Messages in this thread | | | Date | Thu, 12 Mar 2020 13:22:13 +0100 | From | Pascal Roeleven <> | Subject | pwm: sun4i: pwm-backlight not working since 5.6-rc1 |
| |
Hi all,
I am working on adding an old A10 device to mainline and noticed an issue when testing on 5.5.8 vs master.
Since 5.6-rc1, I can't control the brightness of my LCD backlight anymore. The backlight stays on full brightness instead. I am controlling the brightness value via sysfs for testing.
I am not sure if this is a general pwm-sun4i issue or if it is related to the backlight. However I narrowed it down to one commit for pwm-sun4i:
fa4d81784681a26bcf7d2a43c6ac5cf991ef28f5
If I use pwm-sun4i.c from 5b090b430d750961305030232314b6acdb0102aa on master, the backlight works fine. Unfortunately, due to my lack of kernel experience, I can't see how the commit above broke it.
Not sure if it helps, but the binding for the backlight is as follows:
backlight: backlight { compatible = "pwm-backlight"; pwms = <&pwm 0 100000 PWM_POLARITY_INVERTED>; power-supply = <®_vbat>; enable-gpios = <&pio 7 7 GPIO_ACTIVE_HIGH>; /* PH7 */ brightness-levels = <0 30 40 50 60 70 80 90 100>; default-brightness-level = <8>; };
Please let me know if there is anything else which might be helpful to know or anything I can test.
Regards, Pascal
| |