From 5a3324e4eb8898d293fdc562117877cb313718a1 Mon Sep 17 00:00:00 2001 From: Phil Elwell 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