1Kernel driver lp855x 2==================== 3 4Backlight driver for LP855x ICs 5 6Supported chips: 7 Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8556 and LP8557 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/lp8557 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* device_control : Value of DEVICE CONTROL register. 36* initial_brightness : Initial value of backlight brightness. 37* period_ns : Platform specific PWM period value. unit is nano. 38 Only valid when brightness is pwm input mode. 39* size_program : Total size of lp855x_rom_data. 40* rom_data : List of new eeprom/eprom registers. 41 42example 1) lp8552 platform data : i2c register mode with new eeprom data 43 44#define EEPROM_A5_ADDR 0xA5 45#define EEPROM_A5_VAL 0x4f /* EN_VSYNC=0 */ 46 47static struct lp855x_rom_data lp8552_eeprom_arr[] = { 48 {EEPROM_A5_ADDR, EEPROM_A5_VAL}, 49}; 50 51static struct lp855x_platform_data lp8552_pdata = { 52 .name = "lcd-bl", 53 .device_control = I2C_CONFIG(LP8552), 54 .initial_brightness = INITIAL_BRT, 55 .size_program = ARRAY_SIZE(lp8552_eeprom_arr), 56 .rom_data = lp8552_eeprom_arr, 57}; 58 59example 2) lp8556 platform data : pwm input mode with default rom data 60 61static struct lp855x_platform_data lp8556_pdata = { 62 .device_control = PWM_CONFIG(LP8556), 63 .initial_brightness = INITIAL_BRT, 64 .period_ns = 1000000, 65}; 66