This small file seems to be an attempt to start documenting
backlight drivers.
It contains descriptions of the controls for the driver
with could sound as an somewhat user-faced description, but
it's main focus is to describe, instead, the data that should
be passed via platform data and some driver-specific stuff.
Signed-off-by: Mauro Carvalho Chehab <mchehab+sams...@kernel.org>
---
Documentation/backlight/lp855x-driver.txt | 65 ++++++++++++++---------
1 file changed, 40 insertions(+), 25 deletions(-)
diff --git a/Documentation/backlight/lp855x-driver.txt
b/Documentation/backlight/lp855x-driver.txt
index 01bce243d3d7..1e0b224fc397 100644
--- a/Documentation/backlight/lp855x-driver.txt
+++ b/Documentation/backlight/lp855x-driver.txt
@@ -1,9 +1,11 @@
+====================
Kernel driver lp855x
====================
Backlight driver for LP855x ICs
Supported chips:
+
Texas Instruments LP8550, LP8551, LP8552, LP8553, LP8555, LP8556 and
LP8557
@@ -14,53 +16,66 @@ Description
* Brightness control
-Brightness can be controlled by the pwm input or the i2c command.
-The lp855x driver supports both cases.
+ 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
+ 1) bl_ctl_mode
-2) chip_id
-The lp855x chip id.
-Value : lp8550/lp8551/lp8552/lp8553/lp8555/lp8556/lp8557
+ 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.
+* 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
+Examples
+========
-#define EEPROM_A5_ADDR 0xA5
-#define EEPROM_A5_VAL 0x4f /* EN_VSYNC=0 */
+1) lp8552 platform data: i2c register mode with new eeprom data::
-static struct lp855x_rom_data lp8552_eeprom_arr[] = {
+ #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 = {
+ 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
+2) lp8556 platform data: pwm input mode with default rom data::
-static struct lp855x_platform_data lp8556_pdata = {
+ static struct lp855x_platform_data lp8556_pdata = {
.device_control = PWM_CONFIG(LP8556),
.initial_brightness = INITIAL_BRT,
.period_ns = 1000000,
-};
+ };
--
2.20.1
