[RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows

[RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows

[Daniel Scally]

Currently on platforms designed for Windows, connections between CIO2 and
sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
driver to compensate by building software_node connections, parsing the
connection properties from the sensor's SSDB buffer. 

Suggested-by: Jordan Hand <jorhand@linux.microsoft.com>

Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
This patch is dependent on another (which implements the software node graph
family of functions):

https://lore.kernel.org/linux-media/20200915232827.3416-1-djrscally@gmail.com/

Major changes for the v2 (on top of a myriad of fixes probably too minor to
call out - thank you everybody for the comments)

* Built against media_tree instead of linus's tree - there's no T: entry in
maintainers for the ipu3-cio2 driver but I see there're recent changes in 
media_tree so thought this was the better option.

* Moved from a separate module to integrating the changes into the ipu3-cio2
driver itself.

There was some difference of opinion about the desirability of this, but I
think that this option won out. I have attempted to address the concerns about
bloating everyone's kernel by conditionally compiling the extension in based on
config settings; although I don't have an ipu3 device that doesn't need these
changes (so haven't been able to test that properly) - it certainly seems to be
working as expected.

Compiling things in like this did require renaming either the module or the
ipu3-cio2.c file, I chose the module to keep patch size down - let me know if
that was the wrong choice.

* Error handling has been switched so each function cleans itself up 
properly rather than one single "clean up everything" function.

* Indentation fixed for create_endpoint_properties()

* Creation of the software_nodes moved to its own function

* Clock frequency property moved to the device fwnode instead of the endpoint's

* Reprobe of the sensors added at the end of connect_supported_devices(). This
is needed to allow probe() calls from the drivers to pick up new properties.
This required some unusual behaviour; because we're overwriting the fwnode
of the device ACPI device to driver matching will no longer work. To work
around that, I'm cloning the driver but adding an i2c_device_id table to it
so that fallback i2c matching works. This driver is unregistered if the module
is removed. I don't especially like this solution, but I couldn't see a better
way to solve this problem.

Suggested changes that I didn't make:

Sakari - link-frequencies doesn't seem to be available in the SSDB buffer or
anywhere else that I can see in DSDT unfortunately, so I didn't add that as a
property. Also, I left the iterator as an int until that discussion came to a
conclusive answer.

