On Mon, Sep 02, 2019 at 04:32:31PM +0200, Uwe Kleine-König wrote: > On Fri, Aug 30, 2019 at 07:48:35PM +0200, Heiko Stuebner wrote: > > Am Samstag, 24. August 2019, 17:37:03 CEST schrieb Uwe Kleine-König: > > > --- > > > drivers/pwm/core.c | 9 ++++++++- > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c > > > index 72347ca4a647..92333b89bf02 100644 > > > --- a/drivers/pwm/core.c > > > +++ b/drivers/pwm/core.c > > > @@ -473,7 +473,14 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) > > > if (err) > > > return err; > > > > > > - pwm->state = *state; > > > + /* > > > + * .apply might have to round some values in *state, if possible > > > + * read the actually implemented value back. > > > + */ > > > + if (chip->ops->get_state) > > > + chip->ops->get_state(chip, pwm, &pwm->state); > > > + else > > > + pwm->state = *state; > > > > This should probably become > > >- pwm->state = *state; > > > + > > > + /* > > > + * .apply might have to round some values in *state, if possible > > > + * read the actually implemented value back. > > > + */ > > > + if (chip->ops->get_state) > > > + chip->ops->get_state(chip, pwm, &pwm->state); > > > > so always initialize the state to the provided one and then let the driver > > override values? > > This feels wrong. There is another thread that adds a developer knob > that emits some warnings. Catching this kind of error with it would be a > good idea IMHO. > > > The inversion case stems from the Rockchip pwm driver (wrongly?) only > > setting the polarity field when actually inverted, so here the polarity field > > probably never actually got set at all. > > > > But while we should probably fix the rockchip driver to set polarity all the > > time, this is still being true for possible future state-fields, which also > > wouldn't get initialzed from all drivers, which might need an adaption > > first? > > Actually I would prefer that all drivers do it right and rely on this. FTR: I sent a patch for the rockchip driver to do the right thing here. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | _______________________________________________ Linux-rockchip mailing list Linux-rockchip@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-rockchip
