Hi, I'm working on adding support for a device which is booted from a device tree only. Currently this gets me to a login prompt on a serial console and the device is basically functional. However, the device also has a display with a backlight that is controlled via a PWM (supplied by the SoC). If this was a regular board it would be simple to implement this via the pwm-backlight driver.
Unfortunately, the pwm-backlight driver doesn't have device tree support yet and I'm not sure how to best implement it. As far as I can see, I would first need to have some way of representing a PWM device in the DT that I could reference in the pwm-backlight device node and I would need to add actual DT support to pwm-backlight. Implementing support for the data passed in the platform data should be rather straightforward, but I don't see how the callback functions could be represented in the DT. For some setups it would probably be enough to just specify the used PWM, but other boards fiddle with some GPIOs in the callbacks and I guess that could be represented by adding a "gpios" property with a list of pins that need to be toggled for example when the backlight power is enabled/disabled. Has anyone done something similar yet? Am I even on the right track here? Thierry
pgpqPCucGRSmw.pgp
Description: PGP signature
_______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
