diff mbox series

[v4,2/4] drm/panel-simple: Support for delays between GPIO & regulator

Message ID 1621927831-29471-3-git-send-email-rajeevny@codeaurora.org (mailing list archive)
State New, archived
Headers show
Series drm: Support basic DPCD backlight in panel-simple and add a new panel ATNA33XC20 | expand

Commit Message

Rajeev Nandan May 25, 2021, 7:30 a.m. UTC
Some panels datasheets may specify a delay between the enable GPIO and
the regulator. Support this in panel-simple.

Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
---

Changes in v4:
- New

 drivers/gpu/drm/panel/panel-simple.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

Comments

Doug Anderson May 25, 2021, 5:18 p.m. UTC | #1
Hi,

On Tue, May 25, 2021 at 12:31 AM Rajeev Nandan <rajeevny@codeaurora.org> wrote:
>
> Some panels datasheets may specify a delay between the enable GPIO and
> the regulator. Support this in panel-simple.
>
> Signed-off-by: Rajeev Nandan <rajeevny@codeaurora.org>
> ---
>
> Changes in v4:
> - New
>
>  drivers/gpu/drm/panel/panel-simple.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index f9e4e60..caed71b 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -134,6 +134,22 @@ struct panel_desc {
>                 unsigned int prepare_to_enable;
>
>                 /**
> +                * @delay.power_to_enable: Time for the power to enable the display on.
> +                *
> +                * The time (in milliseconds) that it takes for the panel to
> +                * turn the display on.

Maybe a slightly better description:

The time (in milliseconds) to wait after powering up the display
before asserting its enable pin.


> +                */
> +               unsigned int power_to_enable;
> +
> +               /**
> +                * @delay.disable_to_power_off: Time for the disable to power the display off.
> +                *
> +                * The time (in milliseconds) that it takes for the panel to
> +                * turn the display off.

Maybe a slightly better description:

The time (in milliseconds) to wait after disabling the display before
deasserting its enable pin.


> +                */
> +               unsigned int disable_to_power_off;
> +
> +               /**
>                  * @delay.enable: Time for the panel to display a valid frame.
>                  *
>                  * The time (in milliseconds) that it takes for the panel to
> @@ -367,6 +383,10 @@ static int panel_simple_suspend(struct device *dev)
>         struct panel_simple *p = dev_get_drvdata(dev);
>
>         gpiod_set_value_cansleep(p->enable_gpio, 0);
> +
> +       if (p->desc->delay.disable_to_power_off)
> +               msleep(p->desc->delay.disable_to_power_off);
> +

I wonder if it's worth a warning if
"p->desc->delay.disable_to_power_off" is non-zero and p->enable_gpio
is NULL? I guess in theory it'd also be nice to confirm that p->supply
wasn't a dummy regulator, but that's slightly harder.


>         regulator_disable(p->supply);
>         p->unprepared_time = ktime_get();
>
> @@ -427,6 +447,9 @@ static int panel_simple_prepare_once(struct panel_simple *p)
>                 return err;
>         }
>
> +       if (p->desc->delay.power_to_enable)
> +               msleep(p->desc->delay.power_to_enable);
> +

Similar to above: I wonder if it's worth a warning if
"p->desc->delay.power_to_enable" is non-zero and p->enable_gpio is
NULL?

-Doug
diff mbox series

Patch

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index f9e4e60..caed71b 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -134,6 +134,22 @@  struct panel_desc {
 		unsigned int prepare_to_enable;
 
 		/**
+		 * @delay.power_to_enable: Time for the power to enable the display on.
+		 *
+		 * The time (in milliseconds) that it takes for the panel to
+		 * turn the display on.
+		 */
+		unsigned int power_to_enable;
+
+		/**
+		 * @delay.disable_to_power_off: Time for the disable to power the display off.
+		 *
+		 * The time (in milliseconds) that it takes for the panel to
+		 * turn the display off.
+		 */
+		unsigned int disable_to_power_off;
+
+		/**
 		 * @delay.enable: Time for the panel to display a valid frame.
 		 *
 		 * The time (in milliseconds) that it takes for the panel to
@@ -367,6 +383,10 @@  static int panel_simple_suspend(struct device *dev)
 	struct panel_simple *p = dev_get_drvdata(dev);
 
 	gpiod_set_value_cansleep(p->enable_gpio, 0);
+
+	if (p->desc->delay.disable_to_power_off)
+		msleep(p->desc->delay.disable_to_power_off);
+
 	regulator_disable(p->supply);
 	p->unprepared_time = ktime_get();
 
@@ -427,6 +447,9 @@  static int panel_simple_prepare_once(struct panel_simple *p)
 		return err;
 	}
 
+	if (p->desc->delay.power_to_enable)
+		msleep(p->desc->delay.power_to_enable);
+
 	gpiod_set_value_cansleep(p->enable_gpio, 1);
 
 	delay = p->desc->delay.prepare;