linux-stable.git/Documentation/backlight, branch master

docs: lp855x-driver.rst: add it to the driver-api book

2019-07-15T14:03:02+00:00

The content of this file is intended for backlight Kernel
developers.

Signed-off-by: Mauro Carvalho Chehab

docs: lp855x-driver.txt: convert to ReST and move to kernel-api

2019-07-15T12:20:23+00:00

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.

While this is not part of the driver-api book, mark it as
:orphan:, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab

backlight: lp855x_bl: support new LP8555 device

2013-11-13T03:09:14+00:00

LP8555 is one of the LP855x family devices.

This device needs pre_init_device() and post_init_device() driver
structure.  It's same as LP8557, so the device configuration code is
shared with LP8557.  Backlight outputs are generated from dual DC-DC boost
converters.  It's configurable EPROM settings which are defined in the
platform data.

Driver documentation and device tree bindings are updated.

Signed-off-by: Milo Kim 
Signed-off-by: Jingoo Han 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

backlight: lp855x: remove duplicate platform data

2013-04-30T01:28:19+00:00

The 'load_new_rom_data' was used for checking whether new ROM data should
be updated or not.

However, we can decide it with 'size_program' data.  If the size is
greater than 0, it means updating ROM area is required.  Otherwise, the
default ROM data will be used.  Therefore, this duplicate platform data
can be removed.

Signed-off-by: Milo(Woogyom) Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

backlight: lp855x: move backlight mode platform data

2013-04-30T01:28:18+00:00

The brightness of LP855x devices is controlled by I2C register or PWM
input .  This mode was selected through the platform data, but it can be
chosen by the driver internally without platform data configuration.

How to decide the control mode:
  If the PWM period has specific value, the mode is PWM input.
  On the other hand, the mode is register-based.
  This mode selection is done on the _probe().

Move 'mode' from a header file to the driver private data structure,
'lp855 x'.  And correlated code was replaced.

Signed-off-by: Milo(Woogyom) Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

backlight: lp855x_bl: support new LP8557 device

2013-02-22T01:22:25+00:00

LP8557 is one of LP855x family device, but it has different register map
and initialization process.  To support this device, device specific
configuration is done through the lp855x_device_config structure.

Few register definitions are fixed for better readability.
  BRIGHTNESS_CTRL -> LP855X_BRIGHTNESS_CTRL
  DEVICE_CTRL     -> LP855X_DEVICE_CTRL
  EEPROM_START    -> LP855X_EEPROM_START
  EEPROM_END      -> LP855X_EEPROM_END
  EPROM_START     -> LP8556_EPROM_START
  EPROM_END       -> LP8556_EPROM_END

And LP8557 register definitions are added.  New register function,
lp855x_update_bit() is added.

Signed-off-by: Milo(Woogyom) Kim 
Acked-by: Jingoo Han 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

drivers/video/backlight/lp855x_bl.c: use generic PWM functions

2012-12-18T01:15:16+00:00

The LP855x family devices support the PWM input for the backlight control.
 Period of the PWM is configurable in the platform side.  Platform
specific functions are unnecessary anymore because generic PWM functions
are used inside the driver.

(PWM input mode)
To set the brightness, new lp855x_pwm_ctrl() is used.
If a PWM device is not allocated, devm_pwm_get() is called.
The PWM consumer name is from the chip name such as 'lp8550' and 'lp8556'.
To get the brightness value, no additional handling is required.
Just the value of 'props.brightness' is returned.

If the PWM driver is not ready while initializing the LP855x driver, it's
OK.  The PWM device can be retrieved later, when the brightness value is
changed.

Documentation is updated with an example.

[akpm@linux-foundation.org: coding-style simplification, per Thierry]
Signed-off-by: Milo(Woogyom) Kim 
Cc: Thierry Reding 
Cc: Richard Purdie 
Cc: Bryan Wu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

backlight: new backlight driver for LP855x devices

2012-03-23T23:58:33+00:00

THis driver supports TI LP8550/LP8551/LP8552/LP8553/LP8556 backlight
devices.

The brightness can be controlled by the I2C or PWM input.  The lp855x
driver provides both modes.  For the PWM control, pwm-specific functions
can be defined in the platform data.  And some information can be read
via the sysfs(lp855x device attributes).

For details, please refer to Documentation/backlight/lp855x-driver.txt.

[axel.lin@gmail.com: add missing mutex_unlock in lp855x_read_byte() error path]
[axel.lin@gmail.com: check platform data in lp855x_probe()]
[axel.lin@gmail.com: small cleanups]
[dan.carpenter@oracle.com: silence a compiler warning]
[axel.lin@gmail.com: use id->driver_data to differentiate lp855x chips]
[akpm@linux-foundation.org: simplify boolean return expression]
Signed-off-by: Milo(Woogyom) Kim 
Signed-off-by: Axel Lin 
Signed-off-by: Dan Carpenter 
Cc: Richard Purdie 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds