platform/x86: x86-android-tablets: Adjust Xiaomi Pad 2 bottom bezel touch buttons LED

The "input-events" LED trigger used to turn on the backlight LEDs had to
be rewritten to use led_trigger_register_simple() + led_trigger_event()
to fix a serious locking issue.

This means it no longer supports using blink_brightness to set a per LED
brightness for the trigger and it no longer sets LED_CORE_SUSPENDRESUME.

Adjust the MiPad 2 bottom bezel touch buttons LED class device to match:

1. Make LED_FULL the maximum brightness to fix the LED brightness
   being very low when on.
2. Set flags = LED_CORE_SUSPENDRESUME.

Signed-off-by: Hans de Goede <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: jwrdegoede

drivers/platform/x86/x86-android-tablets/other.c

@@ -670,7 +670,7 @@ static const struct software_node *ktd2026_node_group[] = {
  * is controlled by the "pwm_soc_lpss_2" PWM output.
  */
 #define XIAOMI_MIPAD2_LED_PERIOD_NS		19200
-#define XIAOMI_MIPAD2_LED_DEFAULT_DUTY		 6000 /* From Android kernel */
+#define XIAOMI_MIPAD2_LED_MAX_DUTY_NS		 6000 /* From Android kernel */
 
 static struct pwm_device *xiaomi_mipad2_led_pwm;
 
@@ -679,7 +679,7 @@ static int xiaomi_mipad2_brightness_set(struct led_classdev *led_cdev,
 {
 	struct pwm_state state = {
 		.period = XIAOMI_MIPAD2_LED_PERIOD_NS,
-		.duty_cycle = val,
+		.duty_cycle = XIAOMI_MIPAD2_LED_MAX_DUTY_NS * val / LED_FULL,
 		/* Always set PWM enabled to avoid the pin floating */
 		.enabled = true,
 	};
@@ -701,11 +701,11 @@ static int __init xiaomi_mipad2_init(struct device *dev)
 		return -ENOMEM;
 
 	led_cdev->name = "mipad2:white:touch-buttons-backlight";
-	led_cdev->max_brightness = XIAOMI_MIPAD2_LED_PERIOD_NS;
-	/* "input-events" trigger uses blink_brightness */
-	led_cdev->blink_brightness = XIAOMI_MIPAD2_LED_DEFAULT_DUTY;
+	led_cdev->max_brightness = LED_FULL;
 	led_cdev->default_trigger = "input-events";
 	led_cdev->brightness_set_blocking = xiaomi_mipad2_brightness_set;
+	/* Turn LED off during suspend */
+	led_cdev->flags = LED_CORE_SUSPENDRESUME;
 
 	ret = devm_led_classdev_register(dev, led_cdev);
 	if (ret)