[PATCH v1 1/2] hid-asus: use hid for brightness control on keyboard

["Luke D. Jones" <luke@ljones.dev>]

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>
---
 drivers/hid/hid-asus.c                     |  6 ++++
 drivers/platform/x86/asus-wmi.c            | 35 +++++++++++++++++++++-
 include/linux/platform_data/x86/asus-wmi.h | 10 +++++++
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index 02de2bf4f790..4cba8e143031 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -492,12 +492,18 @@ 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 && asus_use_hid_led()) {
+		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);
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 3f9b6285c9a6..54cb07c79fcf 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -144,6 +144,15 @@ module_param(fnlock_default, bool, 0444);
 
 static const char * const ashs_ids[] = { "ATK4001", "ATK4002", NULL };
 
+static const char * const use_hid_led_matches[] = {
+	"ROG Zephyrus",
+	"ROG Strix",
+	"ROG Flow",
+	"GA403",
+	"GU605",
+	"RC71L",
+};
+
 static int throttle_thermal_policy_write(struct asus_wmi *);
 
 static bool ashs_present(void)
@@ -1642,6 +1651,29 @@ static int micmute_led_set(struct led_classdev *led_cdev,
 	return err < 0 ? err : 0;
 }
 
+bool asus_use_hid_led(void)
+{
+	const char *product, *board;
+	int i;
+
+	product = dmi_get_system_info(DMI_PRODUCT_FAMILY);
+	if (!product)
+		return false;
+
+	board = dmi_get_system_info(DMI_BOARD_NAME);
+	if (!board)
+		return false;
+
+	for (i = 0; i < ARRAY_SIZE(use_hid_led_matches); i++) {
+		if (strstr(product, use_hid_led_matches[i]))
+			return true;
+		if (strstr(board, use_hid_led_matches[i]))
+			return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(asus_use_hid_led);
+
 static void asus_wmi_led_exit(struct asus_wmi *asus)
 {
 	led_classdev_unregister(&asus->kbd_led);
@@ -1681,7 +1713,8 @@ 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) && !asus_use_hid_led()) {
+		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;
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 3eb5cd6773ad..6833035f7006 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -160,4 +160,14 @@ 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 */
+#if IS_ENABLED(CONFIG_ASUS_WMI)
+bool asus_use_hid_led(void);
+#else
+static inline bool asus_use_hid_led(void)
+{
+	return true;
+}
+#endif
+
 #endif	/* __PLATFORM_DATA_X86_ASUS_WMI_H */
-- 
2.45.1