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leds: gpio: Allow LED to retain state at shutdown

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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: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Brandon Wyman <bjwyman@gmail.com>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
This commit is contained in:
Andrew Jeffery 2017-08-28 09:47:11 +09:30 committed by Jacek Anaszewski
parent 0f34f95876
commit f5808ac158
2 changed files with 8 additions and 1 deletions
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7
drivers/leds/leds-gpio.c
View file

@ -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;
@ -267,7 +271,8 @@ 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];
gpio_led_set(&led->cdev, LED_OFF);
if (!(led->cdev.flags & LED_RETAIN_AT_SHUTDOWN))
gpio_led_set(&led->cdev, LED_OFF);
}
}

2
include/linux/leds.h
View file

@ -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;
};