[PATCH 1/2] backlight: gpio_backlight: add new property default-brightness-level

[PATCH 1/2] backlight: gpio_backlight: add new property default-brightness-level

[Alexandru Ardelean]

From: Yannick Fertre <yannick.fertre@foss.st.com>

Add new property to set a brightness by default at probe.

Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>
Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
---

Link to original patch:
  https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98

 drivers/video/backlight/gpio_backlight.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 6f78d928f054..d3fa3a8bef4d 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -53,6 +53,7 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	struct backlight_device *bl;
 	struct gpio_backlight *gbl;
 	int ret, init_brightness, def_value;
+	u32 value;
 
 	gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL);
 	if (gbl == NULL)
@@ -93,7 +94,11 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	else
 		bl->props.power = FB_BLANK_UNBLANK;
 
-	bl->props.brightness = 1;
+	ret = device_property_read_u32(dev, "default-brightness-level", &value);
+	if (!ret && value <= props.max_brightness)
+		bl->props.brightness = value;
+	else
+		bl->props.brightness = 1;
 
 	init_brightness = backlight_get_brightness(bl);
 	ret = gpiod_direction_output(gbl->gpiod, init_brightness);
-- 
2.40.1

[PATCH 2/2] dt-bindings: backlight: document new property default-brightness-level

[Alexandru Ardelean]

From: Yannick Fertre <yannick.fertre@foss.st.com>

Add documentation for new default-brightness-level property.

Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>
Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
---

Link to original patch:
  https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98

 .../bindings/leds/backlight/gpio-backlight.yaml          | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
index 584030b6b0b9..b96c08cff0f0 100644
--- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
+++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
@@ -23,6 +23,15 @@ properties:
     description: enable the backlight at boot.
     type: boolean
 
+  default-brightness-level:
+    description:
+      The default brightness level (index into the array defined by the
+      "brightness-levels" property).
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+dependencies:
+  default-brightness-level: [ "brightness-levels" ]
+
 required:
   - compatible
   - gpios
-- 
2.40.1

Re: [PATCH 2/2] dt-bindings: backlight: document new property default-brightness-level

[Daniel Thompson]

On Fri, May 19, 2023 at 11:05:20PM +0300, Alexandru Ardelean wrote:
> From: Yannick Fertre <yannick.fertre@foss.st.com>
>
> Add documentation for new default-brightness-level property.
>
> Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>
> Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
> ---
>
> Link to original patch:
>   https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98
>
>  .../bindings/leds/backlight/gpio-backlight.yaml          | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> index 584030b6b0b9..b96c08cff0f0 100644
> --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> @@ -23,6 +23,15 @@ properties:
>      description: enable the backlight at boot.
>      type: boolean
>
> +  default-brightness-level:
> +    description:
> +      The default brightness level (index into the array defined by the
> +      "brightness-levels" property).

gpio-backlight does not have a brightness-levels array property!

I think it is also necessary to improve the docs of both properties to
distinguish between the meaning of default-on and
default-brightness-level. The result of setting default-on and
default-brightness level to zero is that the GPIO will be off (this is
correct behaviour but hard to figure out from the current text).

default-on is a control that can "enable" the backlight at boot when it
is not linked to a display in the DT (e.g. it is mostly for legacy
cases). When the backlight is linked to a display then the backlight
enable state will be automatically linked to the display enable state
instead.

default-brightness-level is useful for handling displays that
are still readable with the backlight off (e-ink, reflective/
transflexive LCD, etc), otherwise is should be absent or set to 1.


> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +dependencies:
> +  default-brightness-level: [ "brightness-levels" ]

As above, depending on brightness-levels doesn't make any sense here.


Daniel.

Re: [PATCH 2/2] dt-bindings: backlight: document new property default-brightness-level

[Alexandru Ardelean]

