Re: [PATCH v15 06/11] drm/mediatek: Add MT8195 External DisplayPort support

[Rex-BC Chen <rex-bc.chen@mediatek.com>]

On Tue, 2022-08-02 at 10:37 +0800, CK Hu wrote:
> Hi, Bo-Chen:
> 
> On Wed, 2022-07-27 at 12:50 +0800, Bo-Chen Chen wrote:
> > 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>
> > Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dp.c     | 181 +++++++++++++++++++++-
> > --
> > --
> >  drivers/gpu/drm/mediatek/mtk_dp_reg.h |   1 +
> >  2 files changed, 146 insertions(+), 36 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c
> > b/drivers/gpu/drm/mediatek/mtk_dp.c
> > index 06eeecedd49e..ce817cb59445 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> > @@ -103,6 +103,11 @@ 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;
> 
> For external DP, it could also connect to a bridge IC which transfer
> DP
> to HDMI or some interface else. Use the compatible to judge this edp
> or
> dp.
> 

Hello CK,

ok, I will use of device data to do this.

> > +}
> > +
> >  static struct mtk_dp *mtk_dp_from_bridge(struct drm_bridge *b)
> >  {
> >  	return container_of(b, struct mtk_dp, bridge);
> > @@ -341,6 +346,19 @@ static void mtk_dp_pg_enable(struct mtk_dp
> > *mtk_dp, bool enable)
> >  			   4 << PGEN_PATTERN_SEL_SHIFT,
> > PGEN_PATTERN_SEL_MASK);
> >  }
> >  
> > +static bool mtk_dp_plug_state(struct mtk_dp *mtk_dp)
> > +{
> > +	return mtk_dp->train_info.cable_plugged_in;
> > +}
> > +
> > +static bool mtk_dp_plug_state_avoid_pulse(struct mtk_dp *mtk_dp)
> > +{
> > +	bool ret;
> > +
> > +	return !(readx_poll_timeout(mtk_dp_plug_state, mtk_dp, ret,
> > ret,
> > +				    4000, 7 * 4000));
> > +}
> > +
> >  static void mtk_dp_aux_irq_clear(struct mtk_dp *mtk_dp)
> >  {
> >  	mtk_dp_write(mtk_dp, MTK_DP_AUX_P0_3640,
> > @@ -778,35 +796,67 @@ static void
> > mtk_dp_get_calibration_data(struct
> > mtk_dp *mtk_dp)
> >  		return;
> >  	}
> >  
> > -	cal_data->glb_bias_trim =
> > -		check_cal_data_valid(mtk_dp, 1, 0x1e,
> > -				     (buf[3] >> 27) & 0x1f, 0xf);
> > -	cal_data->clktx_impse =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[0] >> 9) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_pmos[0] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[2] >> 28) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_nmos[0] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[2] >> 24) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_pmos[1] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[2] >> 20) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_nmos[1] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[2] >> 16) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_pmos[2] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[2] >> 12) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_nmos[2] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[2] >> 8) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_pmos[3] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe,
> > -				     (buf[2] >> 4) & 0xf, 0x8);
> > -	cal_data->ln_tx_impsel_nmos[3] =
> > -		check_cal_data_valid(mtk_dp, 1, 0xe, buf[2] & 0xf,
> > 0x8);
> > +	if (mtk_dp_is_edp(mtk_dp)) {
> > +		cal_data->glb_bias_trim =
> > +			check_cal_data_valid(mtk_dp, 1, 0x1e,
> > +					     (buf[3] >> 27) & 0x1f,
> > 0xf);
> > +		cal_data->clktx_impse =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[0] >> 9) & 0xf, 0x8);
> > +		cal_data->ln_tx_impsel_pmos[0] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[2] >> 28) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_nmos[0] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[2] >> 24) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_pmos[1] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[2] >> 20) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_nmos[1] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[2] >> 16) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_pmos[2] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[2] >> 12) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_nmos[2] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[2] >> 8) & 0xf, 0x8);
> > +		cal_data->ln_tx_impsel_pmos[3] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[2] >> 4) & 0xf, 0x8);
> > +		cal_data->ln_tx_impsel_nmos[3] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe, buf[2] &
> > 0xf, 0x8);
> > +	} else {
> > +		cal_data->glb_bias_trim =
> > +			check_cal_data_valid(mtk_dp, 1, 0x1e,
> > +					     (buf[0] >> 27) & 0x1f,
> > 0xf);
> 
> Why not place glb_bias_trim value in nvmem buf[3] for both edp and dp
> case? Place in the same nvmem position, the driver code would be
> simple. 
> 

