openwrt/target/linux/brcm2708/patches-4.1/0123-leds-gpio-Implement-the-brightness_get-method.patch

From 5a3324e4eb8898d293fdc562117877cb313718a1 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Wed, 15 Jul 2015 13:46:08 +0100
Subject: [PATCH 123/203] leds-gpio: Implement the brightness_get method

The power LED uses some clever logic that means it is driven
by a voltage measuring circuit when configured as input, otherwise
it is driven by the GPIO output value. This patch wires up the
brightness_get method for leds-gpio so that user-space can monitor
the LED value via /sys/class/gpio/led1/brightness. Using the input
trigger this returns an indication of the system power health,
otherwise it is just whatever value the trigger has written most
recently.

See: https://github.com/raspberrypi/linux/issues/1064
---
 drivers/leds/leds-gpio.c | 8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/leds/leds-gpio.c
+++ b/drivers/leds/leds-gpio.c
@@ -82,6 +82,13 @@ static void gpio_led_set(struct led_clas
 	}
 }
 
+static enum led_brightness gpio_led_get(struct led_classdev *led_cdev)
+{
+	struct gpio_led_data *led_dat =
+		container_of(led_cdev, struct gpio_led_data, cdev);
+	return gpiod_get_value_cansleep(led_dat->gpiod) ? LED_FULL : LED_OFF;
+}
+
 static int gpio_blink_set(struct led_classdev *led_cdev,
 	unsigned long *delay_on, unsigned long *delay_off)
 {
@@ -138,6 +145,7 @@ static int create_gpio_led(const struct
 		led_dat->cdev.blink_set = gpio_blink_set;
 	}
 	led_dat->cdev.brightness_set = gpio_led_set;
+	led_dat->cdev.brightness_get = gpio_led_get;
 	if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP)
 		state = !!gpiod_get_value_cansleep(led_dat->gpiod);
 	else