| Message ID | 1415808557-29557-4-git-send-email-j.anaszewski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Nov 12, 2014 at 8:09 AM, Jacek Anaszewski <j.anaszewski@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.anaszewski@samsung.com> > Acked-by: Kyungmin Park <kyungmin.park@samsung.com> > Cc: Bryan Wu <cooloney@gmail.com> > Cc: Richard Purdie <rpurdie@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 0000000..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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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.anaszewski@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.anaszewski@samsung.com> >> Acked-by: Kyungmin Park <kyungmin.park@samsung.com> >> Cc: Bryan Wu <cooloney@gmail.com> >> Cc: Richard Purdie <rpurdie@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 0000000..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 controller? Or just for > some specific chip? They are generic error codes, and map directly to V4L2 Flash errors. Error descriptions were copied from the V4L2 Flash documentation. Best Regards, Jacek Anaszewski -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/leds/leds-class-flash.txt b/Documentation/leds/leds-class-flash.txt new file mode 100644 index 0000000..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