diff options
Diffstat (limited to 'Documentation/leds')
| -rw-r--r-- | Documentation/leds/leds-class-flash.txt | 51 | ||||
| -rw-r--r-- | Documentation/leds/leds-class.txt | 3 | ||||
| -rw-r--r-- | Documentation/leds/leds-lp5523.txt | 30 |
3 files changed, 81 insertions, 3 deletions
diff --git a/Documentation/leds/leds-class-flash.txt b/Documentation/leds/leds-class-flash.txt index 19bb67355..8da3c6f4b 100644 --- a/Documentation/leds/leds-class-flash.txt +++ b/Documentation/leds/leds-class-flash.txt @@ -20,3 +20,54 @@ Following sysfs attributes are exposed for controlling flash LED devices: - max_flash_timeout - flash_strobe - flash_fault + + +V4L2 flash wrapper for flash LEDs +================================= + +A LED subsystem driver can be controlled also from the level of VideoForLinux2 +subsystem. In order to enable this CONFIG_V4L2_FLASH_LED_CLASS symbol has to +be defined in the kernel config. + +The driver must call the v4l2_flash_init function to get registered in the +V4L2 subsystem. The function takes six arguments: +- dev : flash device, e.g. an I2C device +- of_node : of_node of the LED, may be NULL if the same as device's +- fled_cdev : LED flash class device to wrap +- iled_cdev : LED flash class device representing indicator LED associated with + fled_cdev, may be NULL +- ops : V4L2 specific ops + * external_strobe_set - defines the source of the flash LED strobe - + V4L2_CID_FLASH_STROBE control or external source, typically + a sensor, which makes it possible to synchronise the flash + strobe start with exposure start, + * intensity_to_led_brightness and led_brightness_to_intensity - perform + enum led_brightness <-> V4L2 intensity conversion in a device + specific manner - they can be used for devices with non-linear + LED current scale. +- config : configuration for V4L2 Flash sub-device + * dev_name - the name of the media entity, unique in the system, + * flash_faults - bitmask of flash faults that the LED flash class + device can report; corresponding LED_FAULT* bit definitions are + available in <linux/led-class-flash.h>, + * torch_intensity - constraints for the LED in TORCH mode + in microamperes, + * indicator_intensity - constraints for the indicator LED + in microamperes, + * has_external_strobe - determines whether the flash strobe source + can be switched to external, + +On remove the v4l2_flash_release function has to be called, which takes one +argument - struct v4l2_flash pointer returned previously by v4l2_flash_init. +This function can be safely called with NULL or error pointer argument. + +Please refer to drivers/leds/leds-max77693.c for an exemplary usage of the +v4l2 flash wrapper. + +Once the V4L2 sub-device is registered by the driver which created the Media +controller device, the sub-device node acts just as a node of a native V4L2 +flash API device would. The calls are simply routed to the LED flash API. + +Opening the V4L2 flash sub-device makes the LED subsystem sysfs interface +unavailable. The interface is re-enabled after the V4L2 flash sub-device +is closed. diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt index 79699c200..62261c040 100644 --- a/Documentation/leds/leds-class.txt +++ b/Documentation/leds/leds-class.txt @@ -2,9 +2,6 @@ LED handling under Linux ======================== -If you're reading this and thinking about keyboard leds, these are -handled by the input subsystem and the led class is *not* needed. - In its simplest form, the LED class just allows control of LEDs from userspace. LEDs appear in /sys/class/leds/. The maximum brightness of the LED is defined in max_brightness file. The brightness file will set the brightness diff --git a/Documentation/leds/leds-lp5523.txt b/Documentation/leds/leds-lp5523.txt index 5b3e91d4a..0dbbd279c 100644 --- a/Documentation/leds/leds-lp5523.txt +++ b/Documentation/leds/leds-lp5523.txt @@ -49,6 +49,36 @@ There are two ways to run LED patterns. 2) Firmware interface - LP55xx common interface For the details, please refer to 'firmware' section in leds-lp55xx.txt +LP5523 has three master faders. If a channel is mapped to one of +the master faders, its output is dimmed based on the value of the master +fader. + +For example, + + echo "123000123" > master_fader_leds + +creates the following channel-fader mappings: + + channel 0,6 to master_fader1 + channel 1,7 to master_fader2 + channel 2,8 to master_fader3 + +Then, to have 25% of the original output on channel 0,6: + + echo 64 > master_fader1 + +To have 0% of the original output (i.e. no output) channel 1,7: + + echo 0 > master_fader2 + +To have 100% of the original output (i.e. no dimming) on channel 2,8: + + echo 255 > master_fader3 + +To clear all master fader controls: + + echo "000000000" > master_fader_leds + Selftest uses always the current from the platform data. Each channel contains led current settings. |