Re: [PATCH v3 102/108] leds: qcom-lpg: Make use of devm_pwmchip_alloc() function

[Lee Jones <lee@kernel.org>]

On Tue, 21 Nov 2023, Uwe Kleine-König wrote:

> This prepares the pwm sub-driver to further changes of the pwm core
> outlined in the commit introducing devm_pwmchip_alloc(). There is no
> intended semantical change and the driver should behave as before.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/leds/rgb/leds-qcom-lpg.c | 30 +++++++++++++++++++++---------
>  1 file changed, 21 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
> index 68d82a682bf6..283227e02df6 100644
> --- a/drivers/leds/rgb/leds-qcom-lpg.c
> +++ b/drivers/leds/rgb/leds-qcom-lpg.c
> @@ -77,7 +77,7 @@ struct lpg {
>  
>  	struct mutex lock;
>  
> -	struct pwm_chip pwm;
> +	struct pwm_chip *pwm;
>  
>  	const struct lpg_data *data;
>  
> @@ -977,9 +977,15 @@ static int lpg_pattern_mc_clear(struct led_classdev *cdev)
>  	return lpg_pattern_clear(led);
>  }
>  
> +static inline struct lpg *lpg_pwm_from_chip(struct pwm_chip *chip)
> +{
> +	struct lpg **lpg = pwmchip_priv(chip);
> +	return *lpg;
> +}

I don't have easy-vis into the other patches, but if this is a common
pattern, perhaps add a generic helper in <linux/pwm.h>?

>  static int lpg_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
>  {
> -	struct lpg *lpg = container_of(chip, struct lpg, pwm);
> +	struct lpg *lpg = lpg_pwm_from_chip(chip);
>  	struct lpg_channel *chan = &lpg->channels[pwm->hwpwm];
>  
>  	return chan->in_use ? -EBUSY : 0;
> @@ -995,7 +1001,7 @@ static int lpg_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
>  static int lpg_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  			 const struct pwm_state *state)
>  {
> -	struct lpg *lpg = container_of(chip, struct lpg, pwm);
> +	struct lpg *lpg = lpg_pwm_from_chip(chip);
>  	struct lpg_channel *chan = &lpg->channels[pwm->hwpwm];
>  	int ret = 0;
>  
> @@ -1026,7 +1032,7 @@ static int lpg_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  static int lpg_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
>  			     struct pwm_state *state)
>  {
> -	struct lpg *lpg = container_of(chip, struct lpg, pwm);
> +	struct lpg *lpg = lpg_pwm_from_chip(chip);
>  	struct lpg_channel *chan = &lpg->channels[pwm->hwpwm];
>  	unsigned int resolution;
>  	unsigned int pre_div;
> @@ -1089,13 +1095,19 @@ static const struct pwm_ops lpg_pwm_ops = {
>  
>  static int lpg_add_pwm(struct lpg *lpg)
>  {
> +	struct pwm_chip *chip;
>  	int ret;
>  
> -	lpg->pwm.dev = lpg->dev;
> -	lpg->pwm.npwm = lpg->num_channels;
> -	lpg->pwm.ops = &lpg_pwm_ops;
> +	lpg->pwm = chip = devm_pwmchip_alloc(lpg->dev, lpg->num_channels,
> +					     sizeof(&lpg));
> +	if (IS_ERR(chip))
> +		return PTR_ERR(chip);
>  
> -	ret = pwmchip_add(&lpg->pwm);
> +	*(struct lpg **)pwmchip_priv(chip) = lpg;

This is vile!

-- 
Lee Jones [李琼斯]