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From:   Guillaume Ranquet <granquet@baylibre.com>
To:     airlied@linux.ie, angelogioacchino.delregno@collabora.com,
        chunfeng.yun@mediatek.com, chunkuang.hu@kernel.org,
        ck.hu@mediatek.com, daniel@ffwll.ch, deller@gmx.de,
        jitao.shi@mediatek.com, kishon@ti.com, krzk+dt@kernel.org,
        maarten.lankhorst@linux.intel.com, matthias.bgg@gmail.com,
        mripard@kernel.org, p.zabel@pengutronix.de, robh+dt@kernel.org,
        tzimmermann@suse.de, vkoul@kernel.org
Cc:     devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-fbdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org,
        linux-phy@lists.infradead.org, markyacoub@google.com
Subject: [PATCH v9 19/22] drm/mediatek: Add mt8195 External DisplayPort support
Date:   Mon, 28 Mar 2022 00:39:24 +0200
Message-Id: <20220327223927.20848-20-granquet@baylibre.com>
In-Reply-To: <20220327223927.20848-1-granquet@baylibre.com>
References: <20220327223927.20848-1-granquet@baylibre.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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This patch adds External DisplayPort support to the mt8195 eDP driver.

Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
---
 drivers/gpu/drm/mediatek/mtk_dp.c | 301 +++++++++++++++++++++++++++---
 1 file changed, 278 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
index 7cd8459cf719..9e532408f12e 100644
--- a/drivers/gpu/drm/mediatek/mtk_dp.c
+++ b/drivers/gpu/drm/mediatek/mtk_dp.c
@@ -176,6 +176,11 @@ struct mtk_dp {
 	struct drm_connector *conn;
 };
 
+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);
@@ -741,6 +746,47 @@ static int mtk_dp_fec_enable(struct mtk_dp *mtk_dp, bool enable)
 			   FEC_EN_DP_TRANS_P0_MASK);
 }
 
+static u32 mtk_dp_swirq_get_clear(struct mtk_dp *mtk_dp)
+{
+	int ret;
+
+	u32 irq_status = mtk_dp_read(mtk_dp, MTK_DP_TRANS_P0_35D0) &
+			 SW_IRQ_FINAL_STATUS_DP_TRANS_P0_MASK;
+
+	if (irq_status) {
+		MTK_UPD_BITS_OR_OUT(mtk_dp, MTK_DP_TRANS_P0_35C8, irq_status,
+				    SW_IRQ_CLR_DP_TRANS_P0_MASK, ret, out);
+		MTK_UPD_BITS_OR_OUT(mtk_dp, MTK_DP_TRANS_P0_35C8, 0,
+				    SW_IRQ_CLR_DP_TRANS_P0_MASK, ret, out);
+	}
+
+	return irq_status;
+
+out:
+	return ret;
+}
+
+static u32 mtk_dp_hwirq_get_clear(struct mtk_dp *mtk_dp)
+{
+	int ret;
+
+	u8 irq_status = (mtk_dp_read(mtk_dp, MTK_DP_TRANS_P0_3418) &
+			 IRQ_STATUS_DP_TRANS_P0_MASK) >>
+			IRQ_STATUS_DP_TRANS_P0_SHIFT;
+
+	if (irq_status) {
+		MTK_UPD_BITS_OR_OUT(mtk_dp, MTK_DP_TRANS_P0_3418, irq_status,
+				    IRQ_CLR_DP_TRANS_P0_MASK, ret, out);
+		MTK_UPD_BITS_OR_OUT(mtk_dp, MTK_DP_TRANS_P0_3418, 0,
+				    IRQ_CLR_DP_TRANS_P0_MASK, ret, out);
+	}
+
+	return irq_status;
+
+out:
+	return ret;
+}
+
 static int mtk_dp_hwirq_enable(struct mtk_dp *mtk_dp, bool enable)
 {
 	u32 val = 0;
@@ -932,26 +978,49 @@ static int mtk_dp_get_calibration_data(struct mtk_dp *mtk_dp)
 		return PTR_ERR(buf);
 	}
 
