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Diffstat (limited to 'Documentation/leds/leds-lp5562.txt')
-rw-r--r-- | Documentation/leds/leds-lp5562.txt | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/Documentation/leds/leds-lp5562.txt b/Documentation/leds/leds-lp5562.txt new file mode 100644 index 000000000000..96061000dd93 --- /dev/null +++ b/Documentation/leds/leds-lp5562.txt @@ -0,0 +1,135 @@ +Kernel driver for LP5562 +======================== + +* TI LP5562 LED Driver + +Author: Milo(Woogyom) Kim <milo.kim@ti.com> + +Description + + LP5562 can drive up to 4 channels. R/G/B and White. + LEDs can be controlled directly via the led class control interface. + + All four channels can be also controlled using the engine micro programs. + LP5562 has the internal program memory for running various LED patterns. + For the details, please refer to 'firmware' section in leds-lp55xx.txt + +Device attribute: engine_mux + + 3 Engines are allocated in LP5562, but the number of channel is 4. + Therefore each channel should be mapped to the engine number. + Value : RGB or W + + This attribute is used for programming LED data with the firmware interface. + Unlike the LP5521/LP5523/55231, LP5562 has unique feature for the engine mux, + so additional sysfs is required. + + LED Map + Red ... Engine 1 (fixed) + Green ... Engine 2 (fixed) + Blue ... Engine 3 (fixed) + White ... Engine 1 or 2 or 3 (selective) + +How to load the program data using engine_mux + + Before loading the LP5562 program data, engine_mux should be written between + the engine selection and loading the firmware. + Engine mux has two different mode, RGB and W. + RGB is used for loading RGB program data, W is used for W program data. + + For example, run blinking green channel pattern, + echo 2 > /sys/bus/i2c/devices/xxxx/select_engine # 2 is for green channel + echo "RGB" > /sys/bus/i2c/devices/xxxx/engine_mux # engine mux for RGB + echo 1 > /sys/class/firmware/lp5562/loading + echo "4000600040FF6000" > /sys/class/firmware/lp5562/data + echo 0 > /sys/class/firmware/lp5562/loading + echo 1 > /sys/bus/i2c/devices/xxxx/run_engine + + To run a blinking white pattern, + echo 1 or 2 or 3 > /sys/bus/i2c/devices/xxxx/select_engine + echo "W" > /sys/bus/i2c/devices/xxxx/engine_mux + echo 1 > /sys/class/firmware/lp5562/loading + echo "4000600040FF6000" > /sys/class/firmware/lp5562/data + echo 0 > /sys/class/firmware/lp5562/loading + echo 1 > /sys/bus/i2c/devices/xxxx/run_engine + +How to load the predefined patterns + + Please refer to 'leds-lp55xx.txt" + +Setting Current of Each Channel + + Like LP5521 and LP5523/55231, LP5562 provides LED current settings. + The 'led_current' and 'max_current' are used. + +(Example of Platform data) + +To configure the platform specific data, lp55xx_platform_data structure is used. + +static struct lp55xx_led_config lp5562_led_config[] = { + { + .name = "R", + .chan_nr = 0, + .led_current = 20, + .max_current = 40, + }, + { + .name = "G", + .chan_nr = 1, + .led_current = 20, + .max_current = 40, + }, + { + .name = "B", + .chan_nr = 2, + .led_current = 20, + .max_current = 40, + }, + { + .name = "W", + .chan_nr = 3, + .led_current = 20, + .max_current = 40, + }, +}; + +static int lp5562_setup(void) +{ + /* setup HW resources */ +} + +static void lp5562_release(void) +{ + /* Release HW resources */ +} + +static void lp5562_enable(bool state) +{ + /* Control of chip enable signal */ +} + +static struct lp55xx_platform_data lp5562_platform_data = { + .led_config = lp5562_led_config, + .num_channels = ARRAY_SIZE(lp5562_led_config), + .setup_resources = lp5562_setup, + .release_resources = lp5562_release, + .enable = lp5562_enable, +}; + +If the current is set to 0 in the platform data, that channel is +disabled and it is not visible in the sysfs. + +The 'update_config' : CONFIG register (ADDR 08h) +This value is platform-specific data. +If update_config is not defined, the CONFIG register is set with +'LP5562_PWRSAVE_EN | LP5562_CLK_AUTO'. +(Enable auto-powersave, set automatic clock source selection) + +#define LP5562_CONFIGS (LP5562_PWM_HF | LP5562_PWRSAVE_EN | \ + LP5562_CLK_SRC_EXT) + +static struct lp55xx_platform_data lp5562_pdata = { + .led_config = lp5562_led_config, + .num_channels = ARRAY_SIZE(lp5562_led_config), + .update_config = LP5562_CONFIGS, +}; |