====================
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Kernel driver lp855x
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====================
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Backlight driver for LP855x ICs
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Supported chips:
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Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8555, LP8556 and
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LP8557
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Author: Milo(Woogyom) Kim <milo.kim@ti.com>
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Description
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-----------
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* Brightness control
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Brightness can be controlled by the pwm input or the i2c command.
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The lp855x driver supports both cases.
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* Device attributes
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1) bl_ctl_mode
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Backlight control mode.
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Value: pwm based or register based
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2) chip_id
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The lp855x chip id.
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Value: lp8550/lp8551/lp8552/lp8553/lp8555/lp8556/lp8557
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Platform data for lp855x
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------------------------
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For supporting platform specific data, the lp855x platform data can be used.
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* name:
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Backlight driver name. If it is not defined, default name is set.
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* device_control:
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Value of DEVICE CONTROL register.
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* initial_brightness:
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Initial value of backlight brightness.
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* period_ns:
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Platform specific PWM period value. unit is nano.
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Only valid when brightness is pwm input mode.
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* size_program:
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Total size of lp855x_rom_data.
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* rom_data:
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List of new eeprom/eprom registers.
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Examples
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========
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1) lp8552 platform data: i2c register mode with new eeprom data::
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#define EEPROM_A5_ADDR 0xA5
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#define EEPROM_A5_VAL 0x4f /* EN_VSYNC=0 */
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static struct lp855x_rom_data lp8552_eeprom_arr[] = {
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{EEPROM_A5_ADDR, EEPROM_A5_VAL},
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};
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static struct lp855x_platform_data lp8552_pdata = {
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.name = "lcd-bl",
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.device_control = I2C_CONFIG(LP8552),
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.initial_brightness = INITIAL_BRT,
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.size_program = ARRAY_SIZE(lp8552_eeprom_arr),
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.rom_data = lp8552_eeprom_arr,
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};
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2) lp8556 platform data: pwm input mode with default rom data::
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static struct lp855x_platform_data lp8556_pdata = {
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.device_control = PWM_CONFIG(LP8556),
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.initial_brightness = INITIAL_BRT,
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.period_ns = 1000000,
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};
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