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); 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; 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); mutex_lock(&ddata->lock); -- 2.42.0
