On Mon, 09 Apr 2018, Enric Balletbo i Serra wrote: > Dear all, > > This series is a third patchset (resend )integrating the requested > changes. > > The first and second patch what tries to solve is the problem of > granularity for high resolution PWMs. The idea is simple interpolate > between 2 brightness values so we can have a high PWM duty cycle (a > 16 bits PWM is up to 65535 possible steps) without having to list > out every possible value in the dts. I think that this patch is > required to not break backward compatibility, to be more flexible and > also extend the functionality to be able to use high resolution PWM > with enough steps to have a good UI experience in userspace. > > The thirth and fourth patch is a bit more ambicious, the idea is let > decide the driver the brightness-levels required in function of the PWM > resolution. To do this create a brightness-levels table filled with the > CIE 1931 algorithm values to convert brightness to PWM duty cycle. > > More detailed info is available in the commit message of every patch. > > Both functionalities were tested on a Samsung Chromebook Plus (that has > a 16 bits PWM) and a SL50 device (with a 8 bits PWM) > > Waiting for your feedback. > > Best regards > > Enric Balletbo i Serra (4): > backlight: pwm_bl: linear interpolation between brightness-levels > dt-bindings: pwm-backlight: add a num-interpolation-steps property. > backlight: pwm_bl: compute brightness of LED linearly to human eye. > dt-bindings: pwm-backlight: move brightness-levels to optional. > > .../bindings/leds/backlight/pwm-backlight.txt | 34 ++- > drivers/video/backlight/pwm_bl.c | 232 +++++++++++++++++++-- > 2 files changed, 246 insertions(+), 20 deletions(-) All applied for v4.18, thanks. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