On Fri, May 26, 2023 at 1:20 PM Daniel Thompson
<daniel.thompson@linaro.org> wrote:
>
> On Fri, May 19, 2023 at 11:05:20PM +0300, Alexandru Ardelean wrote:
> > From: Yannick Fertre <yannick.fertre@foss.st.com>
> >
> > Add documentation for new default-brightness-level property.
> >
> > Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>
> > Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> > Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
> > ---
> >
> > Link to original patch:
> >   https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98
> >
> >  .../bindings/leds/backlight/gpio-backlight.yaml          | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> > index 584030b6b0b9..b96c08cff0f0 100644
> > --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> > +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> > @@ -23,6 +23,15 @@ properties:
> >      description: enable the backlight at boot.
> >      type: boolean
> >
> > +  default-brightness-level:
> > +    description:
> > +      The default brightness level (index into the array defined by the
> > +      "brightness-levels" property).
>
> gpio-backlight does not have a brightness-levels array property!
>
> I think it is also necessary to improve the docs of both properties to
> distinguish between the meaning of default-on and
> default-brightness-level. The result of setting default-on and
> default-brightness level to zero is that the GPIO will be off (this is
> correct behaviour but hard to figure out from the current text).
>
> default-on is a control that can "enable" the backlight at boot when it
> is not linked to a display in the DT (e.g. it is mostly for legacy
> cases). When the backlight is linked to a display then the backlight
> enable state will be automatically linked to the display enable state
> instead.
>
> default-brightness-level is useful for handling displays that
> are still readable with the backlight off (e-ink, reflective/
> transflexive LCD, etc), otherwise is should be absent or set to 1.

ack
will do in V2

thanks

>
>
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +
> > +dependencies:
> > +  default-brightness-level: [ "brightness-levels" ]
>
> As above, depending on brightness-levels doesn't make any sense here.
>
>
> Daniel.

Re: [PATCH 2/2] dt-bindings: backlight: document new property default-brightness-level

[Philippe CORNU]

On 5/19/23 22:05, Alexandru Ardelean wrote:
> From: Yannick Fertre <yannick.fertre@foss.st.com>
> 
> Add documentation for new default-brightness-level property.
> 
> Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>

Hi Alexandru,
same comments as for the 1/2 patch.
Many thanks
Philippe :-)

> Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
> ---
> 
> Link to original patch:
>    https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98
> 
>   .../bindings/leds/backlight/gpio-backlight.yaml          | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> index 584030b6b0b9..b96c08cff0f0 100644
> --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> @@ -23,6 +23,15 @@ properties:
>       description: enable the backlight at boot.
>       type: boolean
>   
> +  default-brightness-level:
> +    description:
> +      The default brightness level (index into the array defined by the
> +      "brightness-levels" property).
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +dependencies:
> +  default-brightness-level: [ "brightness-levels" ]
> +
>   required:
>     - compatible
>     - gpios

Re: [PATCH 2/2] dt-bindings: backlight: document new property default-brightness-level

[Alexandru Ardelean]

On Fri, May 26, 2023 at 3:05 PM Philippe CORNU
<philippe.cornu@foss.st.com> wrote:
>
>
>
> On 5/19/23 22:05, Alexandru Ardelean wrote:
> > From: Yannick Fertre <yannick.fertre@foss.st.com>
> >
> > Add documentation for new default-brightness-level property.
> >
> > Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>
>
> Hi Alexandru,
> same comments as for the 1/2 patch.

Ack

Will do
Thanks
Alexandru

> Many thanks
> Philippe :-)
>
> > Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> > Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
> > ---
> >
> > Link to original patch:
> >    https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98
> >
> >   .../bindings/leds/backlight/gpio-backlight.yaml          | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> > index 584030b6b0b9..b96c08cff0f0 100644
> > --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> > +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml
> > @@ -23,6 +23,15 @@ properties:
> >       description: enable the backlight at boot.
> >       type: boolean
> >
> > +  default-brightness-level:
> > +    description:
> > +      The default brightness level (index into the array defined by the
> > +      "brightness-levels" property).
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +
> > +dependencies:
> > +  default-brightness-level: [ "brightness-levels" ]
> > +
> >   required:
> >     - compatible
> >     - gpios

Re: [PATCH 1/2] backlight: gpio_backlight: add new property default-brightness-level

[Daniel Thompson]

On Fri, May 19, 2023 at 11:05:19PM +0300, Alexandru Ardelean wrote:
> From: Yannick Fertre <yannick.fertre@foss.st.com>
>
> Add new property to set a brightness by default at probe.
>
> Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>
> Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>

Patch order should be reversed for v2. Nevertheless:
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


Daniel.

>  	struct backlight_device *bl;
>  	struct gpio_backlight *gbl;
>  	int ret, init_brightness, def_value;
> +	u32 value;
>
>  	gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL);
>  	if (gbl == NULL)
> @@ -93,7 +94,11 @@ static int gpio_backlight_probe(struct platform_device *pdev)
>  	else
>  		bl->props.power = FB_BLANK_UNBLANK;
>
> -	bl->props.brightness = 1;
> +	ret = device_property_read_u32(dev, "default-brightness-level", &value);
> +	if (!ret && value <= props.max_brightness)
> +		bl->props.brightness = value;
> +	else
> +		bl->props.brightness = 1;
>
>  	init_brightness = backlight_get_brightness(bl);
>  	ret = gpiod_direction_output(gbl->gpiod, init_brightness);
> --
> 2.40.1
>

Re: [PATCH 1/2] backlight: gpio_backlight: add new property default-brightness-level

[Philippe CORNU]

On 5/19/23 22:05, Alexandru Ardelean wrote:
> From: Yannick Fertre <yannick.fertre@foss.st.com>
> 
> Add new property to set a brightness by default at probe.
> 
> Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>

Hi Alexandru,

Many thanks for your patch.