 MAINTAINERS                                |   1 +
 drivers/media/pci/intel/ipu3/Kconfig       |  15 +
 drivers/media/pci/intel/ipu3/Makefile      |   8 +-
 drivers/media/pci/intel/ipu3/cio2-bridge.c | 433 +++++++++++++++++++++
 drivers/media/pci/intel/ipu3/cio2-bridge.h | 110 ++++++
 drivers/media/pci/intel/ipu3/ipu3-cio2.c   |  21 +
 drivers/media/pci/intel/ipu3/ipu3-cio2.h   |  18 +
 7 files changed, 605 insertions(+), 1 deletion(-)
 create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.c
 create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 43a025039..0b4481ef2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8848,6 +8848,7 @@ INTEL IPU3 CSI-2 CIO2 DRIVER
 M:	Yong Zhi <yong.zhi@intel.com>
 M:	Sakari Ailus <sakari.ailus@linux.intel.com>
 M:	Bingbu Cao <bingbu.cao@intel.com>
+M:	Dan Scally <djrscally@gmail.com>
 R:	Tianshu Qiu <tian.shu.qiu@intel.com>
 L:	linux-media@vger.kernel.org
 S:	Maintained
diff --git a/drivers/media/pci/intel/ipu3/Kconfig b/drivers/media/pci/intel/ipu3/Kconfig
index 82d7f17e6..04b2d579e 100644
--- a/drivers/media/pci/intel/ipu3/Kconfig
+++ b/drivers/media/pci/intel/ipu3/Kconfig
@@ -16,3 +16,18 @@ config VIDEO_IPU3_CIO2
 	  Say Y or M here if you have a Skylake/Kaby Lake SoC with MIPI CSI-2
 	  connected camera.
 	  The module will be called ipu3-cio2.
+
+config CIO2_BRIDGE
+	bool "IPU3 CIO2 Sensors Bridge"
+	depends on VIDEO_IPU3_CIO2
+	help
+	  This extension provides an API for the ipu3-cio2 driver to create
+	  connections to cameras that are hidden in SSDB buffer in ACPI. It
+	  can be used to enable support for cameras in detachable / hybrid
+	  devices that ship with Windows.
+
+	  Say y here if your device is a detachable / hybrid laptop that comes
+	  with Windows installed by the OEM, for example the Microsoft Surface
+	  line, Lenovo Miix line or Dell 7285.
+
+	  If in doubt, say n here.
diff --git a/drivers/media/pci/intel/ipu3/Makefile b/drivers/media/pci/intel/ipu3/Makefile
index 98ddd5bea..4810b34bf 100644
--- a/drivers/media/pci/intel/ipu3/Makefile
+++ b/drivers/media/pci/intel/ipu3/Makefile
@@ -1,2 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
+obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2-driver.o
+
+ipu3-cio2-driver-objs += ipu3-cio2.o
+
+ifeq ($(CONFIG_CIO2_BRIDGE), y)
+ipu3-cio2-driver-objs += cio2-bridge.o
+endif
diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.c b/drivers/media/pci/intel/ipu3/cio2-bridge.c
new file mode 100644
index 000000000..14d722dea
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/fwnode.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/property.h>
+#include <media/v4l2-subdev.h>
+
+#include "cio2-bridge.h"
+
+/*
+ * Extend this array with ACPI Hardware ID's of devices known to be
+ * working
+ */
+
+static const struct ipu3_sensor supported_devices[] = {
+	IPU3_SENSOR("INT33BE", "INT33BE:00"),
+	IPU3_SENSOR("OVTI2680", "OVTI2680:00"),
+	IPU3_SENSOR("OVTI5648", "OVTI5648:00")
+};
+
+static struct software_node cio2_hid_node = { CIO2_HID, };
+
+static struct cio2_bridge bridge;
+
+static const char * const port_names[] = {
+	"port0", "port1", "port2", "port3"
+};
+
+static const struct property_entry remote_endpoints[] = {
+	PROPERTY_ENTRY_REF("remote-endpoint", /* Sensor 0, Sensor Property */
+			   &bridge.sensors[0].swnodes[SWNODE_CIO2_ENDPOINT]),
+	PROPERTY_ENTRY_REF("remote-endpoint", /* Sensor 0, CIO2 Property */
+			   &bridge.sensors[0].swnodes[SWNODE_SENSOR_ENDPOINT]),
+	PROPERTY_ENTRY_REF("remote-endpoint",
+			   &bridge.sensors[1].swnodes[SWNODE_CIO2_ENDPOINT]),
+	PROPERTY_ENTRY_REF("remote-endpoint",
+			   &bridge.sensors[1].swnodes[SWNODE_SENSOR_ENDPOINT]),
+	PROPERTY_ENTRY_REF("remote-endpoint",
+			   &bridge.sensors[2].swnodes[SWNODE_CIO2_ENDPOINT]),
+	PROPERTY_ENTRY_REF("remote-endpoint",
+			   &bridge.sensors[2].swnodes[SWNODE_SENSOR_ENDPOINT]),
+	PROPERTY_ENTRY_REF("remote-endpoint",
+			   &bridge.sensors[3].swnodes[SWNODE_CIO2_ENDPOINT]),
+	PROPERTY_ENTRY_REF("remote-endpoint",
+			   &bridge.sensors[3].swnodes[SWNODE_SENSOR_ENDPOINT]),
+};
+
+static int read_acpi_block(struct device *dev, char *id, void *data, u32 size)
+{
+	union acpi_object *obj;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	struct acpi_handle *handle = ACPI_HANDLE(dev);
+	acpi_status status;
+	int ret;
+
+	status = acpi_evaluate_object(handle, id, NULL, &buffer);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	obj = buffer.pointer;
+	if (!obj || obj->type != ACPI_TYPE_BUFFER) {
+		dev_err(dev, "Could't read acpi buffer\n");
+		ret = -ENODEV;
+		goto err_free_buff;
+	}
+
+	if (obj->buffer.length > size) {
+		dev_err(dev, "Given buffer is too small\n");
+		ret = -ENODEV;
+		goto err_free_buff;
+	}
+
+	memcpy(data, obj->buffer.pointer, obj->buffer.length);
+	kfree(buffer.pointer);
+
+	return obj->buffer.length;
+err_free_buff:
+	kfree(buffer.pointer);
+	return ret;
+}
+
+static int get_acpi_ssdb_sensor_data(struct device *dev,
+				     struct sensor_bios_data *sensor)
+{
+	struct sensor_bios_data_packed sensor_data;
+	int ret;
+
+	ret = read_acpi_block(dev, "SSDB", &sensor_data, sizeof(sensor_data));
+	if (ret < 0)
+		return ret;
+
+	sensor->link = sensor_data.link;
+	sensor->lanes = sensor_data.lanes;
+	sensor->mclkspeed = sensor_data.mclkspeed;
+	sensor->degree = sensor_data.degree;
+
+	return 0;
+}
+
+static int create_fwnode_properties(struct sensor *sensor,
+				    struct sensor_bios_data *ssdb)
+{
+	struct property_entry *ep_props;
+	struct property_entry *cio2_props;
+	struct property_entry *dev_props;
+	u32 *data_lanes;
+	int i;
+
+	/* device fwnode properties */
+	dev_props = kcalloc(3, sizeof(*dev_props), GFP_KERNEL);
+	if (!dev_props)
+		return -ENOMEM;
+
+	dev_props[0] = PROPERTY_ENTRY_U32("clock-frequency", ssdb->mclkspeed);
+	dev_props[1] = PROPERTY_ENTRY_U8("rotation", ssdb->degree);
+
+	memcpy(sensor->dev_props, dev_props, sizeof(*dev_props) * 3);
+	kfree(dev_props);
+
+	/* endpoint fwnode properties */
+
+	data_lanes = devm_kmalloc_array(sensor->dev, ssdb->lanes, sizeof(u32),
+					GFP_KERNEL);
+
+	if (!data_lanes)
+		return -ENOMEM;
+
+	for (i = 0; i < ssdb->lanes; i++)
+		data_lanes[i] = i + 1;
+
+	ep_props = kcalloc(4, sizeof(*ep_props), GFP_KERNEL);
+	if (!ep_props)
+		return -ENOMEM;
+
+	ep_props[0] = PROPERTY_ENTRY_U32("bus-type", 5);
+	ep_props[1] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
+						   data_lanes,
+						   ssdb->lanes);
+	ep_props[2] = remote_endpoints[(bridge.n_sensors * 2) + ENDPOINT_SENSOR];
+
+	memcpy(sensor->ep_props, ep_props, sizeof(*ep_props) * 4);
+	kfree(ep_props);
+
+	/* cio2 endpoint props */
+
+	cio2_props = kcalloc(3, sizeof(*cio2_props), GFP_KERNEL);
+	if (!cio2_props)
+		return -ENOMEM;
+
+	cio2_props[0] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
+						     data_lanes,
+						     ssdb->lanes);
+	cio2_props[1] = remote_endpoints[(bridge.n_sensors * 2) + ENDPOINT_CIO2];
+
+	memcpy(sensor->cio2_props, cio2_props, sizeof(*cio2_props) * 3);
+	kfree(cio2_props);
+
+	return 0;
+}
+
+static int create_connection_swnodes(struct sensor *sensor,
+				     struct sensor_bios_data *ssdb)
+{
+	struct software_node *nodes;
+
+	nodes = kcalloc(6, sizeof(*nodes), GFP_KERNEL);
+	if (!nodes)
+		return -ENOMEM;
+
+	nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
+					       sensor->dev_props);
+	nodes[SWNODE_SENSOR_PORT] = NODE_PORT("port0",
+					      &sensor->swnodes[SWNODE_SENSOR_HID]);
+	nodes[SWNODE_SENSOR_ENDPOINT] = NODE_ENDPOINT("endpoint0",
+						      &sensor->swnodes[SWNODE_SENSOR_PORT],
+						      sensor->ep_props);
+	nodes[SWNODE_CIO2_PORT] = NODE_PORT(port_names[ssdb->link],
+					    &cio2_hid_node);
+	nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT("endpoint0",
+						    &sensor->swnodes[SWNODE_CIO2_PORT],
+						    sensor->cio2_props);
+
+	memcpy(sensor->swnodes, nodes, sizeof(*nodes) * 6);
+	kfree(nodes);
+
+	return 0;
+}
+
+static void cio2_bridge_unregister_sensors(void)
+{
+	int i, j;
+	struct sensor *sensor;
+
+	for (i = 0; i < bridge.n_sensors; i++) {
+		sensor = &bridge.sensors[i];
+
+		for (j = 4; j >= 0; j--)
+			software_node_unregister(&sensor->swnodes[j]);
+
+		/*
+		 * Give the sensor its original fwnode back or the next time
+		 * it's probed will fail, because ACPI matching doesn't work
+		 * when your fwnode doesn't have acpi_device_fwnode_ops.