-	cal_data->glb_bias_trim =
-		check_cal_data_valid(1, 0x1e, (buf[3] >> 27) & 0x1f, 0xf);
-	cal_data->clktx_impse =
-		check_cal_data_valid(1, 0xe, (buf[0] >> 9) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_pmos[0] =
-		check_cal_data_valid(1, 0xe, (buf[2] >> 28) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_nmos[0] =
-		check_cal_data_valid(1, 0xe, (buf[2] >> 24) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_pmos[1] =
-		check_cal_data_valid(1, 0xe, (buf[2] >> 20) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_nmos[1] =
-		check_cal_data_valid(1, 0xe, (buf[2] >> 16) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_pmos[2] =
-		check_cal_data_valid(1, 0xe, (buf[2] >> 12) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_nmos[2] =
-		check_cal_data_valid(1, 0xe, (buf[2] >> 8) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_pmos[3] =
-		check_cal_data_valid(1, 0xe, (buf[2] >> 4) & 0xf, 0x8);
-	cal_data->ln_tx_impsel_nmos[3] =
-		check_cal_data_valid(1, 0xe, buf[2] & 0xf, 0x8);
+	if (mtk_dp_is_edp(mtk_dp)) {
+		cal_data->glb_bias_trim =
+			check_cal_data_valid(1, 0x1e, (buf[3] >> 27) & 0x1f, 0xf);
+		cal_data->clktx_impse =
+			check_cal_data_valid(1, 0xe, (buf[0] >> 9) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[0] =
+			check_cal_data_valid(1, 0xe, (buf[2] >> 28) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[0] =
+			check_cal_data_valid(1, 0xe, (buf[2] >> 24) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[1] =
+			check_cal_data_valid(1, 0xe, (buf[2] >> 20) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[1] =
+			check_cal_data_valid(1, 0xe, (buf[2] >> 16) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[2] =
+			check_cal_data_valid(1, 0xe, (buf[2] >> 12) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[2] =
+			check_cal_data_valid(1, 0xe, (buf[2] >> 8) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[3] =
+			check_cal_data_valid(1, 0xe, (buf[2] >> 4) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[3] =
+			check_cal_data_valid(1, 0xe, buf[2] & 0xf, 0x8);
+	} else {
+		cal_data->glb_bias_trim =
+			check_cal_data_valid(1, 0x1e, (buf[0] >> 27) & 0x1f, 0xf);
+		cal_data->clktx_impse =
+			check_cal_data_valid(1, 0xe, (buf[0] >> 13) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[0] =
+			check_cal_data_valid(1, 0xe, (buf[1] >> 28) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[0] =
+			check_cal_data_valid(1, 0xe, (buf[1] >> 24) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[1] =
+			check_cal_data_valid(1, 0xe, (buf[1] >> 20) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[1] =
+			check_cal_data_valid(1, 0xe, (buf[1] >> 16) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[2] =
+			check_cal_data_valid(1, 0xe, (buf[1] >> 12) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[2] =
+			check_cal_data_valid(1, 0xe, (buf[1] >> 8) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_pmos[3] =
+			check_cal_data_valid(1, 0xe, (buf[1] >> 4) & 0xf, 0x8);
+		cal_data->ln_tx_impsel_nmos[3] =
+			check_cal_data_valid(1, 0xe, buf[1] & 0xf, 0x8);
+	}
 
 	kfree(buf);
 
@@ -1080,7 +1149,10 @@ 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_SIP_ATF_EDP_VIDEO_UNMUTE, enable);
+	if (mtk_dp_is_edp(mtk_dp))
+		mtk_dp_sip_atf_call(MTK_DP_SIP_ATF_EDP_VIDEO_UNMUTE, enable);
+	else
+		mtk_dp_sip_atf_call(MTK_DP_SIP_ATF_VIDEO_UNMUTE, enable);
 }
 
 static int mtk_dp_power_enable(struct mtk_dp *mtk_dp)
@@ -1195,6 +1267,57 @@ static void mtk_dp_set_tx_out(struct mtk_dp *mtk_dp)
 	mtk_dp_setup_tu(mtk_dp);
 }
 
