* [PATCH v2 0/2] backlight_lm3630a: add enable_gpios property
@ 2019-09-10 21:29 Andreas Kemnade
2019-09-10 21:29 ` [PATCH v2 1/2] dt-bindings: backlight: lm3630a: add enable_gpios Andreas Kemnade
2019-09-10 21:29 ` [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin Andreas Kemnade
0 siblings, 2 replies; 9+ messages in thread
From: Andreas Kemnade @ 2019-09-10 21:29 UTC (permalink / raw)
To: lee.jones, daniel.thompson, jingoohan1, jacek.anaszewski, pavel,
dmurphy, robh+dt, mark.rutland, b.zolnierkie, dri-devel,
linux-leds, devicetree, linux-kernel, linux-fbdev,
H. Nikolaus Schaller
Cc: Andreas Kemnade
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
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 | 10 ++++++++++
2 files changed, 15 insertions(+)
--
2.20.1
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2 1/2] dt-bindings: backlight: lm3630a: add enable_gpios
2019-09-10 21:29 [PATCH v2 0/2] backlight_lm3630a: add enable_gpios property Andreas Kemnade
@ 2019-09-10 21:29 ` Andreas Kemnade
2019-09-11 10:08 ` Daniel Thompson
2019-09-10 21:29 ` [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin Andreas Kemnade
1 sibling, 1 reply; 9+ messages in thread
From: Andreas Kemnade @ 2019-09-10 21:29 UTC (permalink / raw)
To: lee.jones, daniel.thompson, jingoohan1, jacek.anaszewski, pavel,
dmurphy, robh+dt, mark.rutland, b.zolnierkie, dri-devel,
linux-leds, devicetree, linux-kernel, linux-fbdev,
H. Nikolaus Schaller
Cc: Andreas Kemnade
add enable-gpios to describe HWEN pin
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
changes in v2: add 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..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
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin
2019-09-10 21:29 [PATCH v2 0/2] backlight_lm3630a: add enable_gpios property Andreas Kemnade
2019-09-10 21:29 ` [PATCH v2 1/2] dt-bindings: backlight: lm3630a: add enable_gpios Andreas Kemnade
@ 2019-09-10 21:29 ` Andreas Kemnade
2019-09-11 10:25 ` Daniel Thompson
1 sibling, 1 reply; 9+ messages in thread
From: Andreas Kemnade @ 2019-09-10 21:29 UTC (permalink / raw)
To: lee.jones, daniel.thompson, jingoohan1, jacek.anaszewski, pavel,
dmurphy, robh+dt, mark.rutland, b.zolnierkie, dri-devel,
linux-leds, devicetree, linux-kernel, linux-fbdev,
H. Nikolaus Schaller
Cc: Andreas Kemnade
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
drivers/video/backlight/lm3630a_bl.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
index 8f84f3684f04..9d0639d4202d 100644
--- a/drivers/video/backlight/lm3630a_bl.c
+++ b/drivers/video/backlight/lm3630a_bl.c
@@ -12,6 +12,8 @@
#include <linux/uaccess.h>
#include <linux/interrupt.h>
#include <linux/regmap.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio.h>
#include <linux/pwm.h>
#include <linux/platform_data/lm3630a_bl.h>
@@ -48,6 +50,7 @@ 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 +538,13 @@ 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
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/2] dt-bindings: backlight: lm3630a: add enable_gpios
2019-09-10 21:29 ` [PATCH v2 1/2] dt-bindings: backlight: lm3630a: add enable_gpios Andreas Kemnade
@ 2019-09-11 10:08 ` Daniel Thompson
2019-09-11 18:44 ` Dan Murphy
0 siblings, 1 reply; 9+ messages in thread
From: Daniel Thompson @ 2019-09-11 10:08 UTC (permalink / raw)
To: Andreas Kemnade
Cc: lee.jones, jingoohan1, jacek.anaszewski, pavel, dmurphy, robh+dt,
mark.rutland, b.zolnierkie, dri-devel, linux-leds, devicetree,
linux-kernel, linux-fbdev, H. Nikolaus Schaller
On Tue, Sep 10, 2019 at 11:29:08PM +0200, Andreas Kemnade wrote:
> add enable-gpios to describe HWEN pin
>
> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
> changes in v2: add 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..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
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin
2019-09-10 21:29 ` [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin Andreas Kemnade
@ 2019-09-11 10:25 ` Daniel Thompson
2019-09-11 18:48 ` Dan Murphy
0 siblings, 1 reply; 9+ messages in thread
From: Daniel Thompson @ 2019-09-11 10:25 UTC (permalink / raw)
To: Andreas Kemnade
Cc: lee.jones, jingoohan1, jacek.anaszewski, pavel, dmurphy, robh+dt,
mark.rutland, b.zolnierkie, dri-devel, linux-leds, devicetree,
linux-kernel, linux-fbdev, H. Nikolaus Schaller
On Tue, Sep 10, 2019 at 11:29:09PM +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>
> ---
> changes in v2:
> - simplification
> - correct gpio direction initialisation
>
> drivers/video/backlight/lm3630a_bl.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> index 8f84f3684f04..9d0639d4202d 100644
> --- a/drivers/video/backlight/lm3630a_bl.c
> +++ b/drivers/video/backlight/lm3630a_bl.c
> @@ -12,6 +12,8 @@
> #include <linux/uaccess.h>
> #include <linux/interrupt.h>
> #include <linux/regmap.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/gpio.h>
Nitpicking... but I don't think linux/gpio.h is used anymore.
