Re: [v5 2/2] pwm: sifive: change the PWM controlled LED algorithm

Nylon Chen
2023-11-09T07:02:32Z

Hi, Ping on the series.

Uwe, is there anything more I can do to push the process forward?

Nylon Chen <nylon.chen@sifive.com> 於 2023年10月24日 週二 下午6:19寫道：

>
> 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@sifive.com>
> Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
> ---
> 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
>