+		 */
+		sensor->dev->fwnode = sensor->fwnode;
+		fwnode_handle_put(sensor->fwnode);
+
+		device_release_driver(sensor->dev);
+		i2c_del_driver(&sensor->new_drv);
+		device_reprobe(sensor->dev);
+		put_device(sensor->dev);
+	}
+}
+
+/*
+ * We have to reprobe the sensor in order for .probe() calls to be able to read
+ * the fwnode properties we set, but having just overwritten the ACPI fwnode
+ * the usual matching won't work by default. We need to clone the existing
+ * driver but add an i2c_device_id so the matching works.
+ */
+static int cio2_bridge_reprobe_sensor(struct sensor *sensor, int index)
+{
+	struct i2c_client *client;
+	int ret;
+
+	client = container_of(sensor->dev, struct i2c_client, dev);
+
+	sensor->old_drv = container_of(sensor->dev->driver, struct i2c_driver,
+				       driver);
+
+	sensor->new_drv.driver.name = supported_devices[index].i2c_id[0].name;
+	sensor->new_drv.probe_new = sensor->old_drv->probe_new;
+	sensor->new_drv.remove = sensor->old_drv->remove;
+	sensor->new_drv.id_table = supported_devices[index].i2c_id;
+
+	device_release_driver(sensor->dev);
+
+	ret = i2c_add_driver(&sensor->new_drv);
+	if (ret)
+		return ret;
+
+	ret = device_reprobe(sensor->dev);
+	if (ret)
+		goto err_remove_new_drv;
+
+	return 0;
+
+err_remove_new_drv:
+	i2c_del_driver(&sensor->new_drv);
+
+	return ret;
+}
+
+static int connect_supported_devices(void)
+{
+	struct acpi_device *adev;
+	struct device *dev;
+	struct sensor_bios_data ssdb;
+	struct sensor *sensor;
+	struct fwnode_handle *fwnode;
+	struct v4l2_subdev *sd;
+	int i, j, ret;
+
+	ret = 0;
+
+	for (i = 0; i < ARRAY_SIZE(supported_devices); i++) {
+		adev = acpi_dev_get_first_match_dev(supported_devices[i].hid,
+						    NULL, -1);
+		if (!adev)
+			continue;
+
+		dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
+		if (!dev) {
+			ret = -EPROBE_DEFER;
+			goto err_rollback;
+		}
+
+		/*
+		 * We need to clone the driver of any sensors that we connect,
+		 * so if they're probing we need to wait until they're finished
+		 */
+
+		if (dev->links.status == DL_DEV_PROBING) {
+			ret = -EPROBE_DEFER;
+			goto err_free_dev;
+		}
+
+		/*
+		 * If a sensor has no driver, we want to continue to try and
+		 * link others
+		 */
+		sd = dev_get_drvdata(dev);
+		if (!sd)
+			goto cont_free_dev;
+
+		sensor = &bridge.sensors[bridge.n_sensors];
+		sensor->dev = dev;
+
+		snprintf(sensor->name, 20, "%s", supported_devices[i].hid);
+
+		sensor->fwnode = fwnode_handle_get(dev->fwnode);
+		if (!sensor->fwnode)
+			goto err_free_dev;
+
+		ret = get_acpi_ssdb_sensor_data(dev, &ssdb);
+		if (ret)
+			goto err_free_fwnode;
+
+		ret = create_fwnode_properties(sensor, &ssdb);
+		if (ret)
+			goto err_free_fwnode;
+
+		ret = create_connection_swnodes(sensor, &ssdb);
+		if (ret)
+			goto err_free_fwnode;
+
+		ret = software_node_register_nodes(sensor->swnodes);
+		if (ret)
+			goto err_free_fwnode;
+
+		fwnode = software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
+		if (!fwnode) {
+			ret = -ENODEV;
+			goto err_free_swnodes;
+		}
+
+		fwnode->secondary = ERR_PTR(-ENODEV);
+		dev->fwnode = fwnode;
+
+		ret = cio2_bridge_reprobe_sensor(sensor, i);
+		if (ret)
+			goto err_free_swnodes;
+
+		pr_info("cio2-bridge: Found supported device %s\n",
+			supported_devices[i].hid);
+
+		bridge.n_sensors++;
+		continue;
+cont_free_dev:
+		put_device(dev);
+		continue;
+err_free_swnodes:
+		for (j = 4; j >= 0; j--)
+			software_node_unregister(&sensor->swnodes[j]);
+err_free_fwnode:
+		fwnode_handle_put(sensor->fwnode);
+err_free_dev:
+		put_device(dev);
+err_rollback:
+		/*
+		 * If an iteration of this loop results in -EPROBE_DEFER then
+		 * we need to roll back any sensors that were successfully
+		 * registered. Any other error and we'll skip that step, as
+		 * it seems better to have one successfully connected sensor.
+		 */
+
+		if (ret == -EPROBE_DEFER)
+			cio2_bridge_unregister_sensors();
+
+		break;
+	}
+
+	return ret;
+}
+
+int cio2_bridge_build(struct pci_dev *cio2)
+{
+	struct fwnode_handle *fwnode;
+	int ret;
+
+	pci_dev_get(cio2);
+
+	ret = software_node_register(&cio2_hid_node);
+	if (ret < 0) {
+		pr_err("cio2-bridge: Failed to register the CIO2 HID node\n");
+		goto err_put_cio2;
+	}
+
+	ret = connect_supported_devices();
+	if (ret == -EPROBE_DEFER)
+		goto err_unregister_cio2;
+
+	if (bridge.n_sensors == 0) {
+		ret = -EPROBE_DEFER;
+		goto err_unregister_cio2;
+	}
+
+	pr_info("cio2-bridge: Connected %d cameras\n", bridge.n_sensors);
+
+	fwnode = software_node_fwnode(&cio2_hid_node);
+	if (!fwnode) {
+		pr_err("Error getting fwnode from cio2 software_node\n");
+		ret = -ENODEV;
+		goto err_unregister_sensors;
+	}
+
+	/*
+	 * We store the pci_dev's existing fwnode, because in the event we
+	 * want to reload the ipu3-cio2 driver we need to give the device its
+	 * original fwnode back to prevent problems.
+	 */
+
+	bridge.cio2_fwnode = fwnode_handle_get(cio2->dev.fwnode);
+
+	fwnode->secondary = ERR_PTR(-ENODEV);
+	cio2->dev.fwnode = fwnode;
+
+	return 0;
+
+err_unregister_sensors:
+	cio2_bridge_unregister_sensors();
+err_unregister_cio2:
+	software_node_unregister(&cio2_hid_node);
+err_put_cio2:
+	pci_dev_put(cio2);
+
+	return ret;
+}
+
+void cio2_bridge_burn(struct pci_dev *cio2)
+{
+	cio2->dev.fwnode = bridge.cio2_fwnode;
+	fwnode_handle_put(bridge.cio2_fwnode);
+	pci_dev_put(cio2);
+
+	cio2_bridge_unregister_sensors();
+
+	software_node_unregister(&cio2_hid_node);
+}
diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.h b/drivers/media/pci/intel/ipu3/cio2-bridge.h
new file mode 100644
index 000000000..16ff262f3
--- /dev/null
+++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __CIO2_BRIDGE_H
+#define __CIO2_BRIDGE_H
+#define __NO_VERSION__
+
+#define MAX_CONNECTED_DEVICES			4
+#define SWNODE_SENSOR_HID			0
+#define SWNODE_SENSOR_PORT			1
+#define SWNODE_SENSOR_ENDPOINT			2
+#define SWNODE_CIO2_PORT			3
+#define SWNODE_CIO2_ENDPOINT			4
+#define SWNODE_NULL_TERMINATOR			5
+
+#define CIO2_HID				"INT343E"
+#define CIO2_PCI_ID				0x9d32
+
+#define ENDPOINT_SENSOR				0
+#define ENDPOINT_CIO2				1
+
+#define NODE_SENSOR(_HID, _PROPS)		\
+	((const struct software_node) {		\
+		.name = _HID,			\
+		.properties = _PROPS		\
+	})
+
+#define NODE_PORT(_PORT, _SENSOR_NODE)		\
+	((const struct software_node) {		\
+		_PORT,				\
+		_SENSOR_NODE,			\
+	})
+
+#define NODE_ENDPOINT(_EP, _PORT, _PROPS)	\
+	((const struct software_node) {		\
+		_EP,				\
+		_PORT,				\
+		_PROPS,				\
+	})
+
+#define IPU3_SENSOR(_HID, _CLIENT)		\
+	{					\
+		.hid = _HID,			\
+		.i2c_id = {			\
+			{_CLIENT, 0},		\
+			{ },			\
+		}				\
+	}
+
+struct ipu3_sensor {
+	const char hid[20];
+	const struct i2c_device_id i2c_id[2];
+};
+
+struct sensor {
+	char name[20];
+	struct device *dev;
+	struct software_node swnodes[6];
+	struct property_entry dev_props[3];
+	struct property_entry ep_props[4];
+	struct property_entry cio2_props[3];
+	struct fwnode_handle *fwnode;
+	struct i2c_driver *old_drv;
+	struct i2c_driver new_drv;
+};
+
+struct cio2_bridge {
+	int n_sensors;
+	struct sensor sensors[MAX_CONNECTED_DEVICES];
+	struct fwnode_handle *cio2_fwnode;
+};
+
+/* Data representation as it is in ACPI SSDB buffer */
+struct sensor_bios_data_packed {
+	u8 version;
+	u8 sku;
+	u8 guid_csi2[16];
+	u8 devfunction;
+	u8 bus;
+	u32 dphylinkenfuses;
+	u32 clockdiv;
+	u8 link;
+	u8 lanes;
+	u32 csiparams[10];
+	u32 maxlanespeed;
+	u8 sensorcalibfileidx;
+	u8 sensorcalibfileidxInMBZ[3];
+	u8 romtype;
+	u8 vcmtype;
+	u8 platforminfo;
+	u8 platformsubinfo;
+	u8 flash;
+	u8 privacyled;
+	u8 degree;
+	u8 mipilinkdefined;
+	u32 mclkspeed;
+	u8 controllogicid;
+	u8 reserved1[3];
+	u8 mclkport;
+	u8 reserved2[13];
+} __attribute__((__packed__));
+
+/* Fields needed by bridge driver */
+struct sensor_bios_data {
+	struct device *dev;
+	u8 link;
+	u8 lanes;
+	u8 degree;
+	u32 mclkspeed;
+};
+
+#endif
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.c b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
index 4e598e937..ea18d8c81 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.c
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.c
@@ -1711,8 +1711,26 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
 			  const struct pci_device_id *id)
 {
 	struct cio2_device *cio2;
+	struct fwnode_handle *endpoint;
 	int r;
 