> #include <linux/pwm.h>
> #include <linux/platform_data/lm3630a_bl.h>
>
> @@ -48,6 +50,7 @@ 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 +538,13 @@ 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
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/2] dt-bindings: backlight: lm3630a: add enable_gpios
2019-09-11 10:08 ` Daniel Thompson
@ 2019-09-11 18:44 ` Dan Murphy
0 siblings, 0 replies; 9+ messages in thread
From: Dan Murphy @ 2019-09-11 18:44 UTC (permalink / raw)
To: Daniel Thompson, Andreas Kemnade
Cc: lee.jones, jingoohan1, jacek.anaszewski, pavel, robh+dt,
mark.rutland, b.zolnierkie, dri-devel, linux-leds, devicetree,
linux-kernel, linux-fbdev, H. Nikolaus Schaller
Andreas
On 9/11/19 5:08 AM, Daniel Thompson wrote:
> On Tue, Sep 10, 2019 at 11:29:08PM +0200, Andreas Kemnade wrote:
>> add enable-gpios to describe HWEN pin
>>
>> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
>
>> ---
>> changes in v2: add 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..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>;
This is in the wrong place. This is implying that the gpio is for the
i2c parent
This needs to go under the led-controller node below
Dan
>>
>> led-controller@38 {
>> compatible = "ti,lm3630a";
>> --
>> 2.20.1
>>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin
2019-09-11 10:25 ` Daniel Thompson
@ 2019-09-11 18:48 ` Dan Murphy
2019-09-11 20:25 ` Andreas Kemnade
2019-09-12 9:18 ` Daniel Thompson
0 siblings, 2 replies; 9+ messages in thread
From: Dan Murphy @ 2019-09-11 18:48 UTC (permalink / raw)
To: Daniel Thompson, Andreas Kemnade
Cc: lee.jones, jingoohan1, jacek.anaszewski, pavel, robh+dt,
mark.rutland, b.zolnierkie, dri-devel, linux-leds, devicetree,
linux-kernel, linux-fbdev, H. Nikolaus Schaller
On 9/11/19 5:25 AM, Daniel Thompson wrote:
> On Tue, Sep 10, 2019 at 11:29:09PM +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>
>> ---
>> changes in v2:
>> - simplification
>> - correct gpio direction initialisation
>>
>> drivers/video/backlight/lm3630a_bl.c | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
>> index 8f84f3684f04..9d0639d4202d 100644
>> --- a/drivers/video/backlight/lm3630a_bl.c
>> +++ b/drivers/video/backlight/lm3630a_bl.c
>> @@ -12,6 +12,8 @@
>> #include <linux/uaccess.h>
>> #include <linux/interrupt.h>
>> #include <linux/regmap.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/gpio.h>
> Nitpicking... but I don't think linux/gpio.h is used anymore.
>
>
>> #include <linux/pwm.h>
>> #include <linux/platform_data/lm3630a_bl.h>
>>
>> @@ -48,6 +50,7 @@ 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 +538,13 @@ 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;
the enable gpio is optional so if it fails you log the error and move on
Also on driver removal did you want to set the GPIO to low to disable
the device to save power?
