leds: pwm: Add optional DT property default-brightness

When probing if default LED state is on then default brightness will be
applied instead of max brightness.

Signed-off-by: George Stark <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/leds/leds-pwm.c

···
 	return pwm_apply_might_sleep(led_dat->pwm, &led_dat->pwmstate);
 }
 
+static int led_pwm_default_brightness_get(struct fwnode_handle *fwnode,
+					  int max_brightness)
+{
+	unsigned int default_brightness;
+	int ret;
+
+	ret = fwnode_property_read_u32(fwnode, "default-brightness",
+				       &default_brightness);
+	if (ret < 0 || default_brightness > max_brightness)
+		default_brightness = max_brightness;
+
+	return default_brightness;
+}
+
 __attribute__((nonnull))
 static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
 		       struct led_pwm *led, struct fwnode_handle *fwnode)
···
 	/* set brightness */
 	switch (led->default_state) {
 	case LEDS_DEFSTATE_ON:
-		led_data->cdev.brightness = led->max_brightness;
+		led_data->cdev.brightness =
+			led_pwm_default_brightness_get(fwnode, led->max_brightness);
 		break;
 	case LEDS_DEFSTATE_KEEP:
 		{