Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx> Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> Cc: Bryan Wu <cooloney@xxxxxxxxx> Cc: Richard Purdie <rpurdie@xxxxxxxxx> --- Documentation/leds/leds-class.txt | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt index 62261c0..d34d990 100644 --- a/Documentation/leds/leds-class.txt +++ b/Documentation/leds/leds-class.txt @@ -8,6 +8,31 @@ LED is defined in max_brightness file. The brightness file will set the brightne of the LED (taking a value 0-max_brightness). Most LEDs don't have hardware brightness support so will just be turned on for non-zero brightness settings. +Some LED devices support two modes - torch and flash. A LED subsystem device +driver can declare this by calling led_classdev_init_flash function and +initializing flash field of the led_classdev structure (see <linux/leds.h>). +There are five sysfs attributes dedicated specifically to the flash LED devices: + + - flash_mode - sets/unsets the flash mode + - flash_timeout - determines duration of the flash blink in milliseconds + - max_flash_timeout - maximum flash blink duration that can be set (RO) + - flash_fault - bitmask of flash faults that may have occured, possible + flags are: + * 0x01 - Flash controller voltage to the flash LED has exceeded + the limit specific to the flash controller. + * 0x02 - The flash strobe was still on when the timeout set by + the user has expired. Not all flash controllers may set + this in all such conditions. + * 0x04 - The flash controller has overheated. + * 0x08 - The short circuit protection of the flash controller + has been triggered. + * 0x10 - Current in the LED power supply has exceeded the limit + specific to the flash controller. + - hw_triggered - Some devices expose dedicated hardware pins for + triggering a flash LED. The attribute allows to set + this mode. After writting 1 the brightness has to be set + to the desired value to arm a led. + The class also introduces the optional concept of an LED trigger. A trigger is a kernel based source of led events. Triggers can either be simple or complex. A simple trigger isn't configurable and is designed to slot into -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
