The documentation being added contains overall description of the LED Flash Class and the related sysfs attributes.
Signed-off-by: Jacek Anaszewski <[email protected]> Acked-by: Kyungmin Park <[email protected]> Cc: Bryan Wu <[email protected]> Cc: Richard Purdie <[email protected]> --- Documentation/leds/leds-class-flash.txt | 48 +++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 Documentation/leds/leds-class-flash.txt diff --git a/Documentation/leds/leds-class-flash.txt b/Documentation/leds/leds-class-flash.txt new file mode 100644 index 0000000..d68565c --- /dev/null +++ b/Documentation/leds/leds-class-flash.txt @@ -0,0 +1,48 @@ + +Flash LED handling under Linux +============================== + +Some LED devices support two modes - torch and flash. The modes are +supported by the LED class (see Documentation/leds/leds-class.txt) +and LED Flash class respectively. + +In order to enable support for flash LEDs CONFIG_LEDS_CLASS_FLASH symbol +must be defined in the kernel config. A flash LED driver must register +in the LED subsystem with led_classdev_flash_register to gain flash +capabilities. + +Following sysfs attributes are exposed for controlling flash led devices: + + - flash_brightness - flash LED brightness in microamperes (RW) + - max_flash_brightness - maximum available flash LED brightness (RO) + - indicator_brightness - privacy LED brightness in microamperes (RW) + - max_indicator_brightness - maximum privacy LED brightness in + microamperes (RO) + - flash_timeout - flash strobe duration in microseconds (RW) + - max_flash_timeout - maximum available flash strobe duration (RO) + - flash_strobe - flash strobe state (RW) + - flash_sync_strobe - one flash device can control more than one + sub-led; when this atrribute is set to 1 + the flash led will be strobed synchronously + with the other ones controlled by the same + device (RW) + - flash_fault - bitmask of flash faults that may have occurred, + 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 + * 0x40 - flash controller voltage to the flash LED has been + below the minimum limit specific to the flash + * 0x80 - the input voltage of the flash controller is below + the limit under which strobing the flash at full + current will not be possible. The condition persists + until this flag is no longer set + * 0x100 - the temperature of the LED has exceeded its allowed + upper limit -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
