leds-lp5562.rst

  1========================
  2Kernel driver for lp5562
  3========================
  4
  5* TI LP5562 LED Driver
  6
  7Author: Milo(Woogyom) Kim <milo.kim@ti.com>
  8
  9Description
 10===========
 11
 12  LP5562 can drive up to 4 channels. R/G/B and White.
 13  LEDs can be controlled directly via the led class control interface.
 14
 15  All four channels can be also controlled using the engine micro programs.
 16  LP5562 has the internal program memory for running various LED patterns.
 17  For the details, please refer to 'firmware' section in leds-lp55xx.txt
 18
 19Device attribute
 20================
 21
 22engine_mux
 23  3 Engines are allocated in LP5562, but the number of channel is 4.
 24  Therefore each channel should be mapped to the engine number.
 25
 26  Value: RGB or W
 27
 28  This attribute is used for programming LED data with the firmware interface.
 29  Unlike the LP5521/LP5523/55231, LP5562 has unique feature for the engine mux,
 30  so additional sysfs is required
 31
 32  LED Map
 33
 34  ===== === ===============================
 35  Red   ... Engine 1 (fixed)
 36  Green ... Engine 2 (fixed)
 37  Blue  ... Engine 3 (fixed)
 38  White ... Engine 1 or 2 or 3 (selective)
 39  ===== === ===============================
 40
 41How to load the program data using engine_mux
 42=============================================
 43
 44  Before loading the LP5562 program data, engine_mux should be written between
 45  the engine selection and loading the firmware.
 46  Engine mux has two different mode, RGB and W.
 47  RGB is used for loading RGB program data, W is used for W program data.
 48
 49  For example, run blinking green channel pattern::
 50
 51    echo 2 > /sys/bus/i2c/devices/xxxx/select_engine     # 2 is for green channel
 52    echo "RGB" > /sys/bus/i2c/devices/xxxx/engine_mux    # engine mux for RGB
 53    echo 1 > /sys/class/firmware/lp5562/loading
 54    echo "4000600040FF6000" > /sys/class/firmware/lp5562/data
 55    echo 0 > /sys/class/firmware/lp5562/loading
 56    echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
 57
 58  To run a blinking white pattern::
 59
 60    echo 1 or 2 or 3 > /sys/bus/i2c/devices/xxxx/select_engine
 61    echo "W" > /sys/bus/i2c/devices/xxxx/engine_mux
 62    echo 1 > /sys/class/firmware/lp5562/loading
 63    echo "4000600040FF6000" > /sys/class/firmware/lp5562/data
 64    echo 0 > /sys/class/firmware/lp5562/loading
 65    echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
 66
 67How to load the predefined patterns
 68===================================
 69
 70  Please refer to 'leds-lp55xx.txt"
 71
 72Setting Current of Each Channel
 73===============================
 74
 75  Like LP5521 and LP5523/55231, LP5562 provides LED current settings.
 76  The 'led_current' and 'max_current' are used.
 77
 78Example of Platform data
 79========================
 80
 81::
 82
 83	static struct lp55xx_led_config lp5562_led_config[] = {
 84		{
 85			.name 		= "R",
 86			.chan_nr	= 0,
 87			.led_current	= 20,
 88			.max_current	= 40,
 89		},
 90		{
 91			.name 		= "G",
 92			.chan_nr	= 1,
 93			.led_current	= 20,
 94			.max_current	= 40,
 95		},
 96		{
 97			.name 		= "B",
 98			.chan_nr	= 2,
 99			.led_current	= 20,
100			.max_current	= 40,
101		},
102		{
103			.name 		= "W",
104			.chan_nr	= 3,
105			.led_current	= 20,
106			.max_current	= 40,
107		},
108	};
109
110	static int lp5562_setup(void)
111	{
112		/* setup HW resources */
113	}
114
115	static void lp5562_release(void)
116	{
117		/* Release HW resources */
118	}
119
120	static void lp5562_enable(bool state)
121	{
122		/* Control of chip enable signal */
123	}
124
125	static struct lp55xx_platform_data lp5562_platform_data = {
126		.led_config     = lp5562_led_config,
127		.num_channels   = ARRAY_SIZE(lp5562_led_config),
128		.setup_resources   = lp5562_setup,
129		.release_resources = lp5562_release,
130		.enable            = lp5562_enable,
131	};
132
133To configure the platform specific data, lp55xx_platform_data structure is used
134
135
136If the current is set to 0 in the platform data, that channel is
137disabled and it is not visible in the sysfs.