These value are read from efuse data. do you mean change the order in
this dp driver?
Is so, I think it's not appropriate. It will be hard to debug if any
issue occurs.

> > +		cal_data->clktx_impse =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[0] >> 13) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_pmos[0] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[1] >> 28) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_nmos[0] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[1] >> 24) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_pmos[1] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[1] >> 20) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_nmos[1] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[1] >> 16) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_pmos[2] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[1] >> 12) & 0xf,
> > 0x8);
> > +		cal_data->ln_tx_impsel_nmos[2] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[1] >> 8) & 0xf, 0x8);
> > +		cal_data->ln_tx_impsel_pmos[3] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe,
> > +					     (buf[1] >> 4) & 0xf, 0x8);
> > +		cal_data->ln_tx_impsel_nmos[3] =
> > +			check_cal_data_valid(mtk_dp, 1, 0xe, buf[1] &
> > 0xf, 0x8);
> 
> Why not place ln_tx_impsel_nmos and ln_tx_impsel_pmos value in nvmem
> buf[2] for both edp and dp case? Place in the same nvmem position,
> the
> driver code would be simple. 
> 
> > +	}
> >  
> >  	kfree(buf);
> >  }
> > @@ -926,7 +976,10 @@ static void mtk_dp_video_mute(struct mtk_dp
> > *mtk_dp, bool enable)
> >  			   VIDEO_MUTE_SEL_DP_ENC0_P0_MASK |
> >  			   VIDEO_MUTE_SW_DP_ENC0_P0_MASK);
> >  
> > -	mtk_dp_sip_atf_call(mtk_dp, MTK_DP_SIP_ATF_EDP_VIDEO_UNMUTE,
> > enable);
> > +	mtk_dp_sip_atf_call(mtk_dp,
> > +			    mtk_dp_is_edp(mtk_dp) ?
> > +			    MTK_DP_SIP_ATF_EDP_VIDEO_UNMUTE :
> > +			    MTK_DP_SIP_ATF_VIDEO_UNMUTE, enable);
> 
> Use of_device_get_match_data to select
> MTK_DP_SIP_ATF_EDP_VIDEO_UNMUTE
> or MTK_DP_SIP_ATF_VIDEO_UNMUTE.
> 

Do you mean add a new variable to control this in of device match data?

