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

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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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/9600287.CDJkKcVGEf@rafael.j.wysocki
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
This commit is contained in:
Rafael J. Wysocki 2026-03-05 20:46:19 +01:00 committed by Tzung-Bi Shih
parent 25a06b7a32
commit 27d58498f6
1 changed files with 34 additions and 32 deletions
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66
drivers/platform/chrome/wilco_ec/event.c
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@ -38,6 +38,7 @@
#include <linux/io.h> #include <linux/io.h>
#include <linux/list.h> #include <linux/list.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/poll.h> #include <linux/poll.h>
#include <linux/spinlock.h> #include <linux/spinlock.h>
#include <linux/uaccess.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. * 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. * @buf: Buffer of event data.
* @length: Length of event data buffer. * @length: Length of event data buffer.
* *
@ -209,9 +210,9 @@ struct event_device_data {
* *
* Return: 0 on success or negative error code on failure. * 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; struct ec_event *event, *queue_event, *old_event;
size_t num_words, event_size; size_t num_words, event_size;
u32 offset = 0; 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); num_words = ec_event_num_words(event);
event_size = ec_event_size(event); event_size = ec_event_size(event);
if (num_words > EC_ACPI_MAX_EVENT_WORDS) { 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); num_words, EC_ACPI_MAX_EVENT_WORDS);
return -EOVERFLOW; return -EOVERFLOW;
} }
/* Ensure event does not overflow the available buffer */ /* Ensure event does not overflow the available buffer */
if ((offset + event_size) > length) { 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); offset + event_size, length);
return -EOVERFLOW; 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) static void event_device_notify(acpi_handle handle, u32 value, void *data)
{ {
struct acpi_buffer event_buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 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; union acpi_object *obj;
acpi_status status; acpi_status status;
if (value != EC_ACPI_NOTIFY_EVENT) { 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; 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, status = acpi_evaluate_object(adev->handle, EC_ACPI_GET_EVENT,
NULL, &event_buffer); NULL, &event_buffer);
if (ACPI_FAILURE(status)) { 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); EC_ACPI_GET_EVENT);
return; return;
} }
obj = (union acpi_object *)event_buffer.pointer; obj = (union acpi_object *)event_buffer.pointer;
if (!obj) { if (!obj) {
dev_err(&adev->dev, "Nothing returned from %s()\n", dev_err(dev, "Nothing returned from %s()\n",
EC_ACPI_GET_EVENT); EC_ACPI_GET_EVENT);
return; return;
} }
if (obj->type != ACPI_TYPE_BUFFER) { 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); EC_ACPI_GET_EVENT);
kfree(obj); kfree(obj);
return; return;
} }
if (obj->buffer.length < sizeof(struct ec_event)) { 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); obj->buffer.length, EC_ACPI_GET_EVENT);
kfree(obj); kfree(obj);
return; return;
} }
enqueue_events(adev, obj->buffer.pointer, obj->buffer.length); enqueue_events(dev, obj->buffer.pointer, obj->buffer.length);
kfree(obj); 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. * event_device_probe() - Callback when creating a new device.
* @adev: ACPI device that we will be receiving events from. * @pdev: Platform device that we will be receiving events from.
* *
* This finds a free minor number for the device, allocates and initializes * This finds a free minor number for the device, allocates and initializes
* some device data, and creates a new device and char dev node. * 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. * 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; struct event_device_data *dev_data;
int error, minor; 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); minor = ida_alloc_max(&event_ida, EVENT_MAX_DEV-1, GFP_KERNEL);
if (minor < 0) { if (minor < 0) {
error = minor; 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; return error;
} }
@ -466,7 +468,7 @@ static int event_device_add(struct acpi_device *adev)
} }
/* Initialize the device data. */ /* Initialize the device data. */
adev->driver_data = dev_data; platform_set_drvdata(pdev, dev_data);
dev_data->events = event_queue_new(queue_size); dev_data->events = event_queue_new(queue_size);
if (!dev_data->events) { if (!dev_data->events) {
kfree(dev_data); kfree(dev_data);
@ -492,8 +494,9 @@ static int event_device_add(struct acpi_device *adev)
goto free_dev_data; goto free_dev_data;
/* Install an ACPI notify handler. */ /* Install an ACPI notify handler. */
error = acpi_dev_install_notify_handler(adev, ACPI_DEVICE_NOTIFY, error = acpi_dev_install_notify_handler(ACPI_COMPANION(&pdev->dev),
event_device_notify, adev); ACPI_DEVICE_NOTIFY,
event_device_notify, &pdev->dev);
if (error) if (error)
goto free_cdev; goto free_cdev;
@ -508,12 +511,12 @@ static int event_device_add(struct acpi_device *adev)
return error; 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, acpi_dev_remove_notify_handler(ACPI_COMPANION(&pdev->dev),
event_device_notify); ACPI_DEVICE_NOTIFY, event_device_notify);
cdev_device_del(&dev_data->cdev, &dev_data->dev); cdev_device_del(&dev_data->cdev, &dev_data->dev);
ida_free(&event_ida, MINOR(dev_data->dev.devt)); ida_free(&event_ida, MINOR(dev_data->dev.devt));
hangup_device(dev_data); hangup_device(dev_data);
@ -525,13 +528,12 @@ static const struct acpi_device_id event_acpi_ids[] = {
}; };
MODULE_DEVICE_TABLE(acpi, event_acpi_ids); MODULE_DEVICE_TABLE(acpi, event_acpi_ids);
static struct acpi_driver event_driver = { static struct platform_driver event_driver = {
.name = DRV_NAME, .probe = event_device_probe,
.class = DRV_NAME, .remove = event_device_remove,
.ids = event_acpi_ids, .driver = {
.ops = { .name = DRV_NAME,
.add = event_device_add, .acpi_match_table = event_acpi_ids,
.remove = event_device_remove,
}, },
}; };
@ -554,7 +556,7 @@ static int __init event_module_init(void)
} }
event_major = MAJOR(dev_num); event_major = MAJOR(dev_num);
ret = acpi_bus_register_driver(&event_driver); ret = platform_driver_register(&event_driver);
if (ret < 0) { if (ret < 0) {
pr_err(DRV_NAME ": Failed registering driver: %d\n", ret); pr_err(DRV_NAME ": Failed registering driver: %d\n", ret);
goto unregister_region; goto unregister_region;
@ -572,7 +574,7 @@ static int __init event_module_init(void)
static void __exit event_module_exit(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); unregister_chrdev_region(MKDEV(event_major, 0), EVENT_MAX_DEV);
class_unregister(&event_class); class_unregister(&event_class);
ida_destroy(&event_ida); ida_destroy(&event_ida);