You have sent a patch originally pushed on the STMicroelectronics github 
as mentioned in your commit message (no problem with that :-). But, the 
"Reviewed-by" inside this github patch is linked to our gerrit STM 
internal server so you can not use it directly for mainlining this patch.

So please, re-send your this patch without my "Reviewed-by".

Many thanks
Philippe :-)


> Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
> ---
> 
> Link to original patch:
>    https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98
> 
>   drivers/video/backlight/gpio_backlight.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
> index 6f78d928f054..d3fa3a8bef4d 100644
> --- a/drivers/video/backlight/gpio_backlight.c
> +++ b/drivers/video/backlight/gpio_backlight.c
> @@ -53,6 +53,7 @@ static int gpio_backlight_probe(struct platform_device *pdev)
>   	struct backlight_device *bl;
>   	struct gpio_backlight *gbl;
>   	int ret, init_brightness, def_value;
> +	u32 value;
>   
>   	gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL);
>   	if (gbl == NULL)
> @@ -93,7 +94,11 @@ static int gpio_backlight_probe(struct platform_device *pdev)
>   	else
>   		bl->props.power = FB_BLANK_UNBLANK;
>   
> -	bl->props.brightness = 1;
> +	ret = device_property_read_u32(dev, "default-brightness-level", &value);
> +	if (!ret && value <= props.max_brightness)
> +		bl->props.brightness = value;
> +	else
> +		bl->props.brightness = 1;
>   
>   	init_brightness = backlight_get_brightness(bl);
>   	ret = gpiod_direction_output(gbl->gpiod, init_brightness);

Re: [PATCH 1/2] backlight: gpio_backlight: add new property default-brightness-level

[Alexandru Ardelean]

On Fri, May 26, 2023 at 3:04 PM Philippe CORNU
<philippe.cornu@foss.st.com> wrote:
>
>
> On 5/19/23 22:05, Alexandru Ardelean wrote:
> > From: Yannick Fertre <yannick.fertre@foss.st.com>
> >
> > Add new property to set a brightness by default at probe.
> >
> > Reviewed-by: Philippe CORNU <philippe.cornu@foss.st.com>
>
> Hi Alexandru,
>
> Many thanks for your patch.
>
> You have sent a patch originally pushed on the STMicroelectronics github
> as mentioned in your commit message (no problem with that :-). But, the
> "Reviewed-by" inside this github patch is linked to our gerrit STM
> internal server so you can not use it directly for mainlining this patch.
>
> So please, re-send your this patch without my "Reviewed-by".

ack
will do

>
> Many thanks
> Philippe :-)
>
>
> > Signed-off-by: Yannick Fertre <yannick.fertre@foss.st.com>
> > Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>
> > ---
> >
> > Link to original patch:
> >    https://github.com/STMicroelectronics/linux/commit/c4067d7bd883c6fa14ffd49892c4ce663cdafe98
> >
> >   drivers/video/backlight/gpio_backlight.c | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
> > index 6f78d928f054..d3fa3a8bef4d 100644
> > --- a/drivers/video/backlight/gpio_backlight.c
> > +++ b/drivers/video/backlight/gpio_backlight.c
> > @@ -53,6 +53,7 @@ static int gpio_backlight_probe(struct platform_device *pdev)
> >       struct backlight_device *bl;
> >       struct gpio_backlight *gbl;
> >       int ret, init_brightness, def_value;
> > +     u32 value;
> >
> >       gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL);
> >       if (gbl == NULL)
> > @@ -93,7 +94,11 @@ static int gpio_backlight_probe(struct platform_device *pdev)
> >       else
> >               bl->props.power = FB_BLANK_UNBLANK;
> >
> > -     bl->props.brightness = 1;
> > +     ret = device_property_read_u32(dev, "default-brightness-level", &value);
> > +     if (!ret && value <= props.max_brightness)
> > +             bl->props.brightness = value;
> > +     else
> > +             bl->props.brightness = 1;
> >
> >       init_brightness = backlight_get_brightness(bl);
> >       ret = gpiod_direction_output(gbl->gpiod, init_brightness);