:
 	return -ENODEV;
@@ -203,6 +213,21 @@ static void cros_typec_unregister_altmodes(struct cros_typec_data *typec, int po
 	}
 }
 
+/*
+ * Map the Type-C Mux state to retimer state and call the retimer set function. We need this
+ * because we re-use the Type-C mux state for retimers.
+ */
+static int cros_typec_retimer_set(struct typec_retimer  *retimer, struct typec_mux_state state)
+{
+	struct typec_retimer_state rstate = {
+		.alt = state.alt,
+		.mode = state.mode,
+		.data = state.data,
+	};
+
+	return typec_retimer_set(retimer, &rstate);
+}
+
 static int cros_typec_usb_disconnect_state(struct cros_typec_port *port)
 {
 	port->state.alt = NULL;
@@ -211,6 +236,7 @@ static int cros_typec_usb_disconnect_state(struct cros_typec_port *port)
 
 	usb_role_switch_set_role(port->role_sw, USB_ROLE_NONE);
 	typec_switch_set(port->ori_sw, TYPEC_ORIENTATION_NONE);
+	cros_typec_retimer_set(port->retimer, port->state);
 
 	return typec_mux_set(port->mux, &port->state);
 }
@@ -381,9 +407,14 @@ static int cros_typec_init_ports(struct cros_typec_data *typec)
 
 static int cros_typec_usb_safe_state(struct cros_typec_port *port)
 {
+	int ret;
 	port->state.mode = TYPEC_STATE_SAFE;
 
-	return typec_mux_set(port->mux, &port->state);
+	ret = cros_typec_retimer_set(port->retimer, port->state);
+	if (!ret)
+		ret = typec_mux_set(port->mux, &port->state);
+
+	return ret;
 }
 
 /*
@@ -480,7 +511,11 @@ static int cros_typec_enable_dp(struct cros_typec_data *typec,
 	port->state.data = &dp_data;
 	port->state.mode = TYPEC_MODAL_STATE(ffs(pd_ctrl->dp_mode));
 
-	return typec_mux_set(port->mux, &port->state);
+	ret = cros_typec_retimer_set(port->retimer, port->state);
+	if (!ret)
+		ret = typec_mux_set(port->mux, &port->state);
+
+	return ret;
 }
 
 static int cros_typec_enable_usb4(struct cros_typec_data *typec,
@@ -569,7 +604,10 @@ static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
 	} else if (port->mux_flags & USB_PD_MUX_USB_ENABLED) {
 		port->state.alt = NULL;
 		port->state.mode = TYPEC_STATE_USB;
-		ret = typec_mux_set(port->mux, &port->state);
+
+		ret = cros_typec_retimer_set(port->retimer, port->state);
+		if (!ret)
+			ret = typec_mux_set(port->mux, &port->state);
 	} else {
 		dev_dbg(typec->dev,
 			"Unrecognized mode requested, mux flags: %x\n",
-- 
2.37.0.rc0.161.g10f37bed90-goog

Re: [PATCH 1/9] usb: typec: Add support for retimers

[Heikki Krogerus]

On Wed, Jun 29, 2022 at 11:32:19PM +0000, Prashant Malani wrote:
> Introduce a retimer device class and associated functions that register
> and use retimer "switch" devices. These operate in a manner similar to
> the "mode-switch" and help configure retimers that exist between the
> Type-C connector and host controller(s).
> 
> Type C ports can be linked to retimers using firmware node device
> references (again, in a manner similar to "mode-switch").
> 
> Signed-off-by: Prashant Malani <pmalani@chromium.org>

Cool! This looks really good to me.

I'll add Mika here, just to keep him in the loop. Thunderbolt/USB4 can
control the same physical retimers over the SBU line. Right now there
is no conflict, but I think we want to later be able to use these
devices to upgrade the retimer firmware, and that is something that
the Thunderbolt/USB4 already does. So let's keep an eye on this.

I wonder, would it make sense to later make the thunderbolt_retimer
devices also part of the device class that's introduced here? I think
that way it would be easier to later figure out which
thunderbolt_retimer and which retimer_switch represent the same
physical retimer. And perhaps it would also be more clear for the user
space to have a single device class for the retimers?

