Hello Nylon, On Tue, Oct 24, 2023 at 06:19:02PM +0800, Nylon Chen wrote: > The `frac` variable represents the pulse inactive time, and the result > of this algorithm is the pulse active time. Therefore, we must reverse the result. > > The reference is SiFive FU740-C000 Manual[0] > > Link: https://sifive.cdn.prismic.io/sifive/1a82e600-1f93-4f41-b2d8-86ed8b16acba_fu740-c000-manual-v1p6.pdf [0] > > Signed-off-by: Nylon Chen <nylon.chen@xxxxxxxxxx> > Signed-off-by: Vincent Chen <vincent.chen@xxxxxxxxxx> > --- > drivers/pwm/pwm-sifive.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c > index eabddb7c7820..353c2342fbf1 100644 > --- a/drivers/pwm/pwm-sifive.c > +++ b/drivers/pwm/pwm-sifive.c > @@ -101,7 +101,7 @@ static void pwm_sifive_update_clock(struct pwm_sifive_ddata *ddata, > > /* As scale <= 15 the shift operation cannot overflow. */ > num = (unsigned long long)NSEC_PER_SEC << (PWM_SIFIVE_CMPWIDTH + scale); > - ddata->real_period = div64_ul(num, rate); > + ddata->real_period = DIV_ROUND_UP_ULL(num, rate); It's unclear to me, why you changed that. > dev_dbg(ddata->chip.dev, > "New real_period = %u ns\n", ddata->real_period); > } > @@ -121,13 +121,14 @@ static int pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm, > state->enabled = false; > > state->period = ddata->real_period; > + > + duty = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - duty; I would have placed that directly after duty = readl(...); which then also influences state->enabled = duty > 0; (as it should?). > state->duty_cycle = > (u64)duty * ddata->real_period >> PWM_SIFIVE_CMPWIDTH; > - state->polarity = PWM_POLARITY_INVERSED; > + state->polarity = PWM_POLARITY_NORMAL; > > return 0; > } > - > static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, > const struct pwm_state *state) > { > @@ -139,7 +140,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, > int ret = 0; > u32 frac; > > - if (state->polarity != PWM_POLARITY_INVERSED) > + if (state->polarity != PWM_POLARITY_NORMAL) > return -EINVAL; > > cur_state = pwm->state; > @@ -158,6 +159,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, > num = (u64)duty_cycle * (1U << PWM_SIFIVE_CMPWIDTH); > frac = DIV64_U64_ROUND_CLOSEST(num, state->period); > /* The hardware cannot generate a 100% duty cycle */ > + frac = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - frac; > frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1); frac can only be > (1U << PWM_SIFIVE_CMPWIDTH) - 1 if an overflow happend the line above. Is that what you want here? > mutex_lock(&ddata->lock); Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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