Commit 27d58498 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Tzung-Bi Shih
Browse files

platform/chrome: wilco_ec: event: Convert to a platform driver 

In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware.  Accordingly, a struct platform_driver should be
used by driver code to bind to that device.  There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the ChromeOS Wilco Embedded Controller event
ACPI driver to a platform one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/

 [1]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/9600287.CDJkKcVGEf@rafael.j.wysocki


Signed-off-by: default avatarTzung-Bi Shih <tzungbi@kernel.org>
parent 25a06b7a

drivers/platform/chrome/wilco_ec/event.c

+34 −32
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <linux/io.h>

#include <linux/list.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/poll.h>

#include <linux/spinlock.h>

#include <linux/uaccess.h>
@@ -198,7 +199,7 @@ struct event_device_data { 


/**

 * enqueue_events() - Place EC events in queue to be read by userspace.

 * @adev: Device the events came from.

 * @dev: Device the events came from.

 * @buf: Buffer of event data.

 * @length: Length of event data buffer.

 *
@@ -209,9 +210,9 @@ struct event_device_data { 
 *

 * Return: 0 on success or negative error code on failure.

 */

static int enqueue_events(struct acpi_device *adev, const u8 *buf, u32 length)

static int enqueue_events(struct device *dev, const u8 *buf, u32 length)

{

	struct event_device_data *dev_data = adev->driver_data;

	struct event_device_data *dev_data = dev_get_drvdata(dev);

	struct ec_event *event, *queue_event, *old_event;

	size_t num_words, event_size;

	u32 offset = 0;
@@ -222,14 +223,14 @@ static int enqueue_events(struct acpi_device *adev, const u8 *buf, u32 length) 
		num_words = ec_event_num_words(event);

		event_size = ec_event_size(event);

		if (num_words > EC_ACPI_MAX_EVENT_WORDS) {

			dev_err(&adev->dev, "Too many event words: %zu > %d\n",

			dev_err(dev, "Too many event words: %zu > %d\n",

				num_words, EC_ACPI_MAX_EVENT_WORDS);

			return -EOVERFLOW;

		}



		/* Ensure event does not overflow the available buffer */

		if ((offset + event_size) > length) {

			dev_err(&adev->dev, "Event exceeds buffer: %zu > %d\n",

			dev_err(dev, "Event exceeds buffer: %zu > %d\n",

				offset + event_size, length);

			return -EOVERFLOW;

		}
@@ -262,12 +263,13 @@ static int enqueue_events(struct acpi_device *adev, const u8 *buf, u32 length) 
static void event_device_notify(acpi_handle handle, u32 value, void *data)

{

	struct acpi_buffer event_buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	struct acpi_device *adev = data;

	struct device *dev = data;

	struct acpi_device *adev = ACPI_COMPANION(dev);

	union acpi_object *obj;

	acpi_status status;



	if (value != EC_ACPI_NOTIFY_EVENT) {

		dev_err(&adev->dev, "Invalid event: 0x%08x\n", value);

		dev_err(dev, "Invalid event: 0x%08x\n", value);

		return;

	}
@@ -275,31 +277,31 @@ static void event_device_notify(acpi_handle handle, u32 value, void *data) 
	status = acpi_evaluate_object(adev->handle, EC_ACPI_GET_EVENT,

				      NULL, &event_buffer);

	if (ACPI_FAILURE(status)) {

		dev_err(&adev->dev, "Error executing ACPI method %s()\n",

		dev_err(dev, "Error executing ACPI method %s()\n",

			EC_ACPI_GET_EVENT);

		return;

	}



	obj = (union acpi_object *)event_buffer.pointer;

	if (!obj) {

		dev_err(&adev->dev, "Nothing returned from %s()\n",

		dev_err(dev, "Nothing returned from %s()\n",

			EC_ACPI_GET_EVENT);

		return;

	}

	if (obj->type != ACPI_TYPE_BUFFER) {

		dev_err(&adev->dev, "Invalid object returned from %s()\n",

		dev_err(dev, "Invalid object returned from %s()\n",

			EC_ACPI_GET_EVENT);

		kfree(obj);

		return;

	}

	if (obj->buffer.length < sizeof(struct ec_event)) {

		dev_err(&adev->dev, "Invalid buffer length %d from %s()\n",

		dev_err(dev, "Invalid buffer length %d from %s()\n",

			obj->buffer.length, EC_ACPI_GET_EVENT);

		kfree(obj);

		return;

	}



	enqueue_events(adev, obj->buffer.pointer, obj->buffer.length);

	enqueue_events(dev, obj->buffer.pointer, obj->buffer.length);

	kfree(obj);

}
@@ -434,8 +436,8 @@ static void hangup_device(struct event_device_data *dev_data) 
}



/**

 * event_device_add() - Callback when creating a new device.