Maybe the device class could be named just "retimer", and the device
type could then be named "typec_retimer" instead of "retimer_switch"?

thanks,

> ---
>  drivers/usb/typec/Makefile        |   2 +-
>  drivers/usb/typec/class.c         |   9 +-
>  drivers/usb/typec/class.h         |   1 +
>  drivers/usb/typec/retimer.c       | 168 ++++++++++++++++++++++++++++++
>  drivers/usb/typec/retimer.h       |  15 +++
>  include/linux/usb/typec_retimer.h |  45 ++++++++
>  6 files changed, 238 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/usb/typec/retimer.c
>  create mode 100644 drivers/usb/typec/retimer.h
>  create mode 100644 include/linux/usb/typec_retimer.h
> 
> diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
> index 2f174cd3e5df..4955d9af0811 100644
> --- a/drivers/usb/typec/Makefile
> +++ b/drivers/usb/typec/Makefile
> @@ -1,6 +1,6 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_TYPEC)		+= typec.o
> -typec-y				:= class.o mux.o bus.o pd.o
> +typec-y				:= class.o mux.o bus.o pd.o retimer.o
>  typec-$(CONFIG_ACPI)		+= port-mapper.o
>  obj-$(CONFIG_TYPEC)		+= altmodes/
>  obj-$(CONFIG_TYPEC_TCPM)	+= tcpm/
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index bbc46b14f99a..2fa0b3718d23 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -2299,10 +2299,14 @@ static int __init typec_init(void)
>  	if (ret)
>  		goto err_unregister_bus;
>  
> -	ret = class_register(&typec_class);
> +	ret = class_register(&typec_retimer_class);
>  	if (ret)
>  		goto err_unregister_mux_class;
>  
> +	ret = class_register(&typec_class);
> +	if (ret)
> +		goto err_unregister_retimer_class;
> +
>  	ret = usb_power_delivery_init();
>  	if (ret)
>  		goto err_unregister_class;
> @@ -2312,6 +2316,9 @@ static int __init typec_init(void)
>  err_unregister_class:
>  	class_unregister(&typec_class);
>  
> +err_unregister_retimer_class:
> +	class_unregister(&typec_retimer_class);
> +
>  err_unregister_mux_class:
>  	class_unregister(&typec_mux_class);
>  
> diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
> index b531f9853bc0..1bb1da124109 100644
> --- a/drivers/usb/typec/class.h
> +++ b/drivers/usb/typec/class.h
> @@ -76,6 +76,7 @@ extern const struct device_type typec_port_dev_type;
>  #define is_typec_port(dev) ((dev)->type == &typec_port_dev_type)
>  
>  extern struct class typec_mux_class;
> +extern struct class typec_retimer_class;
>  extern struct class typec_class;
>  
>  #if defined(CONFIG_ACPI)
> diff --git a/drivers/usb/typec/retimer.c b/drivers/usb/typec/retimer.c
> new file mode 100644
> index 000000000000..2fa0aeb9363c
> --- /dev/null
> +++ b/drivers/usb/typec/retimer.c
> @@ -0,0 +1,168 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2022 Google LLC
> + *
> + * USB Type-C Retimer support.
> + * Author: Prashant Malani <pmalani@chromium.org>
> + *
> + */
> +
> +#include <linux/device.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/property.h>
> +#include <linux/slab.h>
> +
> +#include "class.h"
> +#include "retimer.h"
> +
> +static bool dev_name_ends_with(struct device *dev, const char *suffix)
> +{
> +	const char *name = dev_name(dev);
> +	const int name_len = strlen(name);
> +	const int suffix_len = strlen(suffix);
> +
> +	if (suffix_len > name_len)
> +		return false;
> +
> +	return strcmp(name + (name_len - suffix_len), suffix) == 0;
> +}
> +
> +static int retimer_fwnode_match(struct device *dev, const void *fwnode)
> +{
> +	return dev_fwnode(dev) == fwnode && dev_name_ends_with(dev, "-retimer");
> +}
> +
> +static void *typec_retimer_match(struct fwnode_handle *fwnode, const char *id, void *data)
> +{
> +	struct device *dev  = class_find_device(&typec_retimer_class, NULL, fwnode,
> +						retimer_fwnode_match);
> +
> +	return dev ? to_typec_retimer(dev) : ERR_PTR(-EPROBE_DEFER);
> +}
> +
> +/**
> + * fwnode_typec_retimer_get - Find USB Type-C retimer.
> + * @fwnode: The caller device node.
> + *
> + * Finds a retimer linked to the caller. This function is primarily meant for the
> + * Type-C drivers. Returns a reference to the retimer on success, NULL if no
> + * matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a connection
> + * was found but the retimer has not been enumerated yet.
> + */
> +struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode)
> +{
> +	struct typec_retimer *retimer;
> +
> +	retimer = fwnode_connection_find_match(fwnode, "retimer-switch", NULL, typec_retimer_match);
> +	if (!IS_ERR_OR_NULL(retimer))
> +		WARN_ON(!try_module_get(retimer->dev.parent->driver->owner));
> +
> +	return retimer;
> +}
> +EXPORT_SYMBOL_GPL(fwnode_typec_retimer_get);
> +
> +/**
> + * typec_retimer_put - Release handle to a retimer.
> + * @retimer: USB Type-C Connector Retimer.
> + *
> + * Decrements reference count for @retimer.
> + */
> +void typec_retimer_put(struct typec_retimer *retimer)
> +{
> +	if (!IS_ERR_OR_NULL(retimer)) {
> +		module_put(retimer->dev.parent->driver->owner);
