[v8,0/5] Add a generic driver for LED-based backlight

Message

Jean-Jacques Hiblot Oct. 3, 2019, 8:28 a.m. UTC

This series aims to add a led-backlight driver, similar to pwm-backlight,
but using a LED class device underneath.

A few years ago (2015), Tomi Valkeinen posted a series implementing a
backlight driver on top of a LED device:
https://patchwork.kernel.org/patch/7293991/
https://patchwork.kernel.org/patch/7294001/
https://patchwork.kernel.org/patch/7293981/

The discussion stopped because Tomi lacked the time to work on it.

changes in v8:
- use class_find_device_by_of_node() instead of class_find_device()
- renamed devm_led_get() as devm_of_led_get()

changes in v7:
- rebased on top of linux-leds/for-next
- populate the of_node member of the LED device if fwnode is a of_node
  (this is a new patch and the first of the series).
- devm_led_get() works only when the device tree is used. Add a few checks
  for that.  

changes in v6:
- trim the list of included headers
- remove useless definition of BKL_FULL_BRIGHTNESS

changes in v5:
- removed LED brightness scaling
- disable sysfs the interface of the LEDs when used by the backlight device

changes in v4:
- fix dev_err() messages and commit logs following the advices of Pavel
- cosmetic changes (indents, getting rid of  "? 1 : 0" in
  led_match_led_node())

changes in v3:
- dt binding: don't limit the brightness range to 0-255. Use the range of
  the underlying LEDs. as a side-effect, all LEDs must now have the same
  range
- driver: Adapt to dt binding update.
- driver: rework probe() for clarity and remove the remaining goto.

changes in v2:
- handle more than one LED.
- don't make the backlight device a child of the LED controller.
- make brightness-levels and default-brightness-level optional
- removed the option to use a GPIO enable.
- removed the option to use a regulator. It should be handled by the LED
  core
- don't make any change to the LED core (not needed anymore)

Jean-Jacques Hiblot (3):
  leds: populate the device's of_node when possible
  leds: Add managed API to get a LED from a device driver
  dt-bindings: backlight: Add led-backlight binding

Tomi Valkeinen (2):
  leds: Add of_led_get() and led_put()
  backlight: add led-backlight driver

 .../bindings/leds/backlight/led-backlight.txt |  28 ++
 drivers/leds/led-class.c                      |  98 ++++++-
 drivers/video/backlight/Kconfig               |   7 +
 drivers/video/backlight/Makefile              |   1 +
 drivers/video/backlight/led_bl.c              | 260 ++++++++++++++++++
 include/linux/leds.h                          |   6 +
 6 files changed, 399 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
 create mode 100644 drivers/video/backlight/led_bl.c

Comments

Lee Jones Oct. 3, 2019, 11:40 a.m. UTC | #1

On Thu, 03 Oct 2019, Jean-Jacques Hiblot wrote:

> This series aims to add a led-backlight driver, similar to pwm-backlight,
> but using a LED class device underneath.
> 
> A few years ago (2015), Tomi Valkeinen posted a series implementing a
> backlight driver on top of a LED device:
> https://patchwork.kernel.org/patch/7293991/
> https://patchwork.kernel.org/patch/7294001/
> https://patchwork.kernel.org/patch/7293981/
> 
> The discussion stopped because Tomi lacked the time to work on it.

[...]

>  .../bindings/leds/backlight/led-backlight.txt |  28 ++
>  drivers/leds/led-class.c                      |  98 ++++++-
>  drivers/video/backlight/Kconfig               |   7 +
>  drivers/video/backlight/Makefile              |   1 +
>  drivers/video/backlight/led_bl.c              | 260 ++++++++++++++++++
>  include/linux/leds.h                          |   6 +
>  6 files changed, 399 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
>  create mode 100644 drivers/video/backlight/led_bl.c

How should this set be processed?  I'm happy to take it through
Backlight via an immutable branch and PR to be consumed by LED.

Pavel Machek Oct. 8, 2019, 7:55 p.m. UTC | #2

On Thu 2019-10-03 12:40:28, Lee Jones wrote:
> On Thu, 03 Oct 2019, Jean-Jacques Hiblot wrote:
> 
> > This series aims to add a led-backlight driver, similar to pwm-backlight,
> > but using a LED class device underneath.
> > 
> > A few years ago (2015), Tomi Valkeinen posted a series implementing a
> > backlight driver on top of a LED device:
> > https://patchwork.kernel.org/patch/7293991/
> > https://patchwork.kernel.org/patch/7294001/
> > https://patchwork.kernel.org/patch/7293981/
> > 
> > The discussion stopped because Tomi lacked the time to work on it.
> 
> [...]
> 
> >  .../bindings/leds/backlight/led-backlight.txt |  28 ++
> >  drivers/leds/led-class.c                      |  98 ++++++-
> >  drivers/video/backlight/Kconfig               |   7 +
> >  drivers/video/backlight/Makefile              |   1 +
> >  drivers/video/backlight/led_bl.c              | 260 ++++++++++++++++++
> >  include/linux/leds.h                          |   6 +
> >  6 files changed, 399 insertions(+), 1 deletion(-)
> >  create mode 100644 Documentation/devicetree/bindings/leds/backlight/led-backlight.txt
> >  create mode 100644 drivers/video/backlight/led_bl.c
> 
> How should this set be processed?  I'm happy to take it through
> Backlight via an immutable branch and PR to be consumed by LED.

That would make sense to me.

For the record, series is Tested-by: Pavel Machek <[e-mail]> .

Best regards,
									Pavel