On Mon, 19 Sep 2016 11:12:12 -0700 Doug Anderson <dianders at chromium.org> wrote: > Hi, > > On Mon, Sep 19, 2016 at 11:06 AM, Boris Brezillon > <boris.brezillon at free-electrons.com> wrote: > > On Mon, 19 Sep 2016 10:52:51 -0700 > > Doug Anderson <dianders at chromium.org> wrote: > > > >> Hi, > >> > >> On Mon, Sep 19, 2016 at 10:48 AM, Boris Brezillon > >> <boris.brezillon at free-electrons.com> wrote: > >> > The PWM chip has always claimed the pins and muxed them to the PWM IP. > >> > So, this means it's broken from the beginning, and my patch is only > >> > uncovering the problem (unless the pins stay configured as input until > >> > the PWM is enabled, which I'm not sure is the case). > >> > >> Such a solution is achievable with the pinctrl APIs pretty easily. > >> You might not be able to use the automatic "init" state but you can do > >> something similar and switch to an "active" state once the PWM is > >> actually turned on the first time. > > > > But is it really the case here (I don't see any code requesting a > > specific pinmux depending on the PWM state)? > > It is not happening right now as far as I know. ...but that's a bug. Okay. > > > Anyway, we really need to handle this case, we should define the > > typical voltage when the PWM is disabled. Same as what you suggested > > with voltage-when-input, but with a different naming (since the concept > > of pinmux is PWM hardware/driver specific). > > > > voltage-when-pwm-disabled = <...>; > > Voltage when disabled and voltage when input are two different states. > A disabled PWM will typically either drive high or low (depending on > where it was when you turned it off). Not all "disabled" states will > mean that the pin is configured as an input. Well, my point was that, from the regulator PoV, a PWM is either enabled or disabled. The pinmux config when the PWM is disabled depends on the PWM driver/hardware, and I don't think it's a good idea to expose this information at the regulator level, hence the name "voltage-when-pwm-disabled". Anyway, let's stop bikeshedding, no matter the name, I think we both agree that a new DT property is needed to handle this case :-).
