Re: [PATCH v6 02/11] drm/mediatek: dp: Move AUX and panel poweron/off sequence to function

["CK Hu (胡俊光)" <ck.hu@mediatek.com>]

Hi, Angelo:

On Mon, 2023-07-17 at 16:14 +0200, AngeloGioacchino Del Regno wrote:
>  	 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>  Everytime we run bridge detection and/or EDID read we run a poweron
> and poweroff sequence for both the AUX and the panel; moreover, this
> is also done when enabling the bridge in the .atomic_enable()
> callback.
> 
> Move this power on/off sequence to a new mtk_dp_aux_panel_poweron()
> function as to commonize it.
> Note that, before this commit, in mtk_dp_bridge_atomic_enable() only
> the AUX was getting powered on but the panel was left powered off if
> the DP cable wasn't plugged in while now we unconditionally send a D0
> request and this is done for two reasons:
>  - First, whether this request fails or not, it takes the same time
>    and anyway the DP hardware won't produce any error (or, if it
>    does, it's ignorable because it won't block further commands)
>  - Second, training the link between a sleeping/standby/unpowered
>    display makes little sense.

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Tested-by: Chen-Yu Tsai <wenst@chromium.org>
> ---
>  drivers/gpu/drm/mediatek/mtk_dp.c | 76 ++++++++++++-----------------
> --
>  1 file changed, 30 insertions(+), 46 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c
> b/drivers/gpu/drm/mediatek/mtk_dp.c
> index c58b775877a3..77da0d002e9f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -1251,6 +1251,29 @@ static void mtk_dp_audio_mute(struct mtk_dp
> *mtk_dp, bool mute)
>  			   val[2], AU_TS_CFG_DP_ENC0_P0_MASK);
>  }
>  
> +static void mtk_dp_aux_panel_poweron(struct mtk_dp *mtk_dp, bool
> pwron)
> +{
> +	if (pwron) {
> +		/* power on aux */
> +		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> +				   DP_PWR_STATE_BANDGAP_TPLL_LANE,
> +				   DP_PWR_STATE_MASK);
> +
> +		/* power on panel */
> +		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D0);
> +		usleep_range(2000, 5000);
> +	} else {
> +		/* power off panel */
> +		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D3);
> +		usleep_range(2000, 3000);
> +
> +		/* power off aux */
> +		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> +				   DP_PWR_STATE_BANDGAP_TPLL,
> +				   DP_PWR_STATE_MASK);
> +	}
> +}
> +
>  static void mtk_dp_power_enable(struct mtk_dp *mtk_dp)
>  {
>  	mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_RESET_AND_PROBE,
> @@ -1941,16 +1964,9 @@ static enum drm_connector_status
> mtk_dp_bdg_detect(struct drm_bridge *bridge)
>  	if (!mtk_dp->train_info.cable_plugged_in)
>  		return ret;
>  
> -	if (!enabled) {
> -		/* power on aux */
> -		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> -				   DP_PWR_STATE_BANDGAP_TPLL_LANE,
> -				   DP_PWR_STATE_MASK);
> +	if (!enabled)
> +		mtk_dp_aux_panel_poweron(mtk_dp, true);
>  
> -		/* power on panel */
> -		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D0);
> -		usleep_range(2000, 5000);
> -	}
>  	/*
>  	 * Some dongles still source HPD when they do not connect to
> any
>  	 * sink device. To avoid this, we need to read the sink count
> @@ -1962,16 +1978,8 @@ static enum drm_connector_status
> mtk_dp_bdg_detect(struct drm_bridge *bridge)
>  	if (DP_GET_SINK_COUNT(sink_count))
>  		ret = connector_status_connected;
>  
> -	if (!enabled) {
> -		/* power off panel */
> -		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D3);
> -		usleep_range(2000, 3000);
> -
> -		/* power off aux */
> -		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> -				   DP_PWR_STATE_BANDGAP_TPLL,
> -				   DP_PWR_STATE_MASK);
> -	}
> +	if (!enabled)
> +		mtk_dp_aux_panel_poweron(mtk_dp, false);
>  
>  	return ret;
>  }
> @@ -1987,15 +1995,7 @@ static struct edid *mtk_dp_get_edid(struct
> drm_bridge *bridge,
>  
>  	if (!enabled) {
>  		drm_atomic_bridge_chain_pre_enable(bridge, connector-
> >state->state);
> -
> -		/* power on aux */
> -		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> -				   DP_PWR_STATE_BANDGAP_TPLL_LANE,
> -				   DP_PWR_STATE_MASK);
> -
> -		/* power on panel */
> -		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D0);
> -		usleep_range(2000, 5000);
> +		mtk_dp_aux_panel_poweron(mtk_dp, true);
>  	}
>  
>  	new_edid = drm_get_edid(connector, &mtk_dp->aux.ddc);
> @@ -2015,15 +2015,7 @@ static struct edid *mtk_dp_get_edid(struct
> drm_bridge *bridge,
>  	}
>  
>  	if (!enabled) {
> -		/* power off panel */
> -		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D3);
> -		usleep_range(2000, 3000);
> -
> -		/* power off aux */
> -		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> -				   DP_PWR_STATE_BANDGAP_TPLL,
> -				   DP_PWR_STATE_MASK);
> -
> +		mtk_dp_aux_panel_poweron(mtk_dp, false);
>  		drm_atomic_bridge_chain_post_disable(bridge, connector-
> >state->state);
>  	}
>  
> @@ -2183,15 +2175,7 @@ static void mtk_dp_bridge_atomic_enable(struct
> drm_bridge *bridge,
>  		return;
>  	}
>  
> -	/* power on aux */
> -	mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> -			   DP_PWR_STATE_BANDGAP_TPLL_LANE,
> -			   DP_PWR_STATE_MASK);
> -
> -	if (mtk_dp->train_info.cable_plugged_in) {
> -		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> DP_SET_POWER_D0);
> -		usleep_range(2000, 5000);
> -	}
> +	mtk_dp_aux_panel_poweron(mtk_dp, true);
>  
>  	/* Training */
>  	ret = mtk_dp_training(mtk_dp);
> -- 
> 2.40.1