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1Kernel driver lp855x
2====================
3
4Backlight driver for LP855x ICs
5
6Supported chips:
7 Texas Instruments LP8550, LP8551, LP8552, LP8553 and LP8556
8
9Author: Milo(Woogyom) Kim <milo.kim@ti.com>
10
11Description
12-----------
13
14* Brightness control
15
16Brightness can be controlled by the pwm input or the i2c command.
17The lp855x driver supports both cases.
18
19* Device attributes
20
211) bl_ctl_mode
22Backlight control mode.
23Value : pwm based or register based
24
252) chip_id
26The lp855x chip id.
27Value : lp8550/lp8551/lp8552/lp8553/lp8556
28
29Platform data for lp855x
30------------------------
31
32For supporting platform specific data, the lp855x platform data can be used.
33
34* name : Backlight driver name. If it is not defined, default name is set.
35* mode : Brightness control mode. PWM or register based.
36* device_control : Value of DEVICE CONTROL register.
37* initial_brightness : Initial value of backlight brightness.
38* pwm_data : Platform specific pwm generation functions.
39 Only valid when brightness is pwm input mode.
40 Functions should be implemented by PWM driver.
41 - pwm_set_intensity() : set duty of PWM
42 - pwm_get_intensity() : get current duty of PWM
43* load_new_rom_data :
44 0 : use default configuration data
45 1 : update values of eeprom or eprom registers on loading driver
46* size_program : Total size of lp855x_rom_data.
47* rom_data : List of new eeprom/eprom registers.
48
49example 1) lp8552 platform data : i2c register mode with new eeprom data
50
51#define EEPROM_A5_ADDR 0xA5
52#define EEPROM_A5_VAL 0x4f /* EN_VSYNC=0 */
53
54static struct lp855x_rom_data lp8552_eeprom_arr[] = {
55 {EEPROM_A5_ADDR, EEPROM_A5_VAL},
56};
57
58static struct lp855x_platform_data lp8552_pdata = {
59 .name = "lcd-bl",
60 .mode = REGISTER_BASED,
61 .device_control = I2C_CONFIG(LP8552),
62 .initial_brightness = INITIAL_BRT,
63 .load_new_rom_data = 1,
64 .size_program = ARRAY_SIZE(lp8552_eeprom_arr),
65 .rom_data = lp8552_eeprom_arr,
66};
67
68example 2) lp8556 platform data : pwm input mode with default rom data
69
70static struct lp855x_platform_data lp8556_pdata = {
71 .mode = PWM_BASED,
72 .device_control = PWM_CONFIG(LP8556),
73 .initial_brightness = INITIAL_BRT,
74 .pwm_data = {
75 .pwm_set_intensity = platform_pwm_set_intensity,
76 .pwm_get_intensity = platform_pwm_get_intensity,
77 },
78};