Re: [PATCH v12 06/10] drm/mediatek: Add MT8195 External DisplayPort support

[AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>]

Il 27/06/22 10:03, Bo-Chen Chen ha scritto:
> From: Guillaume Ranquet <granquet@baylibre.com>
> 
> This patch adds External DisplayPort support to the mt8195 eDP driver.
> 
> Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
> [Bo-Chen: Move some dp features here and modify for reviewers' comments.]
> Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
> ---
>   drivers/gpu/drm/mediatek/mtk_dp.c | 217 ++++++++++++++++++++++++------
>   1 file changed, 174 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index 9e9b516409e2..1697c61462b7 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -111,6 +111,7 @@ struct mtk_dp {
>   	struct regmap *regs;
>   
>   	bool enabled;
> +	bool has_fec;
>   
>   	struct drm_connector *conn;
>   };
> @@ -123,6 +124,11 @@ static struct regmap_config mtk_dp_regmap_config = {
>   	.name = "mtk-dp-registers",
>   };
>   
> +static bool mtk_dp_is_edp(struct mtk_dp *mtk_dp)
> +{
> +	return mtk_dp->next_bridge;
> +}
> +
>   static struct mtk_dp *mtk_dp_from_bridge(struct drm_bridge *b)
>   {
>   	return container_of(b, struct mtk_dp, bridge);
> @@ -401,6 +407,20 @@ static bool mtk_dp_plug_state(struct mtk_dp *mtk_dp)
>   		  HPD_DB_DP_TRANS_P0_MASK);
>   }
>   
> +static bool mtk_dp_plug_state_avoid_pulse(struct mtk_dp *mtk_dp)
> +{
> +	int wait;
> +
> +	for (wait = 7; !mtk_dp_plug_state(mtk_dp) && wait > 0; --wait)
> +		/* Avoid short pulses on the HPD isr */
> +		usleep_range(1000, 5000);
> +
> +	if (wait == 0)
> +		return false;
> +

You can as well use existing APIs for that:

static bool mtk_dp_plug_state_avoid_pulse(struct mtk_dp *mtk_dp)
{
	int ret;

	return !!(readx_poll_timeout(mtk_dp_plug_state, mtk_dp, ret, ret,
				     4000, (7 * 4000)));
}

P.S.: I've used 4000 instead of 5000 on purpose, check the definition of
       readx_poll_timeout for more information.

All the rest of this commit looks good to me.

Cheers,
Angelo