 * @adev: ACPI device that we will be receiving events from.

 * event_device_probe() - Callback when creating a new device.

 * @pdev: Platform device that we will be receiving events from.

 *

 * This finds a free minor number for the device, allocates and initializes

 * some device data, and creates a new device and char dev node.
@@ -447,7 +449,7 @@ static void hangup_device(struct event_device_data *dev_data) 
 *

 * Return: 0 on success, negative error code on failure.

 */

static int event_device_add(struct acpi_device *adev)

static int event_device_probe(struct platform_device *pdev)

{

	struct event_device_data *dev_data;

	int error, minor;
@@ -455,7 +457,7 @@ static int event_device_add(struct acpi_device *adev) 
	minor = ida_alloc_max(&event_ida, EVENT_MAX_DEV-1, GFP_KERNEL);

	if (minor < 0) {

		error = minor;

		dev_err(&adev->dev, "Failed to find minor number: %d\n", error);

		dev_err(&pdev->dev, "Failed to find minor number: %d\n", error);

		return error;

	}
@@ -466,7 +468,7 @@ static int event_device_add(struct acpi_device *adev) 
	}



	/* Initialize the device data. */

	adev->driver_data = dev_data;

	platform_set_drvdata(pdev, dev_data);

	dev_data->events = event_queue_new(queue_size);

	if (!dev_data->events) {

		kfree(dev_data);
@@ -492,8 +494,9 @@ static int event_device_add(struct acpi_device *adev) 
		goto free_dev_data;



	/* Install an ACPI notify handler. */

	error = acpi_dev_install_notify_handler(adev, ACPI_DEVICE_NOTIFY,

						event_device_notify, adev);

	error = acpi_dev_install_notify_handler(ACPI_COMPANION(&pdev->dev),

						ACPI_DEVICE_NOTIFY,

						event_device_notify, &pdev->dev);

	if (error)

		goto free_cdev;
@@ -508,12 +511,12 @@ static int event_device_add(struct acpi_device *adev) 
	return error;

}



static void event_device_remove(struct acpi_device *adev)

static void event_device_remove(struct platform_device *pdev)

{

	struct event_device_data *dev_data = adev->driver_data;

	struct event_device_data *dev_data = platform_get_drvdata(pdev);



	acpi_dev_remove_notify_handler(adev, ACPI_DEVICE_NOTIFY,

				       event_device_notify);

	acpi_dev_remove_notify_handler(ACPI_COMPANION(&pdev->dev),

				       ACPI_DEVICE_NOTIFY, event_device_notify);

	cdev_device_del(&dev_data->cdev, &dev_data->dev);

	ida_free(&event_ida, MINOR(dev_data->dev.devt));

	hangup_device(dev_data);
@@ -525,13 +528,12 @@ static const struct acpi_device_id event_acpi_ids[] = { 
};

MODULE_DEVICE_TABLE(acpi, event_acpi_ids);



static struct acpi_driver event_driver = {

	.name = DRV_NAME,

	.class = DRV_NAME,

	.ids = event_acpi_ids,

	.ops = {

		.add = event_device_add,

static struct platform_driver event_driver = {

	.probe = event_device_probe,

	.remove = event_device_remove,

	.driver = {

		.name = DRV_NAME,

		.acpi_match_table = event_acpi_ids,

	},

};
@@ -554,7 +556,7 @@ static int __init event_module_init(void) 
	}

	event_major = MAJOR(dev_num);



	ret = acpi_bus_register_driver(&event_driver);

	ret = platform_driver_register(&event_driver);

	if (ret < 0) {

		pr_err(DRV_NAME ": Failed registering driver: %d\n", ret);

		goto unregister_region;
@@ -572,7 +574,7 @@ static int __init event_module_init(void) 


static void __exit event_module_exit(void)

{

	acpi_bus_unregister_driver(&event_driver);

	platform_driver_unregister(&event_driver);

	unregister_chrdev_region(MKDEV(event_major, 0), EVENT_MAX_DEV);

	class_unregister(&event_class);

	ida_destroy(&event_ida);