On Fri, Nov 16, 2018 at 08:34:30AM +0100, Lothar Waßmann wrote: > Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> wrote: > > > Hello Thierry, > > > > On Thu, Nov 15, 2018 at 04:25:45PM +0100, Thierry Reding wrote: > > > On Wed, Nov 14, 2018 at 10:51:20PM +0100, Uwe Kleine-König wrote: > > > > On Wed, Nov 14, 2018 at 12:34:49PM +0100, Thierry Reding wrote: > [...] > > > > Also dts writes don't need to lookup the needed GPIO numbers and pinctrl. > > > > > > Just to clarify: I don't think that we need to get the GPIO number > > > involved in this case, because we don't have to reconfigure the pin as > > > GPIO to make this work. The only reason that Michal's proposal did that > > > is because that was believed to be necessary. But if the pin can just be > > > configured with a 100k pull-up, that's enough to pull the pin high when > > > we need it. > > > > Unless the gpio happens to be configured as output at the wrong value. > > Further I'm not sure if the pwm in disabled state actively pulls to 0 > > and if in this state the PU of the pin is good enough to ensure a one > > here. That would need verification first. > > No. You can disable the output driver via pinctrl, so that only the > selected pull-up/down is relevant. The pin function and GPIO register > settings don't matter at all in this case. Is this about DSE=HI-Z in the pad control register? I didn't know about this. I see this exists on i.MX6 but not on i.MX25. Also i.MX51 doesn't seem to have this feature. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
