Hello Pavel, Hello Jacek On 09.02.2017 15:24, Pavel Machek wrote: > Hi! > >>>> This might be a misunderstanding. My patch is not meant to replace >>>> anything for driving the LEDs once the kernel is fully loaded. The LED >>>> subsystem offers quite a lot of possibilities to do this. >>>> >>>> My patch mainly deals with the 'default' state of the LEDs immediately >>>> when the driver gets loaded. >>>> Here is an example: I have a system with a LED named 'RUN' which is >>>> turned on steady by U-Boot (indicating "system booting"). When the >>>> PCA9532 driver loads this LED gets turned off due to initialization. >>>> However I would like it remain lit until later a script will make that >>>> 'RUN' LED blink (indicating "system running"). This script will of >>>> course use the existing LED subsystem to do so. To keep the 'RUN' LED >>>> lit I need the DT property 'default-state' being set to 'PCA9532_KEEP'. >>> >>> It looks like all you need is default-state property. >> >> For the example with keeping the 'RUN' led turned on, yes. However I >> would have to configure PSC and PWM registers to make the 'RUN' LED >> blink, for example. > > Is that really useful? Keeping the state from u-boot until userland can take > control... ok, why not. > > If it is useful, right, you can do it. But it will have to be generic for all > the LEDs, not like this. > > You'll want something like > > default_trigger = blinking; > default_trigger_parameters = < 2 sec on, 1 sec off >; > > or something. You may want to coordinate with the USB LED people, which want > default triggers with parametrs. > > Okay, I absolutely agree with you two. The driver should hide hardware specific details (such as chip registers) as much as possible. My approach does the opposite! I will submit a new version of the patch that should conform much better to existing DT bindings for LEDs. many thanks, Felix