BRs,
Bo-Chen

> >  }
> >  
> >  static void mtk_dp_power_enable(struct mtk_dp *mtk_dp)
> > @@ -1226,6 +1279,9 @@ static int mtk_dp_parse_capabilities(struct
> > mtk_dp *mtk_dp)
> >  	drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> > DP_SET_POWER_D0);
> >  	usleep_range(2000, 5000);
> >  
> > +	if (!mtk_dp_plug_state(mtk_dp))
> > +		return -ENODEV;
> > +
> >  	drm_dp_read_dpcd_caps(&mtk_dp->aux, mtk_dp->rx_cap);
> >  
> >  	train_info->link_rate = min_t(int, mtk_dp->max_linkrate,
> > @@ -1277,6 +1333,9 @@ static int mtk_dp_train_start(struct mtk_dp
> > *mtk_dp)
> >  	u8 train_limit;
> >  	u8 max_link_rate;
> >  
> > +	if (!mtk_dp_plug_state_avoid_pulse(mtk_dp))
> > +		return -ENODEV;
> > +
> >  	link_rate = mtk_dp->rx_cap[1];
> >  	lane_count = mtk_dp->rx_cap[2] & 0x1F;
> >  
> > @@ -1412,6 +1471,9 @@ static irqreturn_t
> > mtk_dp_hpd_event_thread(int
> > hpd, void *dev)
> >  {
> >  	struct mtk_dp *mtk_dp = dev;
> >  
> > +	dev_dbg(mtk_dp->dev, "drm_helper_hpd_irq_event\n");
> > +	drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
> 
> Because edp also have hpd interrupt, so I would like both edp and dp
> have the same control flow for hdp. So move this to edp patch.
> 
> > +
> >  	if (mtk_dp->train_info.hpd_inerrupt) {
> >  		dev_dbg(mtk_dp->dev, "MTK_DP_HPD_INTERRUPT\n");
> >  		mtk_dp->train_info.hpd_inerrupt = false;
> > @@ -1452,9 +1514,20 @@ static irqreturn_t mtk_dp_hpd_event(int hpd,
> > void *dev)
> >  		else
> >  			train_info->cable_plugged_in = false;
> >  
> > -		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> > -				   DP_PWR_STATE_BANDGAP_TPLL_LANE,
> > -				   DP_PWR_STATE_MASK);
> > +		if (!train_info->cable_plugged_in) {
> > +			mtk_dp_video_mute(mtk_dp, true);
> > +
> > +			mtk_dp_initialize_priv_data(mtk_dp);
> > +			mtk_dp_set_idle_pattern(mtk_dp, true);
> > +
> > +			mtk_dp_update_bits(mtk_dp,
> > MTK_DP_TOP_PWR_STATE,
> > +					   DP_PWR_STATE_BANDGAP_TPLL,
> > +					   DP_PWR_STATE_MASK);
> > +		} else {
> > +			mtk_dp_update_bits(mtk_dp,
> > MTK_DP_TOP_PWR_STATE,
> > +					   DP_PWR_STATE_BANDGAP_TPLL_LA
> > NE,
> > +					   DP_PWR_STATE_MASK);
> > +		}
> >  	}
> >  
> >  	return IRQ_HANDLED;
> > @@ -1499,6 +1572,24 @@ static int mtk_dp_dt_parse(struct mtk_dp
> > *mtk_dp,
> >  	return 0;
> >  }
> >  
> > +static enum drm_connector_status mtk_dp_bdg_detect(struct
> > drm_bridge
> > *bridge)
> > +{
> > +	struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
> > +	enum drm_connector_status ret = connector_status_disconnected;
> > +	u8 sink_count = 0;
> > +
> > +	if (mtk_dp_is_edp(mtk_dp))
> > +		return connector_status_connected;
> 
> Because edp also have hpd interrupt, so I would like both edp and dp
> have the same control flow for hdp. So remove this.
> 
> > +
> > +	if (mtk_dp_plug_state_avoid_pulse(mtk_dp)) {
> > +		drm_dp_dpcd_readb(&mtk_dp->aux, DP_SINK_COUNT,
> > &sink_count);
> > +		if (DP_GET_SINK_COUNT(sink_count))
> > +			ret = connector_status_connected;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> >  static struct edid *mtk_dp_get_edid(struct drm_bridge *bridge,
> >  				    struct drm_connector *connector)
> >  {
> > @@ -1512,7 +1603,8 @@ static struct edid *mtk_dp_get_edid(struct
> > drm_bridge *bridge,
> >  	drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> > DP_SET_POWER_D0);