+	/*
+	 * On some platforms no connections to sensors are defined in firmware,
+	 * if the device has no endpoints then we can try to build those as
+	 * software_nodes parsed from SSDB.
+	 *
+	 * This may EPROBE_DEFER if supported devices are found defined in ACPI
+	 * but not yet ready for use (either not attached to the i2c bus yet,
+	 * or not done probing themselves).
+	 */
+
+	endpoint = fwnode_graph_get_next_endpoint(pci_dev->dev.fwnode, NULL);
+	if (!endpoint) {
+		r = cio2_bridge_build(pci_dev);
+		if (r)
+			return r;
+	}
+
 	cio2 = devm_kzalloc(&pci_dev->dev, sizeof(*cio2), GFP_KERNEL);
 	if (!cio2)
 		return -ENOMEM;
@@ -1820,6 +1838,9 @@ static void cio2_pci_remove(struct pci_dev *pci_dev)
 {
 	struct cio2_device *cio2 = pci_get_drvdata(pci_dev);
 
+	if (is_software_node(pci_dev->dev.fwnode))
+		cio2_bridge_burn(pci_dev);
+
 	media_device_unregister(&cio2->media_dev);
 	v4l2_async_notifier_unregister(&cio2->notifier);
 	v4l2_async_notifier_cleanup(&cio2->notifier);
diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.h b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
index 549b08f88..45791208d 100644
--- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
+++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
@@ -436,4 +436,22 @@ static inline struct cio2_queue *vb2q_to_cio2_queue(struct vb2_queue *vq)
 	return container_of(vq, struct cio2_queue, vbq);
 }
 
+#ifdef CONFIG_CIO2_BRIDGE
+
+int cio2_bridge_build(struct pci_dev *cio2);
+void cio2_bridge_burn(struct pci_dev *cio2);
+
+#else
+
+int cio2_bridge_build(struct pci_dev *cio2)
+{
+	return 0;
+}
+
+void cio2_bridge_burn(struct pci_dev *cio2)
+{
+}
+
+#endif
+
 #endif
-- 
2.17.1

Re: [RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows

[Andy Shevchenko]

On Thu, Oct 01, 2020 at 10:33:26AM +0100, Daniel Scally wrote:

Awesome work!
My, almost minor, comments below.

> Currently on platforms designed for Windows, connections between CIO2 and
> sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
> driver to compensate by building software_node connections, parsing the
> connection properties from the sensor's SSDB buffer. 

Drop trailing space here and in other places if any.

> Suggested-by: Jordan Hand <jorhand@linux.microsoft.com>
> 
> Signed-off-by: Daniel Scally <djrscally@gmail.com>

In the tag block should not be blank lines.

...

> * Built against media_tree instead of linus's tree - there's no T: entry in
> maintainers for the ipu3-cio2 driver but I see there're recent changes in 
> media_tree so thought this was the better option.

Make sense to include T: entry as well (maybe as a separate patch).

...

> +config CIO2_BRIDGE
> +	bool "IPU3 CIO2 Sensors Bridge"
> +	depends on VIDEO_IPU3_CIO2
> +	help
> +	  This extension provides an API for the ipu3-cio2 driver to create
> +	  connections to cameras that are hidden in SSDB buffer in ACPI. It
> +	  can be used to enable support for cameras in detachable / hybrid
> +	  devices that ship with Windows.
> +
> +	  Say y here if your device is a detachable / hybrid laptop that comes

y -> Y

> +	  with Windows installed by the OEM, for example the Microsoft Surface
> +	  line, Lenovo Miix line or Dell 7285.

