From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout1.samsung.com ([203.254.224.24]:26257 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751560AbaLCQHV (ORCPT ); Wed, 3 Dec 2014 11:07:21 -0500 From: Jacek Anaszewski To: linux-leds@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: kyungmin.park@samsung.com, b.zolnierkie@samsung.com, pavel@ucw.cz, cooloney@gmail.com, rpurdie@rpsys.net, sakari.ailus@iki.fi, s.nawrocki@samsung.com, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, Jacek Anaszewski Subject: [PATCH/RFC v9 02/19] Documentation: leds: Add description of LED Flash class extension Date: Wed, 03 Dec 2014 17:06:37 +0100 Message-id: <1417622814-10845-3-git-send-email-j.anaszewski@samsung.com> In-reply-to: <1417622814-10845-1-git-send-email-j.anaszewski@samsung.com> References: <1417622814-10845-1-git-send-email-j.anaszewski@samsung.com> Sender: linux-media-owner@vger.kernel.org List-ID: The documentation being added contains overall description of the LED Flash Class and the related sysfs attributes. Signed-off-by: Jacek Anaszewski Acked-by: Kyungmin Park Cc: Bryan Wu Cc: Richard Purdie --- Documentation/leds/leds-class-flash.txt | 50 +++++++++++++++++++++++++++++++ 1 file changed, 50 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..82e58b1 --- /dev/null +++ b/Documentation/leds/leds-class-flash.txt @@ -0,0 +1,50 @@ + +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) + - 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 one controlled by the same + device; flash timeout setting is inherited + from the led being strobed explicitly and + flash brightness setting of a sub-led's + being synchronized is used (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 + + Flash faults are cleared by reading the attribute. -- 1.7.9.5