> >  	usleep_range(2000, 5000);
> >  
> > -	new_edid = drm_get_edid(connector, &mtk_dp->aux.ddc);
> > +	if (mtk_dp_plug_state(mtk_dp))
> > +		new_edid = drm_get_edid(connector, &mtk_dp->aux.ddc);
> 
> Please explain why only dp has this problem. If edp also has this
> problem, move this to edp patch.
> 
> Regards,
> CK
> 
> >  
> >  	if (!enabled)
> >  		drm_bridge_chain_post_disable(bridge);
> > @@ -1852,6 +1944,7 @@ static const struct drm_bridge_funcs
> > mtk_dp_bridge_funcs = {
> >  	.atomic_disable = mtk_dp_bridge_atomic_disable,
> >  	.mode_valid = mtk_dp_bridge_mode_valid,
> >  	.get_edid = mtk_dp_get_edid,
> > +	.detect = mtk_dp_bdg_detect,
> >  };
> >  
> >  static int mtk_dp_probe(struct platform_device *pdev)
> > @@ -1873,9 +1966,15 @@ static int mtk_dp_probe(struct
> > platform_device
> > *pdev)
> >  				     "failed to request dp irq
> > resource\n");
> >  
> >  	mtk_dp->next_bridge = devm_drm_of_get_bridge(dev, dev-
> > >of_node, 
> > 1, 0);
> > -	if (IS_ERR(mtk_dp->next_bridge))
> > +	if (IS_ERR(mtk_dp->next_bridge) &&
> > +	    PTR_ERR(mtk_dp->next_bridge) == -ENODEV) {
> > +		dev_info(dev,
> > +			 "No panel connected in devicetree, continue as
> > external DP\n");
> > +		mtk_dp->next_bridge = NULL;
> > +	} else if (IS_ERR(mtk_dp->next_bridge)) {
> >  		return dev_err_probe(dev, PTR_ERR(mtk_dp->next_bridge),
> >  				     "Failed to get bridge\n");
> > +	}
> >  
> >  	ret = mtk_dp_dt_parse(mtk_dp, pdev);
> >  	if (ret)
> > @@ -1918,7 +2017,10 @@ static int mtk_dp_probe(struct
> > platform_device
> > *pdev)
> >  
> >  	mtk_dp->bridge.ops =
> >  		DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID |
> > DRM_BRIDGE_OP_HPD;
> > -	mtk_dp->bridge.type = DRM_MODE_CONNECTOR_eDP;
> > +	if (mtk_dp_is_edp(mtk_dp))
> > +		mtk_dp->bridge.type = DRM_MODE_CONNECTOR_eDP;
> > +	else
> > +		mtk_dp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
> >  
> >  	drm_bridge_add(&mtk_dp->bridge);
> >  
> > @@ -1945,6 +2047,12 @@ static int mtk_dp_suspend(struct device
> > *dev)
> >  {
> >  	struct mtk_dp *mtk_dp = dev_get_drvdata(dev);
> >  
> > +	if (mtk_dp_plug_state(mtk_dp)) {
> > +		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> > DP_SET_POWER_D3);
> > +		/* Ensure the sink is off before shutting down power */
> > +		usleep_range(2000, 3000);
> > +	}
> > +
> >  	mtk_dp_power_disable(mtk_dp);
> >  
> >  	mtk_dp_hwirq_enable(mtk_dp, false);
> > @@ -1978,6 +2086,7 @@ static SIMPLE_DEV_PM_OPS(mtk_dp_pm_ops,
> > mtk_dp_suspend, mtk_dp_resume);
> >  
> >  static const struct of_device_id mtk_dp_of_match[] = {
> >  	{ .compatible = "mediatek,mt8195-edp-tx" },
> > +	{ .compatible = "mediatek,mt8195-dp-tx" },
> >  	{},
> >  };
> >  MODULE_DEVICE_TABLE(of, mtk_dp_of_match);
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dp_reg.h
> > b/drivers/gpu/drm/mediatek/mtk_dp_reg.h
> > index 4ff8e9880dc9..59086eb82868 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dp_reg.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_dp_reg.h
> > @@ -14,6 +14,7 @@
> >  #define SEC_OFFSET	0x4000
> >  
> >  #define MTK_DP_SIP_ATF_EDP_VIDEO_UNMUTE	(BIT(0) | BIT(5))
> > +#define MTK_DP_SIP_ATF_VIDEO_UNMUTE	BIT(5)
> >  
> >  #define DP_PHY_GLB_BIAS_GEN_00		0
> >  #define RG_XTP_GLB_BIAS_INTR_CTRL	GENMASK(20, 16)
> 
>