Reads better in a form of an enumeration, like

		- Microsoft Surface (all existing)
		- Lenovo Miix (all existing)
		- Dell 7285

> +	  If in doubt, say n here.

n -> N

...

> -obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
> +obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2-driver.o
> +
> +ipu3-cio2-driver-objs += ipu3-cio2.o
> +
> +ifeq ($(CONFIG_CIO2_BRIDGE), y)
> +ipu3-cio2-driver-objs += cio2-bridge.o
> +endif

objs is for userspace tools, here use

ipu3-cio2-driver-y += ipu3-cio2.o
ipu3-cio2-driver-$(CONFIG_CIO2_BRIDGE) = cio2-bridge.o

And actually would be nice to keep the name, so means rename ipu3-cio2.c to
something like cio2-main.c. In such case you will have:

obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o

ipu3-cio2-y += cio2-main.o
ipu3-cio2-$(CONFIG_CIO2_BRIDGE) = cio2-bridge.o

...

> +// SPDX-License-Identifier: GPL-2.0

Author line perhaps?

...

> +/*
> + * Extend this array with ACPI Hardware ID's of devices known to be
> + * working
> + */

> +

Redundant blank like.

> +static const struct ipu3_sensor supported_devices[] = {
> +	IPU3_SENSOR("INT33BE", "INT33BE:00"),
> +	IPU3_SENSOR("OVTI2680", "OVTI2680:00"),
> +	IPU3_SENSOR("OVTI5648", "OVTI5648:00")

In such cases please leave comma at the last item as well. Easier to extend w/o
an additional churn.

On top of that, please avoid putting *instance* names, i.e. the second
parameters in your macro call. What code should do is to take _HID (first
parameter) and call acpi_dev_match_first_dev() or so.

> +};

> +static struct software_node cio2_hid_node = { CIO2_HID, };

Here, nevertheless, comma can be removed, since update will need to change
entire line anyway.

> +static const char * const port_names[] = {
> +	"port0", "port1", "port2", "port3"
> +};

+ Comma (can be prolonged in the next / previous lines).

...

> +static int read_acpi_block(struct device *dev, char *id, void *data, u32 size)
> +{
> +	union acpi_object *obj;
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	struct acpi_handle *handle = ACPI_HANDLE(dev);
> +	acpi_status status;
> +	int ret;
> +
> +	status = acpi_evaluate_object(handle, id, NULL, &buffer);
> +	if (ACPI_FAILURE(status))
> +		return -ENODEV;
> +
> +	obj = buffer.pointer;
> +	if (!obj || obj->type != ACPI_TYPE_BUFFER) {

!obj case doesn't require freeing and I would say the error message can be
amended in such case.

> +		dev_err(dev, "Could't read acpi buffer\n");
> +		ret = -ENODEV;
> +		goto err_free_buff;
> +	}
> +
> +	if (obj->buffer.length > size) {
> +		dev_err(dev, "Given buffer is too small\n");
> +		ret = -ENODEV;
> +		goto err_free_buff;
> +	}
> +
> +	memcpy(data, obj->buffer.pointer, obj->buffer.length);

> +	kfree(buffer.pointer);
> +
> +	return obj->buffer.length;
> +err_free_buff:
> +	kfree(buffer.pointer);
> +	return ret;

This may be deduplicated by adding ret = obj->buffer.length; in the success
branch. In such case the label would be named out_free_buf.

> +}

...

> +static int create_fwnode_properties(struct sensor *sensor,
> +				    struct sensor_bios_data *ssdb)
> +{
> +	struct property_entry *ep_props;
> +	struct property_entry *cio2_props;
> +	struct property_entry *dev_props;
> +	u32 *data_lanes;
> +	int i;

> +	/* device fwnode properties */
> +	dev_props = kcalloc(3, sizeof(*dev_props), GFP_KERNEL);
> +	if (!dev_props)
> +		return -ENOMEM;
> +
> +	dev_props[0] = PROPERTY_ENTRY_U32("clock-frequency", ssdb->mclkspeed);
> +	dev_props[1] = PROPERTY_ENTRY_U8("rotation", ssdb->degree);
> +
> +	memcpy(sensor->dev_props, dev_props, sizeof(*dev_props) * 3);
> +	kfree(dev_props);

Why you can't do it on stack?

> +	/* endpoint fwnode properties */

> +

Redundant blank like

> +	data_lanes = devm_kmalloc_array(sensor->dev, ssdb->lanes, sizeof(u32),
> +					GFP_KERNEL);
> +
> +	if (!data_lanes)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < ssdb->lanes; i++)
> +		data_lanes[i] = i + 1;

> +	ep_props = kcalloc(4, sizeof(*ep_props), GFP_KERNEL);
> +	if (!ep_props)
> +		return -ENOMEM;
> +
> +	ep_props[0] = PROPERTY_ENTRY_U32("bus-type", 5);
> +	ep_props[1] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
> +						   data_lanes,
> +						   ssdb->lanes);
> +	ep_props[2] = remote_endpoints[(bridge.n_sensors * 2) + ENDPOINT_SENSOR];
> +
> +	memcpy(sensor->ep_props, ep_props, sizeof(*ep_props) * 4);
> +	kfree(ep_props);

Why can't be done on stack?

> +
> +	/* cio2 endpoint props */
> +
> +	cio2_props = kcalloc(3, sizeof(*cio2_props), GFP_KERNEL);
> +	if (!cio2_props)
> +		return -ENOMEM;
> +
> +	cio2_props[0] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
> +						     data_lanes,
> +						     ssdb->lanes);
> +	cio2_props[1] = remote_endpoints[(bridge.n_sensors * 2) + ENDPOINT_CIO2];
> +
> +	memcpy(sensor->cio2_props, cio2_props, sizeof(*cio2_props) * 3);
> +	kfree(cio2_props);

Ditto.

Something like
	union {
		...
		cio2_properties[3];
	} properties;

	memset(properties, 0, sizeof(properties));

(and please spell properties instead of props)

> +	return 0;
> +}
> +
> +static int create_connection_swnodes(struct sensor *sensor,
> +				     struct sensor_bios_data *ssdb)
> +{
> +	struct software_node *nodes;
> +
> +	nodes = kcalloc(6, sizeof(*nodes), GFP_KERNEL);
> +	if (!nodes)
> +		return -ENOMEM;
> +
> +	nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
> +					       sensor->dev_props);
> +	nodes[SWNODE_SENSOR_PORT] = NODE_PORT("port0",
> +					      &sensor->swnodes[SWNODE_SENSOR_HID]);
> +	nodes[SWNODE_SENSOR_ENDPOINT] = NODE_ENDPOINT("endpoint0",
> +						      &sensor->swnodes[SWNODE_SENSOR_PORT],
> +						      sensor->ep_props);
> +	nodes[SWNODE_CIO2_PORT] = NODE_PORT(port_names[ssdb->link],
> +					    &cio2_hid_node);
> +	nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT("endpoint0",
> +						    &sensor->swnodes[SWNODE_CIO2_PORT],
> +						    sensor->cio2_props);
> +
> +	memcpy(sensor->swnodes, nodes, sizeof(*nodes) * 6);
> +	kfree(nodes);

Also, why not on stack?