> +		put_device(&retimer->dev);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(typec_retimer_put);
> +
> +int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
> +{
> +	if (IS_ERR_OR_NULL(retimer))
> +		return 0;
> +
> +	return retimer->set(retimer, state);
> +}
> +EXPORT_SYMBOL_GPL(typec_retimer_set);
> +
> +static void typec_retimer_release(struct device *dev)
> +{
> +	kfree(to_typec_retimer(dev));
> +}
> +
> +static const struct device_type typec_retimer_dev_type = {
> +	.name = "retimer_switch",
> +	.release = typec_retimer_release,
> +};
> +
> +/**
> + * typec_retimer_register - Register a retimer device.
> + * @parent: Parent device.
> + * @desc: Retimer description.
> + *
> + * Some USB Type-C connectors have their physical lines routed through retimers before they
> + * reach muxes or host controllers. In some cases (for example: using alternate modes)
> + * these retimers need to be reconfigured appropriately. This function registers retimer
> + * switches which route and potentially modify the signals on the Type C physical lines
> + * enroute to the host controllers.
> + */
> +struct typec_retimer *
> +typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc)
> +{
> +	struct typec_retimer *retimer;
> +	int ret;
> +
> +	if (!desc || !desc->set)
> +		return ERR_PTR(-EINVAL);
> +
> +	retimer = kzalloc(sizeof(*retimer), GFP_KERNEL);
> +	if (!retimer)
> +		return ERR_PTR(-ENOMEM);
> +
> +	retimer->set = desc->set;
> +
> +	device_initialize(&retimer->dev);
> +	retimer->dev.parent = parent;
> +	retimer->dev.fwnode = desc->fwnode;
> +	retimer->dev.class = &typec_retimer_class;
> +	retimer->dev.type = &typec_retimer_dev_type;
> +	retimer->dev.driver_data = desc->drvdata;
> +	dev_set_name(&retimer->dev, "%s-retimer",
> +		     desc->name ? desc->name : dev_name(parent));
> +
> +	ret = device_add(&retimer->dev);
> +	if (ret) {
> +		dev_err(parent, "failed to register retimer (%d)\n", ret);
> +		put_device(&retimer->dev);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return retimer;
> +}
> +EXPORT_SYMBOL_GPL(typec_retimer_register);
> +
> +/**
> + * typec_retimer_unregister - Unregister retimer device.
> + * @retimer: USB Type-C Connector retimer.
> + *
> + * Unregister retimer that was registered with typec_retimer_register().
> + */
> +void typec_retimer_unregister(struct typec_retimer *retimer)
> +{
> +	if (!IS_ERR_OR_NULL(retimer))
> +		device_unregister(&retimer->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_retimer_unregister);
> +
> +void *typec_retimer_get_drvdata(struct typec_retimer *retimer)
> +{
> +	return dev_get_drvdata(&retimer->dev);
> +}
> +EXPORT_SYMBOL_GPL(typec_retimer_get_drvdata);
> +
> +struct class typec_retimer_class = {
> +	.name = "typec_retimer",
> +	.owner = THIS_MODULE,
> +};
> diff --git a/drivers/usb/typec/retimer.h b/drivers/usb/typec/retimer.h
> new file mode 100644
> index 000000000000..fa15951d4846
> --- /dev/null
> +++ b/drivers/usb/typec/retimer.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __USB_TYPEC_RETIMER__
> +#define __USB_TYPEC_RETIMER__
> +
> +#include <linux/usb/typec_retimer.h>
> +
> +struct typec_retimer {
> +	struct device dev;
> +	typec_retimer_set_fn_t set;
> +};
> +
> +#define to_typec_retimer(_dev_) container_of(_dev_, struct typec_retimer, dev)
> +
> +#endif /* __USB_TYPEC_RETIMER__ */
> diff --git a/include/linux/usb/typec_retimer.h b/include/linux/usb/typec_retimer.h
> new file mode 100644
> index 000000000000..5e036b3360e2
> --- /dev/null
> +++ b/include/linux/usb/typec_retimer.h
> @@ -0,0 +1,45 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef __USB_TYPEC_RETIMER
> +#define __USB_TYPEC_RETIMER
> +
> +#include <linux/property.h>
> +#include <linux/usb/typec.h>
> +
> +struct device;
> +struct typec_retimer;
> +struct typec_altmode;
> +struct fwnode_handle;
> +
> +struct typec_retimer_state {
> +	struct typec_altmode *alt;
> +	unsigned long mode;
> +	void *data;
> +};
> +
> +typedef int (*typec_retimer_set_fn_t)(struct typec_retimer *retimer,
> +				      struct typec_retimer_state *state);
> +
> +struct typec_retimer_desc {
> +	struct fwnode_handle *fwnode;
> +	typec_retimer_set_fn_t set;
> +	const char *name;
> +	void *drvdata;
> +};
> +
> +struct typec_retimer *fwnode_typec_retimer_get(struct fwnode_handle *fwnode);
> +void typec_retimer_put(struct typec_retimer *retimer);
> +int typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state);
> +
> +static inline struct typec_retimer *typec_retimer_get(struct device *dev)
> +{
> +	return fwnode_typec_retimer_get(dev_fwnode(dev));
> +}
> +
> +struct typec_retimer *
> +typec_retimer_register(struct device *parent, const struct typec_retimer_desc *desc);
> +void typec_retimer_unregister(struct typec_retimer *retimer);
> +
> +void *typec_retimer_get_drvdata(struct typec_retimer *retimer);
> +
> +#endif /* __USB_TYPEC_RETIMER */
> -- 
> 2.37.0.rc0.161.g10f37bed90-goog

