hid-asus: use hid for brightness control on keyboard

On almost all ASUS ROG series laptops the MCU used for the USB keyboard
also has a HID packet used for setting the brightness. This is usually
the same as the WMI method. But in some laptops the WMI method either
is missing or doesn't work, so we should default to the HID control.
Signed-off-by: Luke D. Jones <luke@ljones.dev>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240713074733.77334-2-luke@ljones.devReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/hid/hid-asus.c

@@ -492,12 +492,19 @@ static void asus_kbd_backlight_work(struct work_struct *work)
  */
 static bool asus_kbd_wmi_led_control_present(struct hid_device *hdev)
 {
+	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
 	u32 value;
 	int ret;
 
 	if (!IS_ENABLED(CONFIG_ASUS_WMI))
 		return false;
 
+	if (drvdata->quirks & QUIRK_ROG_NKEY_KEYBOARD &&
+			dmi_check_system(asus_use_hid_led_dmi_ids)) {
+		hid_info(hdev, "using HID for asus::kbd_backlight\n");
+		return false;
+	}
+
 	ret = asus_wmi_evaluate_method(ASUS_WMI_METHODID_DSTS,
 				       ASUS_WMI_DEVID_KBD_BACKLIGHT, 0, &value);
 	hid_dbg(hdev, "WMI backlight check: rc %d value %x", ret, value);

drivers/platform/x86/asus-wmi.c

@@ -1714,7 +1714,8 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
 			goto error;
 	}
 
-	if (!kbd_led_read(asus, &led_val, NULL)) {
+	if (!kbd_led_read(asus, &led_val, NULL) && !dmi_check_system(asus_use_hid_led_dmi_ids)) {
+		pr_info("using asus-wmi for asus::kbd_backlight\n");
 		asus->kbd_led_wk = led_val;
 		asus->kbd_led.name = "asus::kbd_backlight";
 		asus->kbd_led.flags = LED_BRIGHT_HW_CHANGED;

include/linux/platform_data/x86/asus-wmi.h

@@ -4,6 +4,7 @@
 
 #include <linux/errno.h>
 #include <linux/types.h>
+#include <linux/dmi.h>
 
 /* WMI Methods */
 #define ASUS_WMI_METHODID_SPEC	        0x43455053 /* BIOS SPECification */
@@ -165,4 +166,39 @@ static inline int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1,
 }
 #endif
 
+/* To be used by both hid-asus and asus-wmi to determine which controls kbd_brightness */
+static const struct dmi_system_id asus_use_hid_led_dmi_ids[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "ROG Zephyrus"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "ROG Strix"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "ROG Flow"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_BOARD_NAME, "GA403U"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_BOARD_NAME, "GU605M"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_BOARD_NAME, "RC71L"),
+		},
+	},
+	{ },
+};
+
 #endif	/* __PLATFORM_DATA_X86_ASUS_WMI_H */