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] Co-developed-by: Zong Li <zong.li@xxxxxxxxxx> Signed-off-by: Zong Li <zong.li@xxxxxxxxxx> Co-developed-by: Vincent Chen <vincent.chen@xxxxxxxxxx> Signed-off-by: Vincent Chen <vincent.chen@xxxxxxxxxx> Signed-off-by: Nylon Chen <nylon.chen@xxxxxxxxxx> --- drivers/pwm/pwm-sifive.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index d5b647e6be78..bb9146267bc5 100644 --- a/drivers/pwm/pwm-sifive.c +++ b/drivers/pwm/pwm-sifive.c @@ -110,9 +110,10 @@ static int pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state) { struct pwm_sifive_ddata *ddata = pwm_sifive_chip_to_ddata(chip); - u32 duty, val; + u32 duty, val, inactive; - duty = readl(ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + inactive = readl(ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + duty = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - inactive; state->enabled = duty > 0; @@ -123,7 +124,7 @@ static int pwm_sifive_get_state(struct pwm_chip *chip, struct pwm_device *pwm, state->period = ddata->real_period; state->duty_cycle = (u64)duty * ddata->real_period >> PWM_SIFIVE_CMPWIDTH; - state->polarity = PWM_POLARITY_INVERSED; + state->polarity = PWM_POLARITY_NORMAL; return 0; } @@ -137,9 +138,9 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, unsigned long long num; bool enabled; int ret = 0; - u32 frac; + u32 frac, inactive; - if (state->polarity != PWM_POLARITY_INVERSED) + if (state->polarity != PWM_POLARITY_NORMAL) return -EINVAL; cur_state = pwm->state; @@ -157,8 +158,9 @@ 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 */ + /* The hardware cannot generate a 0% duty cycle */ frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1); + inactive = (1U << PWM_SIFIVE_CMPWIDTH) - 1 - frac; mutex_lock(&ddata->lock); if (state->period != ddata->approx_period) { @@ -190,7 +192,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm, } } - writel(frac, ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); + writel(inactive, ddata->regs + PWM_SIFIVE_PWMCMP(pwm->hwpwm)); if (!state->enabled) clk_disable(ddata->clk); -- 2.34.1