-- 
heikki

Re: [PATCH 2/9] usb: typec: Add retimer handle to port

[Heikki Krogerus]

Hi,

On Wed, Jun 29, 2022 at 11:32:20PM +0000, Prashant Malani wrote:
> Similar to mux and orientation switch, add a handle for registered
> retimer to the port, so that it has handles to the various switches
> connected to it.
> 
> Signed-off-by: Prashant Malani <pmalani@chromium.org>
> ---
>  drivers/usb/typec/class.c | 8 ++++++++
>  drivers/usb/typec/class.h | 1 +
>  2 files changed, 9 insertions(+)
> 
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 2fa0b3718d23..2bc5fbdb25dd 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -12,6 +12,7 @@
>  #include <linux/slab.h>
>  #include <linux/usb/pd_vdo.h>
>  #include <linux/usb/typec_mux.h>
> +#include <linux/usb/typec_retimer.h>
>  
>  #include "bus.h"
>  #include "class.h"
> @@ -2249,6 +2250,13 @@ struct typec_port *typec_register_port(struct device *parent,
>  		return ERR_PTR(ret);
>  	}
>  
> +	port->retimer = typec_retimer_get(&port->dev);
> +	if (IS_ERR(port->retimer)) {
> +		ret = PTR_ERR(port->retimer);
> +		put_device(&port->dev);
> +		return ERR_PTR(ret);
> +	}
> +
>  	ret = device_add(&port->dev);
>  	if (ret) {
>  		dev_err(parent, "failed to register port (%d)\n", ret);

I think you need to release the reference with typec_retimer_put() in
typec_release().

I guess we can look handle this later, but there can actually be two
onboard retimers for each connector.

thanks,

> diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
> index 1bb1da124109..97520406929e 100644
> --- a/drivers/usb/typec/class.h
> +++ b/drivers/usb/typec/class.h
> @@ -55,6 +55,7 @@ struct typec_port {
>  	enum typec_orientation		orientation;
>  	struct typec_switch		*sw;
>  	struct typec_mux		*mux;
> +	struct typec_retimer		*retimer;
>  
>  	const struct typec_capability	*cap;
>  	const struct typec_operations   *ops;

-- 
heikki

Re: [PATCH 1/9] usb: typec: Add support for retimers

[Mika Westerberg]

On Thu, Jun 30, 2022 at 11:17:59AM +0300, Heikki Krogerus wrote:
> On Wed, Jun 29, 2022 at 11:32:19PM +0000, Prashant Malani wrote:
> > Introduce a retimer device class and associated functions that register
> > and use retimer "switch" devices. These operate in a manner similar to
> > the "mode-switch" and help configure retimers that exist between the
> > Type-C connector and host controller(s).
> > 
> > Type C ports can be linked to retimers using firmware node device
> > references (again, in a manner similar to "mode-switch").
> > 
> > Signed-off-by: Prashant Malani <pmalani@chromium.org>
> 
> Cool! This looks really good to me.
> 
> I'll add Mika here, just to keep him in the loop. Thunderbolt/USB4 can
> control the same physical retimers over the SBU line. Right now there
> is no conflict, but I think we want to later be able to use these
> devices to upgrade the retimer firmware, and that is something that
> the Thunderbolt/USB4 already does. So let's keep an eye on this.
> 
> I wonder, would it make sense to later make the thunderbolt_retimer
> devices also part of the device class that's introduced here? I think
> that way it would be easier to later figure out which
> thunderbolt_retimer and which retimer_switch represent the same
> physical retimer. And perhaps it would also be more clear for the user
> space to have a single device class for the retimers?