+static void mtk_dp_edid_free(struct mtk_dp *mtk_dp)
+{
+	mutex_lock(&mtk_dp->edid_lock);
+	kfree(mtk_dp->edid);
+	mtk_dp->edid = NULL;
+	mutex_unlock(&mtk_dp->edid_lock);
+}
+
+static int mtk_dp_hpd_sink_event(struct mtk_dp *mtk_dp)
+{
+	ssize_t ret;
+	u8 sink_count;
+	bool locked;
+	u8 link_status[DP_LINK_STATUS_SIZE] = {};
+	u32 sink_count_reg = DP_SINK_COUNT_ESI;
+	u32 link_status_reg = DP_LANE0_1_STATUS;
+
+	ret = drm_dp_dpcd_readb(&mtk_dp->aux, sink_count_reg, &sink_count);
+	if (ret < 0) {
+		drm_err(mtk_dp->drm_dev, "Read sink count failed: %ld\n", ret);
+		return ret;
+	}
+
+	ret = drm_dp_dpcd_read(&mtk_dp->aux, link_status_reg, link_status,
+			       sizeof(link_status));
+	if (!ret) {
+		drm_err(mtk_dp->drm_dev, "Read link status failed: %ld\n",
+			ret);
+		return ret;
+	}
+
+	locked = drm_dp_channel_eq_ok(link_status,
+				      mtk_dp->train_info.lane_count);
+	if (!locked && mtk_dp->train_state > MTK_DP_TRAIN_STATE_TRAINING_PRE)
+		mtk_dp->train_state = MTK_DP_TRAIN_STATE_TRAINING_PRE;
+
+	if (link_status[1] & DP_REMOTE_CONTROL_COMMAND_PENDING)
+		drm_dp_dpcd_writeb(&mtk_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR,
+				   DP_REMOTE_CONTROL_COMMAND_PENDING);
+
+	if (DP_GET_SINK_COUNT(sink_count) &&
+	    (link_status[2] & DP_DOWNSTREAM_PORT_STATUS_CHANGED)) {
+		mtk_dp_edid_free(mtk_dp);
+		mtk_dp->train_info.check_cap_count = 0;
+		mtk_dp->train_state = MTK_DP_TRAIN_STATE_CHECKEDID;
+		msleep(20);
+	}
+
+	return 0;
+}
+
 static void mtk_dp_train_update_swing_pre(struct mtk_dp *mtk_dp, int lanes,
 					  u8 dpcd_adjust_req[2])
 {
@@ -1677,6 +1800,115 @@ static void mtk_dp_init_port(struct mtk_dp *mtk_dp)
 	mtk_dp_digital_sw_reset(mtk_dp);
 }
 
