# \[PATCH v3 0/2\] backlight\_lm3630a: add enable\_gpios property

- Subsystems: FRAMEBUFFER LAYER, BACKLIGHT CLASS/SUBSYSTEM, LED SUBSYSTEM, OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS, THE REST
- Maintainers: Helge Deller, Lee Jones, Daniel Thompson, Jingoo Han, Pavel Machek, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
- Series: 2 patches touching 2 files, +14/-0
- Status: SUPERSEDED (Superseded by v4 posted 2019-09-12)
- Superseded by v4 (posted 2019-09-12).
- Revision v3 (4 revisions archived).
- List: linux-fbdev
- 8 messages, 3 authors
- Page: https://ratatoskr.run/linux-fbdev/2019/09/5714980/t

## \[PATCH v3 0/2\] backlight\_lm3630a: add enable\_gpios property

- From: Andreas Kemnade \<andreas@kemnade.info\>
- Date: 2019-09-11 17:21:30 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5714980.md

```text
To be able to handle the HWEN pin of the lm3630a, add
an enable gpio to the driver and a property.

Tested on Kobo Clara HD.

Changes in v2:
simplification and reordering

Changes in v3:
added acked-by
removed legacy include

Andreas Kemnade (2):
  dt-bindings: backlight: lm3630a: add enable_gpios
  backlight: lm3630a: add an enable gpio for the HWEN pin

 .../bindings/leds/backlight/lm3630a-backlight.yaml       | 5 +++++
 drivers/video/backlight/lm3630a_bl.c                     | 9 +++++++++
 2 files changed, 14 insertions(+)

-- 
2.20.1
```

## \[PATCH v3 1/2\] dt-bindings: backlight: lm3630a: add enable\_gpios

- From: Andreas Kemnade \<andreas@kemnade.info\>
- Date: 2019-09-11 17:21:36 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5714981.md

```text
add enable-gpios to describe HWEN pin

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Daniel Thompson <redacted>
---
changes in v2: added example
changes in v3: added Acked-by
 .../bindings/leds/backlight/lm3630a-backlight.yaml           | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
index dc129d9a329e..1fa83feffe16 100644
--- a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
+++ b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
@@ -29,6 +29,10 @@ properties:
   '#size-cells':
     const: 0
 
+  enable-gpios:
+    description: GPIO to use to enable/disable the backlight (HWEN pin).
+    maxItems: 1
+
 required:
   - compatible
   - reg
@@ -92,6 +96,7 @@ examples:
     i2c {
         #address-cells = <1>;
         #size-cells = <0>;
+        enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;
 
         led-controller@38 {
                 compatible = "ti,lm3630a";
-- 
2.20.1
```

## \[PATCH v3 2/2\] backlight: lm3630a: add an enable gpio for the HWEN pin

- From: Andreas Kemnade \<andreas@kemnade.info\>
- Date: 2019-09-11 17:21:39 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5714982.md

```text
For now just enable it in the probe function to allow i2c
access. Disabling also means resetting the register values
to default and according to the datasheet does not give
power savings.

Tested on Kobo Clara HD.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
changes in v2:
- simplification
- correct gpio direction initialisation

changes in v3:
- removed legacy include

 drivers/video/backlight/lm3630a_bl.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
index 8f84f3684f04..d9e67b9b2571 100644
--- a/drivers/video/backlight/lm3630a_bl.c
+++ b/drivers/video/backlight/lm3630a_bl.c
@@ -12,6 +12,7 @@
 #include <linux/uaccess.h>
 #include <linux/interrupt.h>
 #include <linux/regmap.h>
+#include <linux/gpio/consumer.h>
 #include <linux/pwm.h>
 #include <linux/platform_data/lm3630a_bl.h>
 
@@ -48,6 +49,7 @@ struct lm3630a_chip {
 	struct lm3630a_platform_data *pdata;
 	struct backlight_device *bleda;
 	struct backlight_device *bledb;
+	struct gpio_desc *enable_gpio;
 	struct regmap *regmap;
 	struct pwm_device *pwmd;
 };
@@ -535,6 +537,13 @@ static int lm3630a_probe(struct i2c_client *client,
 	}
 	pchip->pdata = pdata;
 
+	pchip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable",
+						GPIOD_OUT_HIGH);
+	if (IS_ERR(pchip->enable_gpio)) {
+		rval = PTR_ERR(pchip->enable_gpio);
+		return rval;
+	}
+
 	/* chip initialize */
 	rval = lm3630a_chip_init(pchip);
 	if (rval < 0) {
-- 
2.20.1
```

