[PATCH] backlight: pwm_bl: Don't assign levels table repeatedly

[PATCH] backlight: pwm_bl: Don't assign levels table repeatedly

[Matthias Kaehlcke]

pwm_backlight_probe() re-assigns pb->levels for every brightness
level. This is not needed and was likely not intended, since
neither side of the assignment changes during the loop. Assign
the field only once.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

 drivers/video/backlight/pwm_bl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 746eebc411df..959436b9e92b 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -564,6 +564,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	memset(&props, 0, sizeof(struct backlight_properties));
 
 	if (data->levels) {
+		pb->levels = data->levels;
+
 		/*
 		 * For the DT case, only when brightness levels is defined
 		 * data->levels is filled. For the non-DT case, data->levels
@@ -572,8 +574,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 		for (i = 0; i <= data->max_brightness; i++) {
 			if (data->levels[i] > pb->scale)
 				pb->scale = data->levels[i];
-
-			pb->levels = data->levels;
 		}
 
 		if (pwm_backlight_is_linear(data))
-- 
2.23.0.444.g18eeb5a265-goog

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Re: [PATCH] backlight: pwm_bl: Don't assign levels table repeatedly

[Daniel Thompson]

On Tue, Oct 01, 2019 at 04:29:24PM -0700, Matthias Kaehlcke wrote:
> pwm_backlight_probe() re-assigns pb->levels for every brightness
> level. This is not needed and was likely not intended, since
> neither side of the assignment changes during the loop. Assign
> the field only once.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>

Makes sense but this should probably be dropping the curly braces too.


Daniel.

> ---
> 
>  drivers/video/backlight/pwm_bl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 746eebc411df..959436b9e92b 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -564,6 +564,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  	memset(&props, 0, sizeof(struct backlight_properties));
>  
>  	if (data->levels) {
> +		pb->levels = data->levels;
> +
>  		/*
>  		 * For the DT case, only when brightness levels is defined
>  		 * data->levels is filled. For the non-DT case, data->levels
> @@ -572,8 +574,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  		for (i = 0; i <= data->max_brightness; i++) {
>  			if (data->levels[i] > pb->scale)
>  				pb->scale = data->levels[i];
> -
> -			pb->levels = data->levels;
>  		}
>  
>  		if (pwm_backlight_is_linear(data))
> -- 
> 2.23.0.444.g18eeb5a265-goog
> 

Re: [PATCH] backlight: pwm_bl: Don't assign levels table repeatedly

[Matthias Kaehlcke]

On Wed, Oct 02, 2019 at 11:07:37AM +0100, Daniel Thompson wrote:
> On Tue, Oct 01, 2019 at 04:29:24PM -0700, Matthias Kaehlcke wrote:
> > pwm_backlight_probe() re-assigns pb->levels for every brightness
> > level. This is not needed and was likely not intended, since
> > neither side of the assignment changes during the loop. Assign
> > the field only once.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> 
> Makes sense but this should probably be dropping the curly braces too.

ack, I'll send a new version with the curly braces removed.

> >  drivers/video/backlight/pwm_bl.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> > index 746eebc411df..959436b9e92b 100644
> > --- a/drivers/video/backlight/pwm_bl.c
> > +++ b/drivers/video/backlight/pwm_bl.c
> > @@ -564,6 +564,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> >  	memset(&props, 0, sizeof(struct backlight_properties));
> >  
> >  	if (data->levels) {
> > +		pb->levels = data->levels;
> > +
> >  		/*
> >  		 * For the DT case, only when brightness levels is defined
> >  		 * data->levels is filled. For the non-DT case, data->levels
> > @@ -572,8 +574,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> >  		for (i = 0; i <= data->max_brightness; i++) {
> >  			if (data->levels[i] > pb->scale)
> >  				pb->scale = data->levels[i];
> > -
> > -			pb->levels = data->levels;
> >  		}
> >  
> >  		if (pwm_backlight_is_linear(data))
> > -- 
> > 2.23.0.444.g18eeb5a265-goog
> >