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Documentation / leds / leds-lp5562.txt




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Based on kernel version 3.13. Page generated on 2014-01-20 22:03 EST.

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