## Re: \[PATCH v3 2/2\] backlight: lm3630a: add an enable gpio for the HWEN pin

- From: Daniel Thompson \<hidden\>
- Date: 2019-09-12 09:38:29 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5715402.md

```text
On Wed, Sep 11, 2019 at 07:21:06PM +0200, Andreas Kemnade wrote:
> For now just enable it in the probe function to allow i2c
> access. Disabling also means resetting the register values
> to default and according to the datasheet does not give
> power savings.
> 
> Tested on Kobo Clara HD.
> 
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>

Make sure Dan is happy w.r.t. his review comments but if this driver is
unchanged when you spin v4 (for the DT changes) then feel free to add:

Reviewed-by: Daniel Thompson <redacted>


Daniel.

> ---
> changes in v2:
> - simplification
> - correct gpio direction initialisation
> 
> changes in v3:
> - removed legacy include
> 
>  drivers/video/backlight/lm3630a_bl.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> index 8f84f3684f04..d9e67b9b2571 100644
> --- a/drivers/video/backlight/lm3630a_bl.c
> +++ b/drivers/video/backlight/lm3630a_bl.c
> @@ -12,6 +12,7 @@
>  #include <linux/uaccess.h>
>  #include <linux/interrupt.h>
>  #include <linux/regmap.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/pwm.h>
>  #include <linux/platform_data/lm3630a_bl.h>
>  
> @@ -48,6 +49,7 @@ struct lm3630a_chip {
>  	struct lm3630a_platform_data *pdata;
>  	struct backlight_device *bleda;
>  	struct backlight_device *bledb;
> +	struct gpio_desc *enable_gpio;
>  	struct regmap *regmap;
>  	struct pwm_device *pwmd;
>  };
> @@ -535,6 +537,13 @@ static int lm3630a_probe(struct i2c_client *client,
>  	}
>  	pchip->pdata = pdata;
>  
> +	pchip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable",
> +						GPIOD_OUT_HIGH);
> +	if (IS_ERR(pchip->enable_gpio)) {
> +		rval = PTR_ERR(pchip->enable_gpio);
> +		return rval;
> +	}
> +
>  	/* chip initialize */
>  	rval = lm3630a_chip_init(pchip);
>  	if (rval < 0) {
> -- 
> 2.20.1
> 
```

## Re: \[PATCH v3 1/2\] dt-bindings: backlight: lm3630a: add enable\_gpios

- From: Dan Murphy \<hidden\>
- Date: 2019-09-12 11:40:23 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5715514.md

```text
Andreas

On 9/11/19 12:21 PM, Andreas Kemnade wrote:
> add enable-gpios to describe HWEN pin
>
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> Acked-by: Daniel Thompson <redacted>
> ---
> changes in v2: added example
> changes in v3: added Acked-by
>   .../bindings/leds/backlight/lm3630a-backlight.yaml           | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
> index dc129d9a329e..1fa83feffe16 100644
> --- a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
> +++ b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
> @@ -29,6 +29,10 @@ properties:
>     '#size-cells':
>       const: 0
>   
> +  enable-gpios:
> +    description: GPIO to use to enable/disable the backlight (HWEN pin).
> +    maxItems: 1
> +
>   required:
>     - compatible
>     - reg
> @@ -92,6 +96,7 @@ examples:
>       i2c {
>           #address-cells = <1>;
>           #size-cells = <0>;
> +        enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;
>   
>           led-controller@38 {
>                   compatible = "ti,lm3630a";

Looks good to me

Reviewed-by: Dan Murphy <redacted>
```

