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author | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-06-18 11:44:24 -0300 |
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committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-07-15 11:03:02 -0300 |
commit | 56198359b64125dd0f9fa991972b61e4bc4fc6b5 (patch) | |
tree | 1a2989ededcafd625957e1adde848ec3804ff593 /Documentation/driver-api/backlight | |
parent | 2dbc0838bcf24ca59cabc3130cf3b1d6809cdcd4 (diff) | |
download | linux-56198359b64125dd0f9fa991972b61e4bc4fc6b5.tar.gz linux-56198359b64125dd0f9fa991972b61e4bc4fc6b5.tar.bz2 linux-56198359b64125dd0f9fa991972b61e4bc4fc6b5.zip |
docs: lp855x-driver.rst: add it to the driver-api book
The content of this file is intended for backlight Kernel
developers.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Diffstat (limited to 'Documentation/driver-api/backlight')
-rw-r--r-- | Documentation/driver-api/backlight/lp855x-driver.rst | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/Documentation/driver-api/backlight/lp855x-driver.rst b/Documentation/driver-api/backlight/lp855x-driver.rst new file mode 100644 index 000000000000..1e0b224fc397 --- /dev/null +++ b/Documentation/driver-api/backlight/lp855x-driver.rst @@ -0,0 +1,81 @@ +==================== +Kernel driver lp855x +==================== + +Backlight driver for LP855x ICs + +Supported chips: + + Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8555, LP8556 and + LP8557 + +Author: Milo(Woogyom) Kim <milo.kim@ti.com> + +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. + +Examples +======== + +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, + }; + +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, + }; |