Hello,
On Tue, Jan 08, 2019 at 12:28:11PM +0900, Yoshihiro Shimoda wrote:
> This patch adds support for "atomic" API. Behavior is the same as
> when using legacy APIs.
>
> Signed-off-by: Yoshihiro Shimoda <[email protected]>
> ---
> drivers/pwm/pwm-rcar.c | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/drivers/pwm/pwm-rcar.c b/drivers/pwm/pwm-rcar.c
> index a41812f..ba70e83 100644
> --- a/drivers/pwm/pwm-rcar.c
> +++ b/drivers/pwm/pwm-rcar.c
> @@ -192,12 +192,49 @@ static void rcar_pwm_disable(struct pwm_chip *chip,
> struct pwm_device *pwm)
> rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
> }
>
> +static int rcar_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + struct pwm_state *state)
> +{
> + struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
> + struct pwm_state cur_state;
> + int div, ret;
> +
> + /* This HW doesn't support changing polarity */
> + pwm_get_state(pwm, &cur_state);
> + if (state->polarity != cur_state.polarity)
> + return -ENOTSUPP;
Does the driver only support normal polarity or only inversed polarity?
If so checking against that would be more clear here.
> +
> + div = rcar_pwm_get_clock_division(rp, state->period);
> + if (div < 0)
> + return div;
> +
> + rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
> +
> + ret = rcar_pwm_set_counter(rp, div, state->duty_cycle, state->period);
> + if (!ret)
> + rcar_pwm_set_clock_control(rp, div);
> +
> + /* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
> + rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);
> +
> + if (!ret && state->enabled)
> + ret = rcar_pwm_enable(chip, pwm);
> +
> + if (!state->enabled) {
> + rcar_pwm_disable(chip, pwm);
> + ret = 0;
> + }
Assume the PWM runs with duty cycle 33% when
pwm_apply_state({ .enabled=0, .duty_cycle=66, .period=100 }) is called.
Does this might result in a 66% wave form being emitted? If yes, this
needs fixing.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