> +	return 0;
> +}

...

> +		for (j = 4; j >= 0; j--)
> +			software_node_unregister(&sensor->swnodes[j]);

Seems we may need a simple helper for this (test_printf.c has similar case),
so, what about do it here for now and probably then move to somewhere like
swnode.h or whatever holds it.

static inline software_node_unregister_nodes_reverse(const struct software_node *nodes)
{
	unsigned int i = 0;

	while (nodes[i].name)
		i++;
	while (i--)
		software_node_unregister(&nodes[i]);
}

...

> +	client = container_of(sensor->dev, struct i2c_client, dev);

Shouldn't be rather i2c_verify_client() ?

...

> +	sensor->old_drv = container_of(sensor->dev->driver, struct i2c_driver,
> +				       driver);

to_i2c_driver() ?

...

> +	ret = 0;
> +

No need to have a blank line here (check other similar places in the code).

> +	for (i = 0; i < ARRAY_SIZE(supported_devices); i++) {

> +		adev = acpi_dev_get_first_match_dev(supported_devices[i].hid,
> +						    NULL, -1);

Keep it one line, easy to read.

> +		if (!adev)
> +			continue;
> +
> +		dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
> +		if (!dev) {
> +			ret = -EPROBE_DEFER;
> +			goto err_rollback;
> +		}
> +
> +		/*
> +		 * We need to clone the driver of any sensors that we connect,
> +		 * so if they're probing we need to wait until they're finished
> +		 */
> +
> +		if (dev->links.status == DL_DEV_PROBING) {
> +			ret = -EPROBE_DEFER;
> +			goto err_free_dev;
> +		}
> +
> +		/*
> +		 * If a sensor has no driver, we want to continue to try and
> +		 * link others
> +		 */
> +		sd = dev_get_drvdata(dev);
> +		if (!sd)
> +			goto cont_free_dev;
> +
> +		sensor = &bridge.sensors[bridge.n_sensors];
> +		sensor->dev = dev;
> +
> +		snprintf(sensor->name, 20, "%s", supported_devices[i].hid);

include/linux/mod_devicetable.h:454:#define I2C_NAME_SIZE       20

> +		sensor->fwnode = fwnode_handle_get(dev->fwnode);
> +		if (!sensor->fwnode)
> +			goto err_free_dev;
> +
> +		ret = get_acpi_ssdb_sensor_data(dev, &ssdb);
> +		if (ret)
> +			goto err_free_fwnode;
> +
> +		ret = create_fwnode_properties(sensor, &ssdb);
> +		if (ret)
> +			goto err_free_fwnode;
> +
> +		ret = create_connection_swnodes(sensor, &ssdb);
> +		if (ret)
> +			goto err_free_fwnode;
> +
> +		ret = software_node_register_nodes(sensor->swnodes);
> +		if (ret)
> +			goto err_free_fwnode;
> +
> +		fwnode = software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
> +		if (!fwnode) {
> +			ret = -ENODEV;
> +			goto err_free_swnodes;
> +		}
> +
> +		fwnode->secondary = ERR_PTR(-ENODEV);
> +		dev->fwnode = fwnode;
> +
> +		ret = cio2_bridge_reprobe_sensor(sensor, i);
> +		if (ret)
> +			goto err_free_swnodes;

> +		pr_info("cio2-bridge: Found supported device %s\n",
> +			supported_devices[i].hid);

Use dev_*() [dev_info()] instead of pr_*() ones.

> +		bridge.n_sensors++;
> +		continue;
> +cont_free_dev:
> +		put_device(dev);
> +		continue;

> +err_free_swnodes:
> +		for (j = 4; j >= 0; j--)
> +			software_node_unregister(&sensor->swnodes[j]);

See above.

> +err_free_fwnode:
> +		fwnode_handle_put(sensor->fwnode);
> +err_free_dev:
> +		put_device(dev);
> +err_rollback:
> +		/*
> +		 * If an iteration of this loop results in -EPROBE_DEFER then
> +		 * we need to roll back any sensors that were successfully
> +		 * registered. Any other error and we'll skip that step, as
> +		 * it seems better to have one successfully connected sensor.
> +		 */
> +
> +		if (ret == -EPROBE_DEFER)
> +			cio2_bridge_unregister_sensors();
> +
> +		break;

This is (all err_* labels) invariant to the loop (you break it), so, move out
of the loop...

> +	}
> +
> +	return ret;

...somewhere here.


...

> +	ret = software_node_register(&cio2_hid_node);
> +	if (ret < 0) {

> +		pr_err("cio2-bridge: Failed to register the CIO2 HID node\n");

dev_err() and so on.

> +		goto err_put_cio2;
> +	}

...

> +#define __NO_VERSION__

What is this for?

...

> +#define NODE_SENSOR(_HID, _PROPS)		\
> +	((const struct software_node) {		\
> +		.name = _HID,			\
> +		.properties = _PROPS		\

Leave comma.

> +	})

...

> +#define IPU3_SENSOR(_HID, _CLIENT)		\
> +	{					\
> +		.hid = _HID,			\
> +		.i2c_id = {			\
> +			{_CLIENT, 0},		\

> +			{ },			\

No comma for terminator type of entries.

> +		}				\

Leave comma.

> +	}

...

> +struct ipu3_sensor {
> +	const char hid[20];

Shouldn't be rather 9?

#define ACPI_ID_LEN     9

> +	const struct i2c_device_id i2c_id[2];
> +};

...

> +struct sensor {
> +	char name[20];

I guess it's predefined by I²C ID.

> +	struct device *dev;
> +	struct software_node swnodes[6];
> +	struct property_entry dev_props[3];
> +	struct property_entry ep_props[4];
> +	struct property_entry cio2_props[3];

I'm now wondering why you can't simply put properties directly to here and do
that kcalloc / memcpy() in few functions? I mean to drop those calls and assign
properties directly. You even won't need to memset() and stack for them!

> +	struct fwnode_handle *fwnode;
> +	struct i2c_driver *old_drv;
> +	struct i2c_driver new_drv;
> +};

...

> +} __attribute__((__packed__));

__packed is enough (it's in compiler.h IIRC).

...

>  	struct cio2_device *cio2;
> +	struct fwnode_handle *endpoint;
>  	int r;

Reverse xmas tree order.

...

