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Commit f5808ac1 authored by Andrew Jeffery's avatar Andrew Jeffery Committed by Jacek Anaszewski
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leds: gpio: Allow LED to retain state at shutdown 



In some systems, such as Baseboard Management Controllers (BMCs), we
want to retain the state of LEDs across a reboot of the BMC (whilst the
host remains up). Implement support for the retain-state-shutdown
devicetree property in leds-gpio.

Signed-off-by: default avatarAndrew Jeffery <andrew@aj.id.au>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Tested-by: default avatarBrandon Wyman <bjwyman@gmail.com>
Signed-off-by: default avatarJacek Anaszewski <jacek.anaszewski@gmail.com>
parent 0f34f958

drivers/leds/leds-gpio.c

+6 −1
Original line number Diff line number Diff line
@@ -134,6 +134,8 @@ static int create_gpio_led(const struct gpio_led *template, 
		led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;

	if (template->panic_indicator)

		led_dat->cdev.flags |= LED_PANIC_INDICATOR;

	if (template->retain_state_shutdown)

		led_dat->cdev.flags |= LED_RETAIN_AT_SHUTDOWN;



	ret = gpiod_direction_output(led_dat->gpiod, state);

	if (ret < 0)
@@ -205,6 +207,8 @@ static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev) 


		if (fwnode_property_present(child, "retain-state-suspended"))

			led.retain_state_suspended = 1;

		if (fwnode_property_present(child, "retain-state-shutdown"))

			led.retain_state_shutdown = 1;

		if (fwnode_property_present(child, "panic-indicator"))

			led.panic_indicator = 1;
@@ -267,6 +271,7 @@ static void gpio_led_shutdown(struct platform_device *pdev) 
	for (i = 0; i < priv->num_leds; i++) {

		struct gpio_led_data *led = &priv->leds[i];



		if (!(led->cdev.flags & LED_RETAIN_AT_SHUTDOWN))

			gpio_led_set(&led->cdev, LED_OFF);

	}

}

include/linux/leds.h

+2 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ struct led_classdev { 
#define LED_HW_PLUGGABLE	(1 << 19)

#define LED_PANIC_INDICATOR	(1 << 20)

#define LED_BRIGHT_HW_CHANGED	(1 << 21)

#define LED_RETAIN_AT_SHUTDOWN	(1 << 22)



	/* set_brightness_work / blink_timer flags, atomic, private. */

	unsigned long		work_flags;
@@ -392,6 +393,7 @@ struct gpio_led { 
	unsigned	retain_state_suspended : 1;

	unsigned	panic_indicator : 1;

	unsigned	default_state : 2;

	unsigned	retain_state_shutdown : 1;

	/* default_state should be one of LEDS_GPIO_DEFSTATE_(ON|OFF|KEEP) */

	struct gpio_desc *gpiod;

};