On Mon, 20 Jul 2015 10:59:40 +0200 Thierry Reding <[email protected]> wrote:
> On Wed, Jul 01, 2015 at 10:21:57AM +0200, Boris Brezillon wrote: > > Add an ->apply() method to the pwm_ops struct to allow PWM drivers to > > implement atomic update. > > This method will be prefered over the ->enable(), ->disable() and > > ->config() methods if available. > > > > Add the pwm_get_state(), pwm_get_default_state() and pwm_apply_state() > > functions for PWM users to be able to use the atomic update feature. > > > > Note that the pwm_apply_state() does not guarantee the atomicity of the > > update operation, it all depends on the availability and implementation > > of the ->apply() method. > > > > Signed-off-by: Boris Brezillon <[email protected]> > > --- > > drivers/pwm/core.c | 110 > > ++++++++++++++++++++++++++++++++++++++++++++++------ > > include/linux/pwm.h | 26 +++++++++++++ > > 2 files changed, 124 insertions(+), 12 deletions(-) > > > > diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c > > index 30631f5..6dafd8e 100644 > > --- a/drivers/pwm/core.c > > +++ b/drivers/pwm/core.c > > @@ -238,8 +238,9 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, > > unsigned int i; > > int ret; > > > > - if (!chip || !chip->dev || !chip->ops || !chip->ops->config || > > - !chip->ops->enable || !chip->ops->disable || !chip->npwm) > > + if (!chip || !chip->dev || !chip->ops || (!chip->ops->apply && > > + (!chip->ops->config || !chip->ops->enable || > > + !chip->ops->disable)) || !chip->npwm) > > return -EINVAL; > > This is becoming really unreadable, perhaps split it into two checks, or > even split out the sanity check on the ops into a separate function to > make the negations easier to read: > > static bool pwm_ops_check(const struct pwm_ops *ops) > { > /* driver supports legacy, non-atomic operation */ > if (ops->config && ops->enable && ops->disable) > return true; > > /* driver supports atomic operation */ > if (ops->apply) > return true; > > return false; > } > > and then use this: > > if (!chip || !chip->dev || !chip->ops || !chip->npwm) > return -EINVAL; > > if (!pwm_ops_check(chip->ops)) > return -EINVAL; > Sure, I'll change that to make it more readable. > > mutex_lock(&pwm_lock); > > @@ -430,7 +431,17 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, > > int period_ns) > > if (!pwm || duty_ns < 0 || period_ns <= 0 || duty_ns > period_ns) > > return -EINVAL; > > > > - err = pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns); > > + if (pwm->chip->ops->apply) { > > + struct pwm_state state = pwm->state; > > Shouldn't this use pwm_get_state()? Yes, I'll fix all of them [...] > > > + > > + state.enabled = true; > > + err = pwm->chip->ops->apply(pwm->chip, pwm, &state); > > There should be a space between the above two lines. I'll add an empty line. > > > > > +int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state) > > +{ > > + int err = 0; > > + > > + if (!pwm) > > + return -EINVAL; > > + > > + if (!memcmp(state, &pwm->state, sizeof(*state))) > > + return 0; > > + > > + if (pwm->chip->ops->apply) { > > + err = pwm->chip->ops->apply(pwm->chip, pwm, state); > > + if (!err) > > + pwm->state = *state; > > Maybe we want pwm_set_state() for this? I'm not opposed to the addition of the pwm_set_state() function as long as it's a private one: I don't want to let PMW drivers or users mess up with the current PWM state. > > > + } else { > > + /* > > + * FIXME: restore the initial state in case of error. > > + */ > > + if (state->polarity != pwm->state.polarity) { > > + pwm_disable(pwm); > > + err = pwm_set_polarity(pwm, state->polarity); > > + if (err) > > + goto out; > > + } > > + > > + if (state->period != pwm->state.period || > > + state->duty_cycle != pwm->state.duty_cycle) { > > + err = pwm_config(pwm, state->period, state->duty_cycle); > > + if (err) > > + goto out; > > + } > > + > > + if (state->enabled != pwm->state.enabled) { > > + if (state->enabled) > > + err = pwm_enable(pwm); > > + else > > + pwm_disable(pwm); > > + } > > + } > > + > > +out: > > + return err; > > +} > > +EXPORT_SYMBOL_GPL(pwm_apply_state); > > + > > static struct pwm_chip *of_node_to_pwmchip(struct device_node *np) > > { > > struct pwm_chip *chip; > > diff --git a/include/linux/pwm.h b/include/linux/pwm.h > > index b47244a..7e99679 100644 > > --- a/include/linux/pwm.h > > +++ b/include/linux/pwm.h > > @@ -151,6 +151,29 @@ static inline enum pwm_polarity pwm_get_polarity(const > > struct pwm_device *pwm) > > return pwm ? pwm->state.polarity : PWM_POLARITY_NORMAL; > > } > > > > +/* > > + * pwm_apply_state - apply a new state to the PWM device > > + */ > > +int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state); > > If you add kerneldoc, please add it properly. It should start with /** > and you need to list at least the parameters and return value. Yes, I'll fix that. BTW, I remember that you were expecting another name for this function (pwm_update IIRC). -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