+static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
+{
+	struct mtk_dp *mtk_dp = dev;
+	int event;
+	u8 buf[DP_RECEIVER_CAP_SIZE] = {};
+
+	event = mtk_dp_plug_state(mtk_dp) ? connector_status_connected :
+						  connector_status_disconnected;
+
+	if (event < 0)
+		return IRQ_HANDLED;
+
+	if (mtk_dp->drm_dev) {
+		dev_info(mtk_dp->dev, "drm_helper_hpd_irq_event\n");
+		drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
+	}
+
+	if (mtk_dp->train_info.cable_state_change) {
+		mtk_dp->train_info.cable_state_change = false;
+
+		mtk_dp->train_state = MTK_DP_TRAIN_STATE_STARTUP;
+
+		if (!mtk_dp->train_info.cable_plugged_in ||
+		    !mtk_dp_plug_state(mtk_dp)) {
+			mtk_dp_video_mute(mtk_dp, true);
+
+			mtk_dp_initialize_priv_data(mtk_dp);
+			mtk_dp_set_idle_pattern(mtk_dp, true);
+			if (mtk_dp->has_fec)
+				mtk_dp_fec_enable(mtk_dp, false);
+
+			mtk_dp_edid_free(mtk_dp);
+			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_LANE,
+					   DP_PWR_STATE_MASK);
+			drm_dp_read_dpcd_caps(&mtk_dp->aux, buf);
+			mtk_dp->train_info.link_rate =
+				min_t(int, MTK_DP_MAX_LINK_RATE,
+				      buf[DP_MAX_LINK_RATE]);
+			mtk_dp->train_info.lane_count =
+				min_t(int, MTK_DP_MAX_LANES,
+				      drm_dp_max_lane_count(buf));
+		}
+	}
+
+	if (mtk_dp->train_info.irq_status & MTK_DP_HPD_INTERRUPT) {
+		dev_dbg(mtk_dp->dev, "MTK_DP_HPD_INTERRUPT\n");
+		mtk_dp->train_info.irq_status &= ~MTK_DP_HPD_INTERRUPT;
+		mtk_dp_hpd_sink_event(mtk_dp);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mtk_dp_hpd_isr_handler(struct mtk_dp *mtk_dp)
+{
+	bool connected;
+	u16 swirq_status = mtk_dp_swirq_get_clear(mtk_dp);
+	u8 hwirq_status = mtk_dp_hwirq_get_clear(mtk_dp);
+	struct mtk_dp_train_info *train_info = &mtk_dp->train_info;
+
+	train_info->irq_status |= hwirq_status | swirq_status;
+
+	if (!train_info->irq_status)
+		return IRQ_HANDLED;
+
+	connected = mtk_dp_plug_state(mtk_dp);
+	if (connected || !train_info->cable_plugged_in)
+		train_info->irq_status &= ~MTK_DP_HPD_DISCONNECT;
+	else if (!connected || train_info->cable_plugged_in)
+		train_info->irq_status &= ~MTK_DP_HPD_CONNECT;
+
+	if (!(train_info->irq_status &
+	      (MTK_DP_HPD_CONNECT | MTK_DP_HPD_DISCONNECT)))
+		return IRQ_HANDLED;
+
+	if (train_info->irq_status & MTK_DP_HPD_CONNECT) {
+		train_info->irq_status &= ~MTK_DP_HPD_CONNECT;
+		train_info->cable_plugged_in = true;
+	} else {
+		train_info->irq_status &= ~MTK_DP_HPD_DISCONNECT;
+		train_info->cable_plugged_in = false;
+		mtk_dp->train_state = MTK_DP_TRAIN_STATE_STARTUP;
+	}
+	train_info->cable_state_change = true;
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t mtk_dp_hpd_event(int hpd, void *dev)
+{
+	struct mtk_dp *mtk_dp = dev;
+	u32 irq_status;
+
+	irq_status = mtk_dp_read(mtk_dp, MTK_DP_TOP_IRQ_STATUS);
+
+	if (!irq_status)
+		return IRQ_HANDLED;
+
+	if (irq_status & RGS_IRQ_STATUS_TRANSMITTER)
+		return mtk_dp_hpd_isr_handler(mtk_dp);
+
+	return IRQ_HANDLED;
+}
+
 static int mtk_dp_dt_parse(struct mtk_dp *mtk_dp,
 			   struct platform_device *pdev)
 {
@@ -2110,6 +2342,7 @@ static int mtk_dp_probe(struct platform_device *pdev)
 	struct mtk_dp *mtk_dp;
 	struct device *dev = &pdev->dev;
 	int ret;
+	int irq_num = 0;
 
 	mtk_dp = devm_kzalloc(dev, sizeof(*mtk_dp), GFP_KERNEL);
 	if (!mtk_dp)
@@ -2117,9 +2350,18 @@ static int mtk_dp_probe(struct platform_device *pdev)
 
 	mtk_dp->dev = dev;
 
+	irq_num = platform_get_irq(pdev, 0);
+	if (irq_num < 0)
+		return dev_err_probe(dev, irq_num, "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, continuing 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)
@@ -2129,6 +2371,13 @@ static int mtk_dp_probe(struct platform_device *pdev)
 	mtk_dp->aux.name = "aux_mtk_dp";
 	mtk_dp->aux.transfer = mtk_dp_aux_transfer;
 
+	ret = devm_request_threaded_irq(dev, irq_num, mtk_dp_hpd_event,
+					mtk_dp_hpd_event_thread,
+					IRQ_TYPE_LEVEL_HIGH, dev_name(dev),
+					mtk_dp);
+	if (ret)
+		return dev_err_probe(dev, -EPROBE_DEFER, "failed to request mediatek dptx irq\n");
+
 	mutex_init(&mtk_dp->dp_lock);
 	mutex_init(&mtk_dp->edid_lock);
 
@@ -2145,8 +2394,13 @@ static int mtk_dp_probe(struct platform_device *pdev)
 	mtk_dp->bridge.of_node = dev->of_node;
 	mtk_dp->bridge.type = DRM_MODE_CONNECTOR_eDP;
 
-	mtk_dp->bridge.ops = DRM_BRIDGE_OP_EDID;
+	mtk_dp->bridge.ops =
+		DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_HPD;
 	drm_bridge_add(&mtk_dp->bridge);
+	if (mtk_dp_is_edp(mtk_dp))
+		mtk_dp->bridge.type = DRM_MODE_CONNECTOR_eDP;
+	else
+		mtk_dp->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
 
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
@@ -2201,6 +2455,7 @@ 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);
-- 
2.34.1