backlight_lm3630a: add enable_gpios property

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

Changes in v4:
added reviewed-by
moved gpio to the right position in the bindings example

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

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
changes in v4: moved enable-gpios to the right position
  in the example
 .../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..c8470628fe02 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

@@ -96,6 +100,7 @@ examples:
         led-controller@38 {
                 compatible = "ti,lm3630a";
                 reg = <0x38>;
+                enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;
 
                 #address-cells = <1>;
                 #size-cells = <0>;

-- 
2.20.1

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>
Reviewed-by: Dan Murphy <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
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

Andreas

On 9/12/19 4:32 PM, Andreas Kemnade wrote:

add enable-gpios to describe HWEN pin

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Daniel Thompson <redacted>

Reviewed-by: Dan Murphy <redacted>

On Thu, 12 Sep 2019 23:32:56 +0200, 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
changes in v4: moved enable-gpios to the right position
  in the example
 .../bindings/leds/backlight/lm3630a-backlight.yaml           | 5 +++++
 1 file changed, 5 insertions(+)

Reviewed-by: Rob Herring <robh@kernel.org>

On Thu, 12 Sep 2019, Andreas Kemnade wrote:

Provide DT documentation for enable-gpios.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Daniel Thompson <redacted>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Dan Murphy <redacted>
---
changes in v2: added example
changes in v3: added Acked-by
changes in v4: moved enable-gpios to the right position
  in the example
 .../bindings/leds/backlight/lm3630a-backlight.yaml           | 5 +++++
 1 file changed, 5 insertions(+)

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

On Thu, 12 Sep 2019, 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>
Reviewed-by: Dan Murphy <redacted>
Reviewed-by: Daniel Thompson <redacted>
---
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(+)

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

On Thu, Sep 12, 2019 at 4:33 PM Andreas Kemnade [off-list ref] wrote:

add enable-gpios to describe HWEN pin

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Daniel Thompson <redacted>

This breaking linux-next now...

Error: Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.example.dts:24.46-47
syntax error
FATAL ERROR: Unable to parse input tree
make[1]: *** [Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.example.dt.yaml]
Error 1
scripts/Makefile.lib:314: recipe for target
'Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.example.dt.yaml'
failed

You need the include for the define.

Rob

Hi,

On Mon, 28 Oct 2019 18:25:56 -0500
Rob Herring [off-list ref] wrote:

On Thu, Sep 12, 2019 at 4:33 PM Andreas Kemnade [off-list ref] wrote:

quoted

add enable-gpios to describe HWEN pin

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Daniel Thompson <redacted>  

This breaking linux-next now...

oops, sorry. 

quoted

---
changes in v2: added example
changes in v3: added Acked-by
changes in v4: moved enable-gpios to the right position
  in the example
 .../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..c8470628fe02 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

@@ -96,6 +100,7 @@ examples:
         led-controller@38 {
                 compatible = "ti,lm3630a";
                 reg = <0x38>;
+                enable-gpios = <&gpio2 5 GPIO_ACTIVE_HIGH>;  

Error: Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.example.dts:24.46-47
syntax error
FATAL ERROR: Unable to parse input tree
make[1]: *** [Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.example.dt.yaml]
Error 1
scripts/Makefile.lib:314: recipe for target
'Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.example.dt.yaml'
failed

You need the include for the define.

gpio/gpio.h is missing.
Yes, was not aware of that these things will be compiled and the automatic
check did not work on my system at all. So I decided not to fix that for just
this simple thing which was a not so good idea.
Will send a fixup.

Regards,
Andreas