On Sun, 05 Jan 2020, Pavel Machek wrote:
Hi!
It would be good to get LED backlight to work in clean way for 5.6 kernel.
As far as I can see, these are neccessary (but not enough; it does not work for me): lm3532 changes to register LED with of node, plus device tree changes for droid 4, and these generic changes:
commit d457d0c97d6d55fe3e62633791ac05d289a37d2e Author: Tomi Valkeinen tomi.valkeinen@ti.com Date: Thu Oct 3 10:28:12 2019 +0200
backlight: add led-backlight driver This patch adds a led-backlight driver (led_bl), which is similar to pwm_bl except the driver uses a LED class driver to adjust the brightness in the HW. Multiple LEDs can be used for a single backlight. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> Acked-by: Pavel Machek <pavel@ucw.cz> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>commit 44b7adbf0b07904e4198ae1d0a763917d1c68a23 Author: Jean-Jacques Hiblot jjhiblot@ti.com Date: Thu Oct 3 10:28:10 2019 +0200
leds: Add managed API to get a LED from a device driver If the LED is acquired by a consumer device with devm_led_get(), it is automatically released when the device is detached. Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Pavel <pavel@ucw.cz>commit 93b98c570d7f898063ab6204e1b3950a3335dd12 Author: Tomi Valkeinen tomi.valkeinen@ti.com Date: Thu Oct 3 10:28:09 2019 +0200
leds: Add of_led_get() and led_put() This patch adds basic support for a kernel driver to get a LED device. This will be used by the led-backlight driver. Only OF version is implemented for now, and the behavior is similar to PWM's of_pwm_get() and pwm_put(). Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Pavel <pavel@ucw.cz>[If you have an idea what else is needed, it would be welcome; it works for me in development tree but not in tree I'd like to upstream.]
Lee, would you be willing to take "backlight: add led-backlight driver"? Would it help if I got "leds: Add managed API to get a LED from a device driver" and "leds: Add of_led_get() and led_put()" into for_next tree of the LED subsystem?
It looks like you have an open question from Tony on v10.
Is that patch orthogonal, or are there depend{ants,encies}?
It is kind of important as, well, phone without screen looks pretty much dead, and same issue hits Droid 4 and Librem 5 phones at least...
Best regards, Pavel