On Wed, 22 Nov 2023, Uwe Kleine-König wrote:
> Hello Lee,
>
> On Wed, Nov 22, 2023 at 11:56:21AM +0000, Lee Jones wrote:
> > 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@xxxxxxxxxxxxxx>
> > > ---
> > > 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;
> > > [...]
> > > @@ -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!
>
> This is indeed one of the uglier conversions. It gets a bit prettier
> with the following addon patch:
>
> diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
> index 283227e02df6..e09eba823057 100644
> --- a/drivers/leds/rgb/leds-qcom-lpg.c
> +++ b/drivers/leds/rgb/leds-qcom-lpg.c
> @@ -206,6 +206,10 @@ struct lpg_data {
> const struct lpg_channel_data *channels;
> };
>
> +struct lpg_pwm_data {
> + struct lpg *lpg;
> +};
> +
> static int triled_set(struct lpg *lpg, unsigned int mask, unsigned int enable)
> {
> /* Skip if we don't have a triled block */
> @@ -979,8 +983,9 @@ static int lpg_pattern_mc_clear(struct led_classdev *cdev)
>
> static inline struct lpg *lpg_pwm_from_chip(struct pwm_chip *chip)
> {
> - struct lpg **lpg = pwmchip_priv(chip);
> - return *lpg;
> + struct lpg_pwm_data *lpg_pwm_data = pwmchip_priv(chip);
> +
> + return lpg_pwm_data->lpg;
> }
>
> static int lpg_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
> @@ -1096,14 +1101,16 @@ static const struct pwm_ops lpg_pwm_ops = {
> static int lpg_add_pwm(struct lpg *lpg)
> {
> struct pwm_chip *chip;
> + struct lpg_pwm_data *lpg_pwm_data;
> int ret;
>
> lpg->pwm = chip = devm_pwmchip_alloc(lpg->dev, lpg->num_channels,
> - sizeof(&lpg));
> + sizeof(*lpg_pwm_data));
> if (IS_ERR(chip))
> return PTR_ERR(chip);
>
> - *(struct lpg **)pwmchip_priv(chip) = lpg;
> + lpg_pwm_data = pwmchip_priv(chip);
> + lpg_pwm_data->lpg = lpg;
>
> chip->ops = &lpg_pwm_ops;
>
> Would you like it better then?
It's definitely nicer to read and more in-line with the style I expect,
but the additional wrapper/abstraction layer is still bothersome.
--
Lee Jones [李琼斯]
