1====================
2Kernel driver lp855x
3====================
4
5Backlight driver for LP855x ICs
6
7Supported chips:
8
9	Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8555, LP8556 and
10	LP8557
11
12Author: Milo(Woogyom) Kim <milo.kim@ti.com>
13
14Description
15-----------
16
17* Brightness control
18
19  Brightness can be controlled by the pwm input or the i2c command.
20  The lp855x driver supports both cases.
21
22* Device attributes
23
24  1) bl_ctl_mode
25
26  Backlight control mode.
27
28  Value: pwm based or register based
29
30  2) chip_id
31
32  The lp855x chip id.
33
34  Value: lp8550/lp8551/lp8552/lp8553/lp8555/lp8556/lp8557
35
36Platform data for lp855x
37------------------------
38
39For supporting platform specific data, the lp855x platform data can be used.
40
41* name:
42	Backlight driver name. If it is not defined, default name is set.
43* device_control:
44	Value of DEVICE CONTROL register.
45* initial_brightness:
46	Initial value of backlight brightness.
47* period_ns:
48	Platform specific PWM period value. unit is nano.
49	Only valid when brightness is pwm input mode.
50* size_program:
51	Total size of lp855x_rom_data.
52* rom_data:
53	List of new eeprom/eprom registers.
54
55Examples
56========
57
581) lp8552 platform data: i2c register mode with new eeprom data::
59
60    #define EEPROM_A5_ADDR	0xA5
61    #define EEPROM_A5_VAL	0x4f	/* EN_VSYNC=0 */
62
63    static struct lp855x_rom_data lp8552_eeprom_arr[] = {
64	{EEPROM_A5_ADDR, EEPROM_A5_VAL},
65    };
66
67    static struct lp855x_platform_data lp8552_pdata = {
68	.name = "lcd-bl",
69	.device_control = I2C_CONFIG(LP8552),
70	.initial_brightness = INITIAL_BRT,
71	.size_program = ARRAY_SIZE(lp8552_eeprom_arr),
72	.rom_data = lp8552_eeprom_arr,
73    };
74
752) lp8556 platform data: pwm input mode with default rom data::
76
77    static struct lp855x_platform_data lp8556_pdata = {
78	.device_control = PWM_CONFIG(LP8556),
79	.initial_brightness = INITIAL_BRT,
80	.period_ns = 1000000,
81    };
82