From: "Rafael J. Wysocki" <[email protected]> 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 Apple Backlight 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/[email protected]/ [1] Signed-off-by: Rafael J. Wysocki <[email protected]> --- drivers/video/backlight/apple_bl.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/video/backlight/apple_bl.c b/drivers/video/backlight/apple_bl.c index aaa824437a2a..423513d68b5b 100644 --- a/drivers/video/backlight/apple_bl.c +++ b/drivers/video/backlight/apple_bl.c @@ -24,6 +24,7 @@ #include <linux/pci.h> #include <linux/acpi.h> #include <linux/atomic.h> +#include <linux/platform_device.h> #include <acpi/video.h> static struct backlight_device *apple_backlight_device; @@ -134,7 +135,7 @@ static const struct hw_data nvidia_chipset_data = { .set_brightness = nvidia_chipset_set_brightness, }; -static int apple_bl_add(struct acpi_device *dev) +static int apple_bl_probe(struct platform_device *pdev) { struct backlight_properties props; struct pci_dev *host; @@ -193,7 +194,7 @@ static int apple_bl_add(struct acpi_device *dev) return 0; } -static void apple_bl_remove(struct acpi_device *dev) +static void apple_bl_remove(struct platform_device *pdev) { backlight_device_unregister(apple_backlight_device); @@ -206,12 +207,12 @@ static const struct acpi_device_id apple_bl_ids[] = { {"", 0}, }; -static struct acpi_driver apple_bl_driver = { - .name = "Apple backlight", - .ids = apple_bl_ids, - .ops = { - .add = apple_bl_add, - .remove = apple_bl_remove, +static struct platform_driver apple_bl_driver = { + .probe = apple_bl_probe, + .remove = apple_bl_remove, + .driver = { + .name = "Apple backlight", + .acpi_match_table = apple_bl_ids, }, }; @@ -224,12 +225,12 @@ static int __init apple_bl_init(void) if (acpi_video_get_backlight_type() != acpi_backlight_vendor) return -ENODEV; - return acpi_bus_register_driver(&apple_bl_driver); + return platform_driver_register(&apple_bl_driver); } static void __exit apple_bl_exit(void) { - acpi_bus_unregister_driver(&apple_bl_driver); + platform_driver_unregister(&apple_bl_driver); } module_init(apple_bl_init); -- 2.51.0
