Re: [PATCH v5 05/16] pwm: lpss: Add pwm_lpss_prepare_enable() helper

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, Jul 17, 2020 at 03:37:42PM +0200, Hans de Goede wrote:
> In the not-enabled -> enabled path pwm_lpss_apply() needs to get a
> runtime-pm reference; and then on any errors it needs to release it
> again.
> 
> This leads to somewhat hard to read code. This commit introduces a new
> pwm_lpss_prepare_enable() helper and moves all the steps necessary for
> the not-enabled -> enabled transition there, so that we can error check
> the entire transition in a single place and only have one pm_runtime_put()
> on failure call site.
> 
> While working on this I noticed that the enabled -> enabled (update
> settings) path was quite similar, so I've added an enable parameter to
> the new pwm_lpss_prepare_enable() helper, which allows using it in that
> path too.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
But see below.

> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/pwm/pwm-lpss.c | 45 ++++++++++++++++++++++++------------------
>  1 file changed, 26 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
> index da9bc3d10104..8a136ba2a583 100644
> --- a/drivers/pwm/pwm-lpss.c
> +++ b/drivers/pwm/pwm-lpss.c
> @@ -122,41 +122,48 @@ static inline void pwm_lpss_cond_enable(struct pwm_device *pwm, bool cond)
>  		pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
>  }
>  
> +static int pwm_lpss_prepare_enable(struct pwm_lpss_chip *lpwm,
> +				   struct pwm_device *pwm,
> +				   const struct pwm_state *state,
> +				   bool enable)
> +{
> +	int ret;
> +
> +	ret = pwm_lpss_is_updating(pwm);
> +	if (ret)
> +		return ret;
> +
> +	pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
> +	pwm_lpss_cond_enable(pwm, enable && lpwm->info->bypass == false);
> +	ret = pwm_lpss_wait_for_update(pwm);
> +	if (ret)
> +		return ret;
> +
> +	pwm_lpss_cond_enable(pwm, enable && lpwm->info->bypass == true);
> +	return 0;
> +}
> +
>  static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  			  const struct pwm_state *state)
>  {
>  	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
> -	int ret;

> +	int ret = 0;

We can avoid this change...

>  	if (state->enabled) {
>  		if (!pwm_is_enabled(pwm)) {
>  			pm_runtime_get_sync(chip->dev);
> -			ret = pwm_lpss_is_updating(pwm);
> -			if (ret) {
> -				pm_runtime_put(chip->dev);
> -				return ret;
> -			}
> -			pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
> -			pwm_lpss_cond_enable(pwm, lpwm->info->bypass == false);
> -			ret = pwm_lpss_wait_for_update(pwm);
> -			if (ret) {
> +			ret = pwm_lpss_prepare_enable(lpwm, pwm, state, true);
> +			if (ret)
>  				pm_runtime_put(chip->dev);
> -				return ret;
> -			}
> -			pwm_lpss_cond_enable(pwm, lpwm->info->bypass == true);
>  		} else {
> -			ret = pwm_lpss_is_updating(pwm);
> -			if (ret)
> -				return ret;
> -			pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
> -			return pwm_lpss_wait_for_update(pwm);

> +			ret = pwm_lpss_prepare_enable(lpwm, pwm, state, false);

...by simple return directly from here. But I admit I haven't seen the next patch yet.

>  		}
>  	} else if (pwm_is_enabled(pwm)) {
>  		pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
>  		pm_runtime_put(chip->dev);
>  	}
>  
> -	return 0;
> +	return ret;
>  }
>  
>  static void pwm_lpss_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> -- 
> 2.26.2
> 

-- 
With Best Regards,
Andy Shevchenko