backlight: apple_bl: 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 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/2396510.ElGaqSPkdT@rafael.j.wysocki/
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org>
Link: https://patch.msgid.link/5084777.GXAFRqVoOG@rafael.j.wysocki
Signed-off-by: Lee Jones <lee@kernel.org>

diff --git a/drivers/video/backlight/apple_bl.c b/drivers/video/backlight/apple_bl.c
index aaa824437a2ae4d27e8aabe6db042494e8ebcb20..423513d68b5b68910e66c4b0c1cc2eb3752f5e8b 100644 (file)
--- 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);