| Message ID | 20191004133207.6663-4-linux@rasmusvillemoes.dk |
|---|---|
| State | Accepted |
| Headers | show |
| Series | pwm: mxs: add support for setting polarity via DT | expand |
On Fri, Oct 04, 2019 at 03:32:04PM +0200, Rasmus Villemoes wrote: > If I'm reading of_pwm_xlate_with_flags() right, existing device trees > that set #pwm-cells = 2 will continue to work. Yes, that's what I expect, too. > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> > --- > drivers/pwm/pwm-mxs.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c > index 5a6835e18fc6..57562221c439 100644 > --- a/drivers/pwm/pwm-mxs.c > +++ b/drivers/pwm/pwm-mxs.c > @@ -25,8 +25,11 @@ > #define PERIOD_PERIOD(p) ((p) & 0xffff) > #define PERIOD_PERIOD_MAX 0x10000 > #define PERIOD_ACTIVE_HIGH (3 << 16) > +#define PERIOD_ACTIVE_LOW (2 << 16) > +#define PERIOD_INACTIVE_HIGH (3 << 18) > #define PERIOD_INACTIVE_LOW (2 << 18) > #define PERIOD_POLARITY_NORMAL (PERIOD_ACTIVE_HIGH | PERIOD_INACTIVE_LOW) > +#define PERIOD_POLARITY_INVERSE (PERIOD_ACTIVE_LOW | PERIOD_INACTIVE_HIGH) > #define PERIOD_CDIV(div) (((div) & 0x7) << 20) > #define PERIOD_CDIV_MAX 8 > > @@ -50,9 +53,7 @@ static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > unsigned int period_cycles, duty_cycles; > unsigned long rate; > unsigned long long c; > - > - if (state->polarity != PWM_POLARITY_NORMAL) > - return -ENOTSUPP; > + unsigned int pol_bits; > > /* > * If the PWM channel is disabled, make sure to turn on the > @@ -91,9 +92,12 @@ static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > * only take effect at the beginning of a new period, avoiding > * glitches. > */ > + > + pol_bits = state->polarity == PWM_POLARITY_NORMAL ? > + PERIOD_POLARITY_NORMAL : PERIOD_POLARITY_INVERSE; > writel(duty_cycles << 16, > mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20); > - writel(PERIOD_PERIOD(period_cycles) | PERIOD_POLARITY_NORMAL | PERIOD_CDIV(div), > + writel(PERIOD_PERIOD(period_cycles) | pol_bits | PERIOD_CDIV(div), > mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20); Is the avoidance of glitches still true when period changes? I assume that yes, but I wonder if you tested that. Best regards Uwe
diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c index 5a6835e18fc6..57562221c439 100644 --- a/drivers/pwm/pwm-mxs.c +++ b/drivers/pwm/pwm-mxs.c @@ -25,8 +25,11 @@ #define PERIOD_PERIOD(p) ((p) & 0xffff) #define PERIOD_PERIOD_MAX 0x10000 #define PERIOD_ACTIVE_HIGH (3 << 16) +#define PERIOD_ACTIVE_LOW (2 << 16) +#define PERIOD_INACTIVE_HIGH (3 << 18) #define PERIOD_INACTIVE_LOW (2 << 18) #define PERIOD_POLARITY_NORMAL (PERIOD_ACTIVE_HIGH | PERIOD_INACTIVE_LOW) +#define PERIOD_POLARITY_INVERSE (PERIOD_ACTIVE_LOW | PERIOD_INACTIVE_HIGH) #define PERIOD_CDIV(div) (((div) & 0x7) << 20) #define PERIOD_CDIV_MAX 8 @@ -50,9 +53,7 @@ static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, unsigned int period_cycles, duty_cycles; unsigned long rate; unsigned long long c; - - if (state->polarity != PWM_POLARITY_NORMAL) - return -ENOTSUPP; + unsigned int pol_bits; /* * If the PWM channel is disabled, make sure to turn on the @@ -91,9 +92,12 @@ static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, * only take effect at the beginning of a new period, avoiding * glitches. */ + + pol_bits = state->polarity == PWM_POLARITY_NORMAL ? + PERIOD_POLARITY_NORMAL : PERIOD_POLARITY_INVERSE; writel(duty_cycles << 16, mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20); - writel(PERIOD_PERIOD(period_cycles) | PERIOD_POLARITY_NORMAL | PERIOD_CDIV(div), + writel(PERIOD_PERIOD(period_cycles) | pol_bits | PERIOD_CDIV(div), mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20); if (state->enabled) { @@ -135,6 +139,8 @@ static int mxs_pwm_probe(struct platform_device *pdev) mxs->chip.dev = &pdev->dev; mxs->chip.ops = &mxs_pwm_ops; + mxs->chip.of_xlate = of_pwm_xlate_with_flags; + mxs->chip.of_pwm_n_cells = 3; mxs->chip.base = -1; ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
If I'm reading of_pwm_xlate_with_flags() right, existing device trees that set #pwm-cells = 2 will continue to work. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- drivers/pwm/pwm-mxs.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)