Dan
>> + }
>> +
>> /* chip initialize */
>> rval = lm3630a_chip_init(pchip);
>> if (rval < 0) {
>> --
>> 2.20.1
>>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin
2019-09-11 18:48 ` Dan Murphy
@ 2019-09-11 20:25 ` Andreas Kemnade
2019-09-12 9:18 ` Daniel Thompson
1 sibling, 0 replies; 9+ messages in thread
From: Andreas Kemnade @ 2019-09-11 20:25 UTC (permalink / raw)
To: Dan Murphy
Cc: Daniel Thompson, lee.jones, jingoohan1, jacek.anaszewski, pavel,
robh+dt, mark.rutland, b.zolnierkie, dri-devel, linux-leds,
devicetree, linux-kernel, linux-fbdev, H. Nikolaus Schaller
On Wed, 11 Sep 2019 13:48:36 -0500
Dan Murphy <dmurphy@ti.com> wrote:
> >> @@ -535,6 +538,13 @@ 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;
>
> the enable gpio is optional so if it fails you log the error and move on
>
well, if the gpio is not there, then it returns NULL.
It might return e.g. -EDEFER. So I need to check for errors here.
> Also on driver removal did you want to set the GPIO to low to disable
> the device to save power?
>
page 5 of the datasheet says:
Ishdn = Typ. 1µA max. 4µA.
For HWEN=Vin, I2c shutdown (I guess this means outputs powered off)
ond for HWEN=GND.
So are we really saving something here?
Regards,
Andreas
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin
2019-09-11 18:48 ` Dan Murphy
2019-09-11 20:25 ` Andreas Kemnade
@ 2019-09-12 9:18 ` Daniel Thompson
1 sibling, 0 replies; 9+ messages in thread
From: Daniel Thompson @ 2019-09-12 9:18 UTC (permalink / raw)
To: Dan Murphy
Cc: Andreas Kemnade, lee.jones, jingoohan1, jacek.anaszewski, pavel,
robh+dt, mark.rutland, b.zolnierkie, dri-devel, linux-leds,
devicetree, linux-kernel, linux-fbdev, H. Nikolaus Schaller
On Wed, Sep 11, 2019 at 01:48:36PM -0500, Dan Murphy wrote:
>
> On 9/11/19 5:25 AM, Daniel Thompson wrote:
> > On Tue, Sep 10, 2019 at 11:29:09PM +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>
> > > ---
> > > changes in v2:
> > > - simplification
> > > - correct gpio direction initialisation
> > >
> > > drivers/video/backlight/lm3630a_bl.c | 10 ++++++++++
> > > 1 file changed, 10 insertions(+)
> > >
> > > diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
> > > index 8f84f3684f04..9d0639d4202d 100644
> > > --- a/drivers/video/backlight/lm3630a_bl.c
> > > +++ b/drivers/video/backlight/lm3630a_bl.c
> > > @@ -12,6 +12,8 @@
> > > #include <linux/uaccess.h>
> > > #include <linux/interrupt.h>
> > > #include <linux/regmap.h>
> > > +#include <linux/gpio/consumer.h>
> > > +#include <linux/gpio.h>
> > Nitpicking... but I don't think linux/gpio.h is used anymore.
> >
> >
> > > #include <linux/pwm.h>
> > > #include <linux/platform_data/lm3630a_bl.h>
> > > @@ -48,6 +50,7 @@ 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 +538,13 @@ 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;
>
> the enable gpio is optional so if it fails you log the error and move on
Isn't the effect of this to cope gracefully if enable-gpios is absent
but to fail with an error if enable-gpios exists and is broken. I
thought this code pattern is fairly common.
> Also on driver removal did you want to set the GPIO to low to disable the
> device to save power?
As it happens I offered to opposite feedback for v1:
https://lists.freedesktop.org/archives/dri-devel/2019-September/234918.html
Basically if the power matters then we should take care of things in the
PM code path (which for this driver means reacting properly to
suspended flag when updating the brightness). If the power doesn't matter
then, given unallocated GPIO pins are in an unknown state anyway, there
is no point in tidying up because we don't know what value to restore.
Daniel.
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2019-09-12 9:18 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
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2019-09-10 21:29 [PATCH v2 0/2] backlight_lm3630a: add enable_gpios property Andreas Kemnade
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2019-09-11 10:08 ` Daniel Thompson
2019-09-11 18:44 ` Dan Murphy
2019-09-10 21:29 ` [PATCH v2 2/2] backlight: lm3630a: add an enable gpio for the HWEN pin Andreas Kemnade
2019-09-11 10:25 ` Daniel Thompson
2019-09-11 18:48 ` Dan Murphy
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