Re: [PATCH/RFC v10 02/19] Documentation: leds: Add description of LED Flash class extension

From: Pavel Machek
Date: Fri Jan 09 2015 - 12:41:07 EST


Hi!

> 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>

> +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

sub-LED?

> + - 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
> + * 0x20 - the flash controller has detected a short or open
> + circuit condition on the indicator LED
> + * 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

Did not everyone agree that text strings are preferable to bitmasks?

Pavel

--
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