## Re: \[PATCH v3 2/2\] backlight: lm3630a: add an enable gpio for the HWEN pin

- From: Dan Murphy \<hidden\>
- Date: 2019-09-12 11:40:45 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5715515.md

```text
Andreas

On 9/11/19 12:21 PM, Andreas Kemnade wrote:
> For now just enable it in the probe function to allow i2c
> access. Disabling also means resetting the register values
> to default and according to the datasheet does not give
> power savings.
>
> Tested on Kobo Clara HD.
>
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> ---
> changes in v2:
> - simplification
> - correct gpio direction initialisation
>
> changes in v3:
> - removed legacy include
>
>   drivers/video/backlight/lm3630a_bl.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
>
> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> index 8f84f3684f04..d9e67b9b2571 100644
> --- a/drivers/video/backlight/lm3630a_bl.c
> +++ b/drivers/video/backlight/lm3630a_bl.c
> @@ -12,6 +12,7 @@
>   #include <linux/uaccess.h>
>   #include <linux/interrupt.h>
>   #include <linux/regmap.h>
> +#include <linux/gpio/consumer.h>
>   #include <linux/pwm.h>
>   #include <linux/platform_data/lm3630a_bl.h>
>   
> @@ -48,6 +49,7 @@ struct lm3630a_chip {
>   	struct lm3630a_platform_data *pdata;
>   	struct backlight_device *bleda;
>   	struct backlight_device *bledb;
> +	struct gpio_desc *enable_gpio;
>   	struct regmap *regmap;
>   	struct pwm_device *pwmd;
>   };
> @@ -535,6 +537,13 @@ static int lm3630a_probe(struct i2c_client *client,
>   	}
>   	pchip->pdata = pdata;
>   
> +	pchip->enable_gpio = devm_gpiod_get_optional(&client->dev, "enable",
> +						GPIOD_OUT_HIGH);
> +	if (IS_ERR(pchip->enable_gpio)) {
> +		rval = PTR_ERR(pchip->enable_gpio);
> +		return rval;
> +	}
> +
>   	/* chip initialize */
>   	rval = lm3630a_chip_init(pchip);
>   	if (rval < 0) {

Thanks for the explanation

It looks good to me

Reviewed-by: Dan Murphy <redacted>
```

## Re: \[PATCH v3 1/2\] dt-bindings: backlight: lm3630a: add enable\_gpios

- From: Andreas Kemnade \<andreas@kemnade.info\>
- Date: 2019-09-12 14:58:31 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5715686.md

```text
On Thu, 12 Sep 2019 06:39:50 -0500
Dan Murphy [ref] wrote:

> Andreas
> 
> On 9/11/19 12:21 PM, Andreas Kemnade wrote:
> > add enable-gpios to describe HWEN pin
> >
> > Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> > Acked-by: Daniel Thompson <redacted>
> > ---
> > changes in v2: added example
> > changes in v3: added Acked-by
> >   .../bindings/leds/backlight/lm3630a-backlight.yaml           | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
> > index dc129d9a329e..1fa83feffe16 100644
> > --- a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
> > +++ b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
> > @@ -29,6 +29,10 @@ properties:
> >     '#size-cells':
> >       const: 0
> >   
> > +  enable-gpios:
> > +    description: GPIO to use to enable/disable the backlight (HWEN pin).
> > +    maxItems: 1
> > +
> >   required:
> >     - compatible
> >     - reg
> > @@ -92,6 +96,7 @@ examples:
> >       i2c {
> >           #address-cells = <1>;
> >           #size-cells = <0>;
> > +        enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;
> >   
> >           led-controller@38 {
> >                   compatible = "ti,lm3630a";  
> 
> Looks good to me
> 
well, the enable-gpios is still at the same place as in v2. This was sent
before your comments to v2 have been arrived.

Regards,
Andreas
```

## Re: \[PATCH v3 1/2\] dt-bindings: backlight: lm3630a: add enable\_gpios

- From: Dan Murphy \<hidden\>
- Date: 2019-09-12 15:03:38 
- Message: https://ratatoskr.run/linux-fbdev/2019/09/5715692.md

```text
Andreas

On 9/12/19 9:58 AM, Andreas Kemnade wrote:
> On Thu, 12 Sep 2019 06:39:50 -0500
> Dan Murphy [ref] wrote:
>
>> Andreas
>>
>> On 9/11/19 12:21 PM, Andreas Kemnade wrote:
>>> add enable-gpios to describe HWEN pin
>>>
>>> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
>>> Acked-by: Daniel Thompson <redacted>
>>> ---
>>> changes in v2: added example
>>> changes in v3: added Acked-by
>>>    .../bindings/leds/backlight/lm3630a-backlight.yaml           | 5 +++++
>>>    1 file changed, 5 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
>>> index dc129d9a329e..1fa83feffe16 100644
>>> --- a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
>>> +++ b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
>>> @@ -29,6 +29,10 @@ properties:
>>>      '#size-cells':
>>>        const: 0
>>>    
>>> +  enable-gpios:
>>> +    description: GPIO to use to enable/disable the backlight (HWEN pin).
>>> +    maxItems: 1
>>> +
>>>    required:
>>>      - compatible
>>>      - reg
>>> @@ -92,6 +96,7 @@ examples:
>>>        i2c {
>>>            #address-cells = <1>;
>>>            #size-cells = <0>;
>>> +        enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;
>>>    
>>>            led-controller@38 {
>>>                    compatible = "ti,lm3630a";
>> Looks good to me
>>
> well, the enable-gpios is still at the same place as in v2. This was sent
> before your comments to v2 have been arrived.

Ah I overlooked that.  Yeah that still needs to move I assumed you moved it.

Dan


> Regards,
> Andreas
```