I agree this makes sense.

Re: [PATCH 1/9] usb: typec: Add support for retimers

[Prashant Malani]

Hi Heikki,

Thanks for taking a look.

On Thu, Jun 30, 2022 at 1:18 AM Heikki Krogerus
<heikki.krogerus@linux.intel.com> wrote:
>
> On Wed, Jun 29, 2022 at 11:32:19PM +0000, Prashant Malani wrote:
> > Introduce a retimer device class and associated functions that register
> > and use retimer "switch" devices. These operate in a manner similar to
> > the "mode-switch" and help configure retimers that exist between the
> > Type-C connector and host controller(s).
> >
> > Type C ports can be linked to retimers using firmware node device
> > references (again, in a manner similar to "mode-switch").
> >
> > Signed-off-by: Prashant Malani <pmalani@chromium.org>
>
> Cool! This looks really good to me.
>
> I'll add Mika here, just to keep him in the loop. Thunderbolt/USB4 can
> control the same physical retimers over the SBU line. Right now there
> is no conflict, but I think we want to later be able to use these
> devices to upgrade the retimer firmware, and that is something that
> the Thunderbolt/USB4 already does. So let's keep an eye on this.
>
> I wonder, would it make sense to later make the thunderbolt_retimer
> devices also part of the device class that's introduced here? I think
> that way it would be easier to later figure out which
> thunderbolt_retimer and which retimer_switch represent the same
> physical retimer. And perhaps it would also be more clear for the user
> space to have a single device class for the retimers?
>
> Maybe the device class could be named just "retimer", and the device
> type could then be named "typec_retimer" instead of "retimer_switch"?

Sure, I will make this modification in v2.
I assume we can still keep the firmware node handle as "retimer-switch"
to keep it aligned with "mode-switch" and "orientation-switch".

Thanks,

-Prashant

Re: [PATCH 2/9] usb: typec: Add retimer handle to port

[Prashant Malani]

HI Heikki,

On Thu, Jun 30, 2022 at 1:27 AM Heikki Krogerus
<heikki.krogerus@linux.intel.com> wrote:
>
> Hi,
>
> On Wed, Jun 29, 2022 at 11:32:20PM +0000, Prashant Malani wrote:
> > Similar to mux and orientation switch, add a handle for registered
> > retimer to the port, so that it has handles to the various switches
> > connected to it.
> >
> > Signed-off-by: Prashant Malani <pmalani@chromium.org>
> > ---
> >  drivers/usb/typec/class.c | 8 ++++++++
> >  drivers/usb/typec/class.h | 1 +
> >  2 files changed, 9 insertions(+)
> >
> > diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> > index 2fa0b3718d23..2bc5fbdb25dd 100644
> > --- a/drivers/usb/typec/class.c
> > +++ b/drivers/usb/typec/class.c
> > @@ -12,6 +12,7 @@
> >  #include <linux/slab.h>
> >  #include <linux/usb/pd_vdo.h>
> >  #include <linux/usb/typec_mux.h>
> > +#include <linux/usb/typec_retimer.h>
> >
> >  #include "bus.h"
> >  #include "class.h"
> > @@ -2249,6 +2250,13 @@ struct typec_port *typec_register_port(struct device *parent,
> >               return ERR_PTR(ret);
> >       }
> >
> > +     port->retimer = typec_retimer_get(&port->dev);
> > +     if (IS_ERR(port->retimer)) {
> > +             ret = PTR_ERR(port->retimer);
> > +             put_device(&port->dev);
> > +             return ERR_PTR(ret);
> > +     }
> > +
> >       ret = device_add(&port->dev);
> >       if (ret) {
> >               dev_err(parent, "failed to register port (%d)\n", ret);
>
> I think you need to release the reference with typec_retimer_put() in
> typec_release().

I knew I was forgetting something...
I'll fix this in v2.

>
> I guess we can look handle this later, but there can actually be two
> onboard retimers for each connector.

You're referring to the cascaded case right? OK, I'll bear this in mind for
later series (right now the EC exposes just 1 interface for retimer).

Thanks,

-Prashant