From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

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 privacy-screen 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>
---

v1 -> v2: No changes

---
 .../platform/chrome/chromeos_privacy_screen.c | 41 ++++++++-----------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/drivers/platform/chrome/chromeos_privacy_screen.c b/drivers/platform/chrome/chromeos_privacy_screen.c
index bb74ddf9af4a..abc5d189a389 100644
--- a/drivers/platform/chrome/chromeos_privacy_screen.c
+++ b/drivers/platform/chrome/chromeos_privacy_screen.c
@@ -12,6 +12,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/platform_device.h>
 #include <drm/drm_privacy_screen_driver.h>
 
 /*
@@ -32,11 +33,10 @@ chromeos_privacy_screen_get_hw_state(struct drm_privacy_screen
 				     *drm_privacy_screen)
 {
 	union acpi_object *obj;
-	acpi_handle handle;
 	struct device *privacy_screen =
 		drm_privacy_screen_get_drvdata(drm_privacy_screen);
+	acpi_handle handle = ACPI_HANDLE(privacy_screen);
 
-	handle = acpi_device_handle(to_acpi_device(privacy_screen));
 	obj = acpi_evaluate_dsm(handle, &chromeos_privacy_screen_dsm_guid,
 				PRIV_SCRN_DSM_REVID,
 				PRIV_SCRN_DSM_FN_GET_STATUS, NULL);
@@ -65,11 +65,9 @@ chromeos_privacy_screen_set_sw_state(struct drm_privacy_screen
 				     enum drm_privacy_screen_status state)
 {
 	union acpi_object *obj = NULL;
-	acpi_handle handle;
 	struct device *privacy_screen =
 		drm_privacy_screen_get_drvdata(drm_privacy_screen);
-
-	handle = acpi_device_handle(to_acpi_device(privacy_screen));
+	acpi_handle handle = ACPI_HANDLE(privacy_screen);
 
 	if (state == PRIVACY_SCREEN_DISABLED) {
 		obj = acpi_evaluate_dsm(handle,
@@ -104,30 +102,28 @@ static const struct drm_privacy_screen_ops chromeos_privacy_screen_ops = {
 	.set_sw_state = chromeos_privacy_screen_set_sw_state,
 };
 
-static int chromeos_privacy_screen_add(struct acpi_device *adev)
+static int chromeos_privacy_screen_probe(struct platform_device *pdev)
 {
 	struct drm_privacy_screen *drm_privacy_screen =
-		drm_privacy_screen_register(&adev->dev,
+		drm_privacy_screen_register(&pdev->dev,
 					    &chromeos_privacy_screen_ops,
-					    &adev->dev);
+					    &pdev->dev);
 
 	if (IS_ERR(drm_privacy_screen)) {
-		dev_err(&adev->dev, "Error registering privacy-screen\n");
+		dev_err(&pdev->dev, "Error registering privacy-screen\n");
 		return PTR_ERR(drm_privacy_screen);
 	}
 
-	adev->driver_data = drm_privacy_screen;
-	dev_info(&adev->dev, "registered privacy-screen '%s'\n",
+	platform_set_drvdata(pdev, drm_privacy_screen);
+	dev_info(&pdev->dev, "registered privacy-screen '%s'\n",
 		 dev_name(&drm_privacy_screen->dev));
 
 	return 0;
 }
 
-static void chromeos_privacy_screen_remove(struct acpi_device *adev)
+static void chromeos_privacy_screen_remove(struct platform_device *pdev)
 {
-	struct drm_privacy_screen *drm_privacy_screen =	acpi_driver_data(adev);
-
-	drm_privacy_screen_unregister(drm_privacy_screen);
+	drm_privacy_screen_unregister(platform_get_drvdata(pdev));
 }
 
 static const struct acpi_device_id chromeos_privacy_screen_device_ids[] = {
@@ -136,17 +132,16 @@ static const struct acpi_device_id chromeos_privacy_screen_device_ids[] = {
 };
 MODULE_DEVICE_TABLE(acpi, chromeos_privacy_screen_device_ids);
 
-static struct acpi_driver chromeos_privacy_screen_driver = {
-	.name = "chromeos_privacy_screen_driver",
-	.class = "ChromeOS",
-	.ids = chromeos_privacy_screen_device_ids,
-	.ops = {
-		.add = chromeos_privacy_screen_add,
-		.remove = chromeos_privacy_screen_remove,
+static struct platform_driver chromeos_privacy_screen_driver = {
+	.probe = chromeos_privacy_screen_probe,
+	.remove = chromeos_privacy_screen_remove,
+	.driver = {
+		.name = "chromeos_privacy_screen_driver",
+		.acpi_match_table = chromeos_privacy_screen_device_ids,
 	},
 };
 
-module_acpi_driver(chromeos_privacy_screen_driver);
+module_platform_driver(chromeos_privacy_screen_driver);
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("ChromeOS ACPI Privacy Screen driver");
 MODULE_AUTHOR("Rajat Jain <rajatja@google.com>");
-- 
2.51.0