[v4,1/5] pwm-backlight: enable/disable the PWM before/after LCD enable toggle.

Message ID 20170721104813.5389-1-enric.balletbo@collabora.com
State New
Headers show

Commit Message

Enric Balletbo i Serra July 21, 2017, 10:48 a.m.
Before this patch the enable signal was set before the PWM signal and
vice-versa on power off. This sequence is wrong, at least, it is on
the different panels datasheets that I checked, so I inverted the sequence
to follow the specs.

For reference the following panels have the mentioned sequence:
  - N133HSE-EA1 (Innolux)
  - N116BGE (Innolux)
  - N156BGE-L21 (Innolux)
  - B101EAN0 (Auo)
  - B101AW03 (Auo)
  - LTN101NT05 (Samsung)
  - CLAA101WA01A (Chunghwa)

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
---
Changes since v3:
 - List the part numbers for the panel checked (Daniel Thompson)
Changes since v2:
 - Add this as a separate patch (Thierry Reding)
Changes since v1:
 - None

 drivers/video/backlight/pwm_bl.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Daniel Thompson July 24, 2017, 3:13 p.m. | #1
On 21/07/17 11:48, Enric Balletbo i Serra wrote:
> Before this patch the enable signal was set before the PWM signal and
> vice-versa on power off. This sequence is wrong, at least, it is on
> the different panels datasheets that I checked, so I inverted the sequence
> to follow the specs.
> 
> For reference the following panels have the mentioned sequence:
>    - N133HSE-EA1 (Innolux)
>    - N116BGE (Innolux)
>    - N156BGE-L21 (Innolux)
>    - B101EAN0 (Auo)
>    - B101AW03 (Auo)
>    - LTN101NT05 (Samsung)
>    - CLAA101WA01A (Chunghwa)
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Acked-by: Daniel Thompson <daniel.thompson@linaro.org>

> ---
> Changes since v3:
>   - List the part numbers for the panel checked (Daniel Thompson)
> Changes since v2:
>   - Add this as a separate patch (Thierry Reding)
> Changes since v1:
>   - None
> 
>   drivers/video/backlight/pwm_bl.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 002f1ce..909a686 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -54,10 +54,11 @@ static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
>   	if (err < 0)
>   		dev_err(pb->dev, "failed to enable power supply\n");
>   
> +	pwm_enable(pb->pwm);
> +
>   	if (pb->enable_gpio)
>   		gpiod_set_value_cansleep(pb->enable_gpio, 1);
>   
> -	pwm_enable(pb->pwm);
>   	pb->enabled = true;
>   }
>   
> @@ -66,12 +67,12 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)
>   	if (!pb->enabled)
>   		return;
>   
> -	pwm_config(pb->pwm, 0, pb->period);
> -	pwm_disable(pb->pwm);
> -
>   	if (pb->enable_gpio)
>   		gpiod_set_value_cansleep(pb->enable_gpio, 0);
>   
> +	pwm_config(pb->pwm, 0, pb->period);
> +	pwm_disable(pb->pwm);
> +
>   	regulator_disable(pb->power_supply);
>   	pb->enabled = false;
>   }
> 

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Jingoo Han July 25, 2017, 5:49 p.m. | #2
On Monday, July 24, 2017 11:14 AM, Daniel Thompson wrote:
> On 21/07/17 11:48, Enric Balletbo i Serra wrote:
> > Before this patch the enable signal was set before the PWM signal and
> > vice-versa on power off. This sequence is wrong, at least, it is on
> > the different panels datasheets that I checked, so I inverted the
> sequence
> > to follow the specs.
> >
> > For reference the following panels have the mentioned sequence:
> >    - N133HSE-EA1 (Innolux)
> >    - N116BGE (Innolux)
> >    - N156BGE-L21 (Innolux)
> >    - B101EAN0 (Auo)
> >    - B101AW03 (Auo)
> >    - LTN101NT05 (Samsung)
> >    - CLAA101WA01A (Chunghwa)
> >
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> 
> Acked-by: Daniel Thompson <daniel.thompson@linaro.org>

Acked-by: Jingoo Han <jingoohan1@gmail.com>

Best regards,
Jingoo Han

> 
> > ---
> > Changes since v3:
> >   - List the part numbers for the panel checked (Daniel Thompson)
> > Changes since v2:
> >   - Add this as a separate patch (Thierry Reding)
> > Changes since v1:
> >   - None
> >
> >   drivers/video/backlight/pwm_bl.c | 9 +++++----
> >   1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/video/backlight/pwm_bl.c
> b/drivers/video/backlight/pwm_bl.c
> > index 002f1ce..909a686 100644
> > --- a/drivers/video/backlight/pwm_bl.c
> > +++ b/drivers/video/backlight/pwm_bl.c
> > @@ -54,10 +54,11 @@ static void pwm_backlight_power_on(struct
> pwm_bl_data *pb, int brightness)
> >   	if (err < 0)
> >   		dev_err(pb->dev, "failed to enable power supply\n");
> >
> > +	pwm_enable(pb->pwm);
> > +
> >   	if (pb->enable_gpio)
> >   		gpiod_set_value_cansleep(pb->enable_gpio, 1);
> >
> > -	pwm_enable(pb->pwm);
> >   	pb->enabled = true;
> >   }
> >
> > @@ -66,12 +67,12 @@ static void pwm_backlight_power_off(struct
> pwm_bl_data *pb)
> >   	if (!pb->enabled)
> >   		return;
> >
> > -	pwm_config(pb->pwm, 0, pb->period);
> > -	pwm_disable(pb->pwm);
> > -
> >   	if (pb->enable_gpio)
> >   		gpiod_set_value_cansleep(pb->enable_gpio, 0);
> >
> > +	pwm_config(pb->pwm, 0, pb->period);
> > +	pwm_disable(pb->pwm);
> > +
> >   	regulator_disable(pb->power_supply);
> >   	pb->enabled = false;
> >   }
> >


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Patch

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 002f1ce..909a686 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -54,10 +54,11 @@  static void pwm_backlight_power_on(struct pwm_bl_data *pb, int brightness)
 	if (err < 0)
 		dev_err(pb->dev, "failed to enable power supply\n");
 
+	pwm_enable(pb->pwm);
+
 	if (pb->enable_gpio)
 		gpiod_set_value_cansleep(pb->enable_gpio, 1);
 
-	pwm_enable(pb->pwm);
 	pb->enabled = true;
 }
 
@@ -66,12 +67,12 @@  static void pwm_backlight_power_off(struct pwm_bl_data *pb)
 	if (!pb->enabled)
 		return;
 
-	pwm_config(pb->pwm, 0, pb->period);
-	pwm_disable(pb->pwm);
-
 	if (pb->enable_gpio)
 		gpiod_set_value_cansleep(pb->enable_gpio, 0);
 
+	pwm_config(pb->pwm, 0, pb->period);
+	pwm_disable(pb->pwm);
+
 	regulator_disable(pb->power_supply);
 	pb->enabled = false;
 }