| Message ID | 1546918094-13960-2-git-send-email-yoshihiro.shimoda.uh@renesas.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/4] pwm: rcar: Add support "atomic" API | expand |
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 <yoshihiro.shimoda.uh@renesas.com> > --- > 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
Hello Uwe, Thank you for the review! > From: Uwe Kleine-Konig, Sent: Tuesday, January 8, 2019 4:44 PM <snip> > > +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. This driver only supports normal polarity. So, I'll change the code as the following: /* This HW/driver only support normal polarity */ pwm_get_state(pwm, &cur_state); if (state->polarity != PWM_POLARITY_NORMAL) return -ENOTSUPP; > > + 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. Thank you for the pointing it out. This code is possible to output 66% wave form between the second rcar_pwm_update() and rcar_pwm_disable(). So, I'll fix this. Best regards, Yoshihiro Shimoda > Best regards > Uwe > > -- > Pengutronix e.K. | Uwe Kleine-König | > Industrial Linux Solutions | http://www.pengutronix.de/ |
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; + + 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; + } + + return ret; +} + static const struct pwm_ops rcar_pwm_ops = { .request = rcar_pwm_request, .free = rcar_pwm_free, .config = rcar_pwm_config, .enable = rcar_pwm_enable, .disable = rcar_pwm_disable, + .apply = rcar_pwm_apply, .owner = THIS_MODULE, };
This patch adds support for "atomic" API. Behavior is the same as when using legacy APIs. Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> --- drivers/pwm/pwm-rcar.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+)