1 ====================
2 Kernel driver lp855x
3 ====================
4
5 Backlight driver for LP855x ICs
6
7 Supported chips:
8
9 Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8555, LP8556 and
10 LP8557
11
12 Author: Milo(Woogyom) Kim <milo.kim@ti.com>
13
14 Description
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
36 Platform data for lp855x
37 ------------------------
38
39 For 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
55 Examples
56 ========
57
58 1) 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
75 2) 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 };
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