[PATCH v3 1/2] platform/x86: uniwill-laptop: Fix brightness notify for 3 level keyboards

[Werner Sembach <wse@tuxedocomputers.com>]

The devices with 3 brightness level keyboards send
UNIWILL_OSD_KB_LED_LEVEL0, UNIWILL_OSD_KB_LED_LEVEL2, and
UNIWILL_OSD_KB_LED_LEVEL4 and not UNIWILL_OSD_KB_LED_LEVEL0,
UNIWILL_OSD_KB_LED_LEVEL1, and UNIWILL_OSD_KB_LED_LEVEL2.

This patch maps the events correctly to brightness levels 0, 1, and 2.

Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
---
V1->V2: Use the events as source of truth for brightness_hw_changed value
        again to avoid a race condition as Armin had pointed out.
V2->V3: Return error for unexpected brightness level count.

 drivers/platform/x86/uniwill/uniwill-acpi.c | 26 +++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/platform/x86/uniwill/uniwill-acpi.c b/drivers/platform/x86/uniwill/uniwill-acpi.c
index 7a2eeaec4c961..5df3611919ce3 100644
--- a/drivers/platform/x86/uniwill/uniwill-acpi.c
+++ b/drivers/platform/x86/uniwill/uniwill-acpi.c
@@ -1631,6 +1631,32 @@ static int uniwill_notify_kbd_led(struct uniwill_data *data, int brightness)
 	struct led_classdev *led_cdev;
 	int ret;
 
+	/*
+	 * The devices with 3 brightness level keyboards send
+	 * UNIWILL_OSD_KB_LED_LEVEL0, UNIWILL_OSD_KB_LED_LEVEL2, and
+	 * UNIWILL_OSD_KB_LED_LEVEL4 which need to be mapped to 0, 1, and 2.
+	 */
+	switch (data->kbd_led_max_brightness) {
+	case 4:
+		break;
+	case 2:
+		switch (brightness) {
+		case 0:
+			break;
+		case 2:
+			brightness = 1;
+			break;
+		case 4:
+			brightness = 2;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	if (data->kbd_led_single_color)
 		led_cdev = &data->kbd_led_cdev;
 	else

base-commit: 54745d563114b74f6fecebce68cd020d06c1772b
-- 
2.43.0