From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- Documentation/backlight/lp855x-driver.txt | 66 +++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 Documentation/backlight/lp855x-driver.txt (limited to 'Documentation/backlight') diff --git a/Documentation/backlight/lp855x-driver.txt b/Documentation/backlight/lp855x-driver.txt new file mode 100644 index 000000000..01bce243d --- /dev/null +++ b/Documentation/backlight/lp855x-driver.txt @@ -0,0 +1,66 @@ +Kernel driver lp855x +==================== + +Backlight driver for LP855x ICs + +Supported chips: + Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8555, LP8556 and + LP8557 + +Author: Milo(Woogyom) Kim + +Description +----------- + +* Brightness control + +Brightness can be controlled by the pwm input or the i2c command. +The lp855x driver supports both cases. + +* Device attributes + +1) bl_ctl_mode +Backlight control mode. +Value : pwm based or register based + +2) chip_id +The lp855x chip id. +Value : lp8550/lp8551/lp8552/lp8553/lp8555/lp8556/lp8557 + +Platform data for lp855x +------------------------ + +For supporting platform specific data, the lp855x platform data can be used. + +* name : Backlight driver name. If it is not defined, default name is set. +* device_control : Value of DEVICE CONTROL register. +* initial_brightness : Initial value of backlight brightness. +* period_ns : Platform specific PWM period value. unit is nano. + Only valid when brightness is pwm input mode. +* size_program : Total size of lp855x_rom_data. +* rom_data : List of new eeprom/eprom registers. + +example 1) lp8552 platform data : i2c register mode with new eeprom data + +#define EEPROM_A5_ADDR 0xA5 +#define EEPROM_A5_VAL 0x4f /* EN_VSYNC=0 */ + +static struct lp855x_rom_data lp8552_eeprom_arr[] = { + {EEPROM_A5_ADDR, EEPROM_A5_VAL}, +}; + +static struct lp855x_platform_data lp8552_pdata = { + .name = "lcd-bl", + .device_control = I2C_CONFIG(LP8552), + .initial_brightness = INITIAL_BRT, + .size_program = ARRAY_SIZE(lp8552_eeprom_arr), + .rom_data = lp8552_eeprom_arr, +}; + +example 2) lp8556 platform data : pwm input mode with default rom data + +static struct lp855x_platform_data lp8556_pdata = { + .device_control = PWM_CONFIG(LP8556), + .initial_brightness = INITIAL_BRT, + .period_ns = 1000000, +}; -- cgit v1.2.3