[PATCH 5/5] leds: gpio: Support the panic-blink firmware property

From: Ezequiel Garcia
Date: Mon Apr 04 2016 - 16:22:44 EST


GPIO LEDs are relatively cheap, and so are ideal to blink on
a kernel panic. This commit adds support for the new "panic-blink"
firmware property, allowing to mark a given LED to blink on
a kernel panic.

Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx>
---
drivers/leds/leds-gpio.c | 4 ++++
include/linux/leds.h | 1 +
2 files changed, 5 insertions(+)

diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
index 61143f55597e..74e35dcaf874 100644
--- a/drivers/leds/leds-gpio.c
+++ b/drivers/leds/leds-gpio.c
@@ -127,6 +127,8 @@ static int create_gpio_led(const struct gpio_led *template,
led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
if (!template->retain_state_suspended)
led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
+ if (template->panic_blink)
+ led_dat->cdev.flags |= LED_BLINK_AT_PANIC;

ret = gpiod_direction_output(led_dat->gpiod, state);
if (ret < 0)
@@ -200,6 +202,8 @@ 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, "panic-blink"))
+ led.panic_blink = 1;

ret = create_gpio_led(&led, &priv->leds[priv->num_leds],
dev, NULL);
diff --git a/include/linux/leds.h b/include/linux/leds.h
index d33b230ce66d..e8e99cc5f99e 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -363,6 +363,7 @@ struct gpio_led {
unsigned gpio;
unsigned active_low : 1;
unsigned retain_state_suspended : 1;
+ unsigned panic_blink : 1;
unsigned default_state : 2;
/* default_state should be one of LEDS_GPIO_DEFSTATE_(ON|OFF|KEEP) */
struct gpio_desc *gpiod;
--
2.7.0