On Thu, Feb 5, 2015 at 12:42 AM, Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx> wrote: > The documentation being added contains overall description of the > LED Flash Class and the related sysfs attributes. > > 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> > --- Jacek, I lost the discussion here. Did you change something since V1 patch? Pavel, Is this version OK for you? -Bryan > Documentation/leds/leds-class-flash.txt | 63 +++++++++++++++++++++++++++++++ > 1 file changed, 63 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..16c6187 > --- /dev/null > +++ b/Documentation/leds/leds-class-flash.txt > @@ -0,0 +1,63 @@ > + > +Flash LED handling under Linux > +============================== > + > +Some LED devices support two modes - torch and flash. In the LED subsystem > +those modes are supported by LED class (see Documentation/leds/leds-class.txt) > +and LED Flash class respectively. The torch mode related features are enabled > +by default and the flash ones only if a driver declares it by setting > +LED_DEV_CAP_FLASH flag. > + > +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 function to gain flash > +related capabilities. > + > +There are flash LED devices which can control more than one LED and allow for > +strobing the sub-LEDs synchronously. A LED will be strobed synchronously with > +the one whose identifier is written to the flash_sync_strobe sysfs attribute. > +The list of available sub-LED identifiers can be read from the available_sync_leds > +sysfs attribute. In order to enable the related settings the driver must set > +LED_DEV_CAP_SYNC_STROBE flag. > + > +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) > + - flash_timeout - flash strobe duration in microseconds (RW) > + - max_flash_timeout - maximum available flash strobe duration (RO) > + - flash_strobe - flash strobe state (RW) > + - available_sync_leds - list of sub-LEDs available for flash strobe > + synchronization (RO) > + - flash_sync_strobe - identifier of the sub-LED to synchronize the flash > + strobe with; 0 stands for no synchronization (RW) > + - flash_fault - list of flash faults that may have occurred: > + * led-over-voltage - flash controller voltage to the flash LED > + has exceededthe limit specific to the flash controller > + * flash-timeout-exceeded - 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 > + * controller-over-temperature - the flash controller has > + overheated > + * controller-short-circuit - the short circuit protection > + of the flash controller has been triggered > + * led-power-supply-over-current - current in the LED power > + supply has exceeded the limit specific to the flash > + controller > + * indicator-led-fault - the flash controller has detected > + a short or open circuit condition on the indicator LED > + * led-under-voltage - flash controller voltage to the flash > + LED has been below the minimum limit specific to > + the flash > + * controller-under-voltage - 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 > + * led-over-temperature - the temperature of the LED has exceeded > + its allowed upper limit > + > + Flash faults should be read in the strobe_set callback, right > + after the instruction initiating the strobe. If a flash LED > + device provides an instruction for clearing the faults, then, > + in case there were any faults read, it should be also executed > + in the callback. > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