> +	endpoint = fwnode_graph_get_next_endpoint(pci_dev->dev.fwnode, NULL);

dev_fwnode()

> +	if (!endpoint) {
> +		r = cio2_bridge_build(pci_dev);
> +		if (r)
> +			return r;
> +	}

...

> +#ifdef CONFIG_CIO2_BRIDGE

IS_ENABLED()

> +
> +int cio2_bridge_build(struct pci_dev *cio2);
> +void cio2_bridge_burn(struct pci_dev *cio2);
> +
> +#else
> +
> +int cio2_bridge_build(struct pci_dev *cio2)
> +{
> +	return 0;
> +}

One line.

> +void cio2_bridge_burn(struct pci_dev *cio2)
> +{
> +}

One line.

> +#endif

-- 
With Best Regards,
Andy Shevchenko

Re: [RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows

[Andy Shevchenko]

On Thu, Oct 01, 2020 at 10:33:26AM +0100, Daniel Scally wrote:

...

> This patch is dependent on another (which implements the software node graph
> family of functions):
> 
> https://lore.kernel.org/linux-media/20200915232827.3416-1-djrscally@gmail.com/

More thoughts about the (future) series. Can you rather do a series of patches
to understand what is going on here. I see something like this:
  patch 1. Add unregister_nodes_reverse()
	2. Use above in test_printf.c
	3. Add that graph support patch
	4. Add T: to MAINTAINERS for IPU3-CIO2
	5. Add this patch

-- 
With Best Regards,
Andy Shevchenko

Re: [RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows

[Dan Scally]

Hi Andy - sorry for delayed reply, busy week

On 01/10/2020 18:37, Andy Shevchenko wrote:
> On Thu, Oct 01, 2020 at 10:33:26AM +0100, Daniel Scally wrote:
>
> Awesome work!
> My, almost minor, comments below.
Thanks as always for your help - great comments. I'll work through and
make the changes you suggest to this code and also...
>> * Built against media_tree instead of linus's tree - there's no T: entry in
>> maintainers for the ipu3-cio2 driver but I see there're recent changes in 
>> media_tree so thought this was the better option.
> Make sense to include T: entry as well (maybe as a separate patch).

...I agree with your other email re. turning this into a series and
making the additional changes you suggested, so I'll do that too for the v3.


Just a couple comments / queries:

>> +// SPDX-License-Identifier: GPL-2.0
> Author line perhaps?

You mean literally just like /* Authored By: Dan Scally */ or something?
OK, no problem.

>> +static const struct ipu3_sensor supported_devices[] = {
>> +	IPU3_SENSOR("INT33BE", "INT33BE:00"),
>> +	IPU3_SENSOR("OVTI2680", "OVTI2680:00"),
>> +	IPU3_SENSOR("OVTI5648", "OVTI5648:00")
> In such cases please leave comma at the last item as well. Easier to extend w/o
> an additional churn.
>
> On top of that, please avoid putting *instance* names, i.e. the second
> parameters in your macro call. What code should do is to take _HID (first
> parameter) and call acpi_dev_match_first_dev() or so.
Yeah I was originally using the i2c_client's name field (this comes into
play during cio2_bridge_reprobe_sensor()) but the matching refused to
work using anything but a string literal. Let me take another look at
this then.
>> +static struct software_node cio2_hid_node = { CIO2_HID, };
> Here, nevertheless, comma can be removed, since update will need to change
> entire line anyway.
Trailing commas where lists can be extended, otherwise none - got it.
>> +static int read_acpi_block(struct device *dev, char *id, void *data, u32 size)
>> +{
>> +	union acpi_object *obj;
>> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	struct acpi_handle *handle = ACPI_HANDLE(dev);
>> +	acpi_status status;
>> +	int ret;
>> +
>> +	status = acpi_evaluate_object(handle, id, NULL, &buffer);
>> +	if (ACPI_FAILURE(status))
>> +		return -ENODEV;
>> +
>> +	obj = buffer.pointer;
>> +	if (!obj || obj->type != ACPI_TYPE_BUFFER) {
> !obj case doesn't require freeing and I would say the error message can be
> amended in such case.
Oops - you suggested that in the last version too and I missed it, sorry
about that. I'll split those two failure modes out.
>> +		for (j = 4; j >= 0; j--)
>> +			software_node_unregister(&sensor->swnodes[j]);
> Seems we may need a simple helper for this (test_printf.c has similar case),
> so, what about do it here for now and probably then move to somewhere like
> swnode.h or whatever holds it.
>
> static inline software_node_unregister_nodes_reverse(const struct software_node *nodes)
> {
> 	unsigned int i = 0;
>
> 	while (nodes[i].name)
> 		i++;
> 	while (i--)
> 		software_node_unregister(&nodes[i]);
> }
Yeah this is a good idea; I see you suggest a new patch for it in your
other email; I'll do a series in the future and add this to the swnode
source file at the same time as doing the changes that you, Heikki and
Sakari suggested for the other patch.
>> +#define __NO_VERSION__
> What is this for?

Somehow I got on the outdated page for compiling modules spanning
multiple files in the linux kernel module programming guide; it's
suggested there but not in the newer version. I shall remove it.

>> +	struct device *dev;
>> +	struct software_node swnodes[6];
>> +	struct property_entry dev_props[3];
>> +	struct property_entry ep_props[4];
>> +	struct property_entry cio2_props[3];
> I'm now wondering why you can't simply put properties directly to here and do
> that kcalloc / memcpy() in few functions? I mean to drop those calls and assign
> properties directly. You even won't need to memset() and stack for them!
I thought you were hinting that I should use kcalloc in the comments
from the last patch to get an array of zero valued entries but I guess I
misunderstood - I can just memset these arrays to 0 and assign all but
the last entry directly and that seems to work fine, so I'll switch to that.
>>  	struct cio2_device *cio2;
>> +	struct fwnode_handle *endpoint;
>>  	int r;
> Reverse xmas tree order.
TIL - thanks, I'll do a pass over the rest of it and make sure that I
follow that everywhere else too
>> +	endpoint = fwnode_graph_get_next_endpoint(pci_dev->dev.fwnode, NULL);
> dev_fwnode()
I avoided that thinking there might be a case where a CIO2 device has a
fwnode but not endpoints defined for some reason, but I'm not familiar
enough to judge whether that situation will ever occur - if it's safe to
do it that way then I'll switch it over.

Re: [RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows

[Andy Shevchenko]

On Thu, Oct 08, 2020 at 10:51:46PM +0100, Dan Scally wrote:
> On 01/10/2020 18:37, Andy Shevchenko wrote:
> > On Thu, Oct 01, 2020 at 10:33:26AM +0100, Daniel Scally wrote:

> > Awesome work!
> > My, almost minor, comments below.
> Thanks as always for your help - great comments. I'll work through and
> make the changes you suggest to this code and also...
> >> * Built against media_tree instead of linus's tree - there's no T: entry in
> >> maintainers for the ipu3-cio2 driver but I see there're recent changes in 
> >> media_tree so thought this was the better option.
> > Make sense to include T: entry as well (maybe as a separate patch).
> 
> ...I agree with your other email re. turning this into a series and
> making the additional changes you suggested, so I'll do that too for the v3.

