Hi,
On Tue, May 25, 2021 at 12:31 AM Rajeev Nandan <rajeevny@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> ---
>
> 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
