Re: [PATCH/RFC v7 3/3] Documentation: leds: Add description of LED Flash Class extension
Hi Bryan, Thanks for a review. On 11/13/2014 07:58 PM, Bryan Wu wrote: On Wed, Nov 12, 2014 at 8:09 AM, Jacek Anaszewski j.anaszew...@samsung.com wrote: The documentation being added contains overall description of the LED Flash Class and the related sysfs attributes. Signed-off-by: Jacek Anaszewski j.anaszew...@samsung.com Acked-by: Kyungmin Park kyungmin.p...@samsung.com Cc: Bryan Wu coolo...@gmail.com Cc: Richard Purdie rpur...@rpsys.net --- Documentation/leds/leds-class-flash.txt | 39 +++ 1 file changed, 39 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 000..0164329 --- /dev/null +++ b/Documentation/leds/leds-class-flash.txt @@ -0,0 +1,39 @@ + +Flash LED handling under Linux +== + +Some LED devices support two modes - torch and flash. In order to enable I think I asked this question before, Torch, Flash and Indicator. As you answered torch is implemented by sync led brightness set operation in our LEDS_CLASS and Flash is implemented in this LEDS_CLASS_FLASH. I suggest put this information in document or code comments. Then people know how to use torch and flash. Good point. For indicator I still don't know why we need this since indicator is like blinking and it should be support by LEDS_CLASS right? Indicator led is strictly related to flash devices. It is also called a privacy led because of its purpose - protecting a privacy of a person being recorded by providing a light signal signifying that a camera is on. It is a low current led, but some devices use the same led as for torch and flash and only apply reduced current in the indicator mode. In the V4L2 subsystem I see only one driver supporting indicator leds: /drivers/media/i2c/as3645a.c. It looks like indicator intensity can be set only when flash mode is V4L2_FLASH_LED_MODE_NONE, i.e. torch and flash leds cannot be active simultaneously with indicator led. It is reasonable, as active torch led is a sufficient signalization of recording. In the LED subsystem I also see indicators in some drivers, e.g. leds-lm355x.c, but they are registered as a separate LED class devices. Moreover the driver adds also a pattern sysfs attribute for choosing indicator blinking pattern so that is something to be added to the LED Flash class. I think that similar improvement to the V4L2 Flash API should be made. Sakari, what is your opinion? Flash is for some camera capture, right? +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) What's the privacy mean here? Indeed, consistent naming should be applied, so I will modify it to: maximum indicator LED brightness in microaperes (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_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 Are these error code the same for all the LED
Re: [PATCH/RFC v7 3/3] Documentation: leds: Add description of LED Flash Class extension
On Wed, Nov 12, 2014 at 8:09 AM, Jacek Anaszewski j.anaszew...@samsung.com wrote: The documentation being added contains overall description of the LED Flash Class and the related sysfs attributes. Signed-off-by: Jacek Anaszewski j.anaszew...@samsung.com Acked-by: Kyungmin Park kyungmin.p...@samsung.com Cc: Bryan Wu coolo...@gmail.com Cc: Richard Purdie rpur...@rpsys.net --- Documentation/leds/leds-class-flash.txt | 39 +++ 1 file changed, 39 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 000..0164329 --- /dev/null +++ b/Documentation/leds/leds-class-flash.txt @@ -0,0 +1,39 @@ + +Flash LED handling under Linux +== + +Some LED devices support two modes - torch and flash. In order to enable I think I asked this question before, Torch, Flash and Indicator. As you answered torch is implemented by sync led brightness set operation in our LEDS_CLASS and Flash is implemented in this LEDS_CLASS_FLASH. I suggest put this information in document or code comments. Then people know how to use torch and flash. For indicator I still don't know why we need this since indicator is like blinking and it should be support by LEDS_CLASS right? Flash is for some camera capture, right? +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) What's the privacy mean here? + - flash_timeout - flash strobe duration in microseconds (RW) + - max_flash_timeout - maximum available flash strobe duration (RO) + - flash_strobe - flash strobe state (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 Are these error code the same for all the LED controller? Or just for some specific chip? -- 1.7.9.5 -- To unsubscribe from this list: send the line unsubscribe linux-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH/RFC v7 3/3] Documentation: leds: Add description of LED Flash Class extension
The documentation being added contains overall description of the LED Flash Class and the related sysfs attributes. Signed-off-by: Jacek Anaszewski j.anaszew...@samsung.com Acked-by: Kyungmin Park kyungmin.p...@samsung.com Cc: Bryan Wu coolo...@gmail.com Cc: Richard Purdie rpur...@rpsys.net --- Documentation/leds/leds-class-flash.txt | 39 +++ 1 file changed, 39 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 000..0164329 --- /dev/null +++ b/Documentation/leds/leds-class-flash.txt @@ -0,0 +1,39 @@ + +Flash LED handling under Linux +== + +Some LED devices support two modes - torch and flash. 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_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-media in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