I forgot to mention module rename as a separate patch. So, something like 6
(or more) in a series I would expect.

...

> >> +// SPDX-License-Identifier: GPL-2.0
> > Author line perhaps?
> 
> You mean literally just like /* Authored By: Dan Scally */ or something?
> OK, no problem.

* Author: Dan Scally <foo@bar.com>

...

> >> +static const struct ipu3_sensor supported_devices[] = {
> >> +	IPU3_SENSOR("INT33BE", "INT33BE:00"),
> >> +	IPU3_SENSOR("OVTI2680", "OVTI2680:00"),
> >> +	IPU3_SENSOR("OVTI5648", "OVTI5648:00")
> > In such cases please leave comma at the last item as well. Easier to extend w/o
> > an additional churn.
> >
> > On top of that, please avoid putting *instance* names, i.e. the second
> > parameters in your macro call. What code should do is to take _HID (first
> > parameter) and call acpi_dev_match_first_dev() or so.
> Yeah I was originally using the i2c_client's name field (this comes into
> play during cio2_bridge_reprobe_sensor()) but the matching refused to
> work using anything but a string literal. Let me take another look at
> this then.

I meant that you get an instance name from the first found device, like

	char instance_name[I2C...];

	adev = first_match_dev();
	if (adev) {
		snprintf(instance_name, ..., acpi_dev_name(adev));
		...
	} else {
		...
	}

...

> >> +static struct software_node cio2_hid_node = { CIO2_HID, };
> > Here, nevertheless, comma can be removed, since update will need to change
> > entire line anyway.
> Trailing commas where lists can be extended, otherwise none - got it.

Just use a common sense. Simple extrapolate it to the next change, if any,
among the same lines.

...

> >> +		for (j = 4; j >= 0; j--)
> >> +			software_node_unregister(&sensor->swnodes[j]);
> > Seems we may need a simple helper for this (test_printf.c has similar case),
> > so, what about do it here for now and probably then move to somewhere like
> > swnode.h or whatever holds it.
> >
> > static inline software_node_unregister_nodes_reverse(const struct software_node *nodes)
> > {
> > 	unsigned int i = 0;
> >
> > 	while (nodes[i].name)
> > 		i++;
> > 	while (i--)
> > 		software_node_unregister(&nodes[i]);
> > }
> Yeah this is a good idea; I see you suggest a new patch for it in your
> other email; I'll do a series in the future and add this to the swnode
> source file at the same time as doing the changes that you, Heikki and
> Sakari suggested for the other patch.

Yes, thanks!

...

> >> +	struct software_node swnodes[6];
> >> +	struct property_entry dev_props[3];
> >> +	struct property_entry ep_props[4];
> >> +	struct property_entry cio2_props[3];
> > I'm now wondering why you can't simply put properties directly to here and do
> > that kcalloc / memcpy() in few functions? I mean to drop those calls and assign
> > properties directly. You even won't need to memset() and stack for them!
> I thought you were hinting that I should use kcalloc in the comments
> from the last patch to get an array of zero valued entries but I guess I
> misunderstood - I can just memset these arrays to 0 and assign all but
> the last entry directly and that seems to work fine, so I'll switch to that.

The idea behind that any kcalloc() or kzalloc() against a container (whatever
data structure that has those property arrays) will do it for you. So, I think
neither kcalloc() nor stack is needed. Instantiate properties directly in the
arrays of sensor data structure.

...

> >> +	endpoint = fwnode_graph_get_next_endpoint(pci_dev->dev.fwnode, NULL);
> > dev_fwnode()
> I avoided that thinking there might be a case where a CIO2 device has a
> fwnode but not endpoints defined for some reason, but I'm not familiar
> enough to judge whether that situation will ever occur - if it's safe to
> do it that way then I'll switch it over.

I meant
	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(&pci_dev->dev), NULL);


-- 
With Best Regards,
Andy Shevchenko

Re: [RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows

[Dan Scally]

On 09/10/2020 13:44, Andy Shevchenko wrote:
>> ...I agree with your other email re. turning this into a series and
>> making the additional changes you suggested, so I'll do that too for the v3.
> I forgot to mention module rename as a separate patch. So, something like 6
> (or more) in a series I would expect.

Yeah no problem, I'll do that too.

>
>>>> +// SPDX-License-Identifier: GPL-2.0
>>> Author line perhaps?
>> You mean literally just like /* Authored By: Dan Scally */ or something?
>> OK, no problem.
> * Author: Dan Scally <foo@bar.com>

Okedokey

>>>> +static const struct ipu3_sensor supported_devices[] = {
>>>> +	IPU3_SENSOR("INT33BE", "INT33BE:00"),
>>>> +	IPU3_SENSOR("OVTI2680", "OVTI2680:00"),
>>>> +	IPU3_SENSOR("OVTI5648", "OVTI5648:00")
>>> In such cases please leave comma at the last item as well. Easier to extend w/o
>>> an additional churn.
>>>
>>> On top of that, please avoid putting *instance* names, i.e. the second
>>> parameters in your macro call. What code should do is to take _HID (first
>>> parameter) and call acpi_dev_match_first_dev() or so.
>> Yeah I was originally using the i2c_client's name field (this comes into
>> play during cio2_bridge_reprobe_sensor()) but the matching refused to
>> work using anything but a string literal. Let me take another look at
>> this then.
> I meant that you get an instance name from the first found device, like
>
> 	char instance_name[I2C...];
>
> 	adev = first_match_dev();
> 	if (adev) {
> 		snprintf(instance_name, ..., acpi_dev_name(adev));
> 		...
> 	} else {
> 		...
> 	}
Ah, yes, this is better than messing around getting the i2c_client - thanks
>> I thought you were hinting that I should use kcalloc in the comments
>> from the last patch to get an array of zero valued entries but I guess I
>> misunderstood - I can just memset these arrays to 0 and assign all but
>> the last entry directly and that seems to work fine, so I'll switch to that.
> The idea behind that any kcalloc() or kzalloc() against a container (whatever
> data structure that has those property arrays) will do it for you. So, I think
> neither kcalloc() nor stack is needed. Instantiate properties directly in the
> arrays of sensor data structure.
Will do
>>>> +	endpoint = fwnode_graph_get_next_endpoint(pci_dev->dev.fwnode, NULL);
>>> dev_fwnode()
>> I avoided that thinking there might be a case where a CIO2 device has a
>> fwnode but not endpoints defined for some reason, but I'm not familiar
>> enough to judge whether that situation will ever occur - if it's safe to
>> do it that way then I'll switch it over.
> I meant
> 	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(&pci_dev->dev), NULL);
Ah! Of course, I'll make that change too, thanks