Hello, On Fri, Oct 04, 2019 at 03:32:02PM +0200, Rasmus Villemoes wrote: > In preparation for supporting setting the polarity, switch the driver > to support the ->apply method. > > Signed-off-by: Rasmus Villemoes <[email protected]> > --- > drivers/pwm/pwm-mxs.c | 70 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 70 insertions(+) > > diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c > index b14376b47ac8..10efd3de0bb3 100644 > --- a/drivers/pwm/pwm-mxs.c > +++ b/drivers/pwm/pwm-mxs.c > @@ -26,6 +26,7 @@ > #define PERIOD_PERIOD_MAX 0x10000 > #define PERIOD_ACTIVE_HIGH (3 << 16) > #define PERIOD_INACTIVE_LOW (2 << 18) > +#define PERIOD_POLARITY_NORMAL (PERIOD_ACTIVE_HIGH | > PERIOD_INACTIVE_LOW) > #define PERIOD_CDIV(div) (((div) & 0x7) << 20) > #define PERIOD_CDIV_MAX 8 > > @@ -41,6 +42,74 @@ struct mxs_pwm_chip { > > #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip) > > +static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > + const struct pwm_state *state) > +{ > + struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); > + int ret, div = 0; > + unsigned int period_cycles, duty_cycles; > + unsigned long rate; > + unsigned long long c; > + > + if (state->polarity != PWM_POLARITY_NORMAL) > + return -ENOTSUPP; > + > + /* > + * If the PWM channel is disabled, make sure to turn on the > + * clock before calling clk_get_rate() and writing to the > + * registers. Otherwise, just keep it enabled. > + */ > + if (!pwm_is_enabled(pwm)) { > + ret = clk_prepare_enable(mxs->clk); > + if (ret) > + return ret; > + } > + > + if (!state->enabled && pwm_is_enabled(pwm)) > + writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR);
@Thierry: I wonder if it would be beneficial to stop the calculation of register contents if !state->enabled here. The only drawback (I'm aware) is that pwm_get_state won't return the previously set .period and .duty_cycle. (I also wonder if we should return (e.g.) .duty = 0, .period = 1 in pwm_get_state() if the PWM is off.) For the patch (which is orthogonal regarding the above question): Reviewed-by: Uwe Kleine-König <[email protected]> Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
