Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney...

[karo-tx-linux.git] / Documentation / leds / leds-lp5562.txt

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+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.