[RFC/RFT PATCH 2/4] drm/bridge: dw-hdmi: Add support for custom PHY handling

[Neil Armstrong]

The Synopsys DesignWare HDMI TX Controller support various Transceivers (PHY)
attached to the controller, but also allows fully custom PHYs to be connected.

Add PHY init, disable functions in plat_data to handle fully custom PHY init.

Some custom PHYs also handles the HPD and RxSense separately and do not use
the internal signals exported in the Controller's IRQ stat, so a read_hpd
is provided to switch to HPD status polling.
To complete the implementation, add a function to mimic the Controllers
interrupt HPD and RxSense handling from the vendor PHY wrapper code.

Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
 drivers/gpu/drm/bridge/dw-hdmi.c | 78 +++++++++++++++++++++++++++++++---------
 include/drm/bridge/dw_hdmi.h     |  8 +++++
 2 files changed, 70 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
index 13747fe..923e250 100644
--- a/drivers/gpu/drm/bridge/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/dw-hdmi.c
@@ -1434,9 +1434,18 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
 	hdmi_av_composer(hdmi, mode);
 
 	/* HDMI Initializateion Step B.2 */
-	ret = dw_hdmi_phy_init(hdmi);
-	if (ret)
-		return ret;
+	if (hdmi->plat_data->hdmi_phy_init) {
+		ret = hdmi->plat_data->hdmi_phy_init(hdmi, hdmi->plat_data,
+						     &hdmi->previous_mode);
+		if (ret)
+			return ret;
+
+		hdmi->phy_enabled = true;
+	} else {
+		ret = dw_hdmi_phy_init(hdmi);
+		if (ret)
+			return ret;
+	}
 
 	/* HDMI Initialization Step B.3 */
 	dw_hdmi_enable_video_path(hdmi);
@@ -1551,7 +1560,11 @@ static void dw_hdmi_poweron(struct dw_hdmi *hdmi)
 
 static void dw_hdmi_poweroff(struct dw_hdmi *hdmi)
 {
-	dw_hdmi_phy_disable(hdmi);
+	if (hdmi->phy_enabled && hdmi->plat_data->hdmi_phy_disable) {
+		hdmi->plat_data->hdmi_phy_disable(hdmi, hdmi->plat_data);
+		hdmi->phy_enabled = false;
+	} else
+		dw_hdmi_phy_disable(hdmi);
 	hdmi->bridge_is_on = false;
 }
 
@@ -1593,6 +1606,9 @@ static void dw_hdmi_update_phy_mask(struct dw_hdmi *hdmi)
 {
 	u8 old_mask = hdmi->phy_mask;
 
+	if (hdmi->plat_data && hdmi->plat_data->hdmi_read_hpd)
+		return;
+
 	if (hdmi->force || hdmi->disabled || !hdmi->rxsense)
 		hdmi->phy_mask |= HDMI_PHY_RX_SENSE;
 	else
@@ -1614,6 +1630,11 @@ static void dw_hdmi_update_phy_mask(struct dw_hdmi *hdmi)
 	dw_hdmi_update_phy_mask(hdmi);
 	mutex_unlock(&hdmi->mutex);
 
+	if (hdmi->plat_data && hdmi->plat_data->hdmi_read_hpd)
+		return hdmi->plat_data->hdmi_read_hpd(hdmi, hdmi->plat_data) ?
+			connector_status_connected :
+			connector_status_disconnected;
+
 	return hdmi_readb(hdmi, HDMI_PHY_STAT0) & HDMI_PHY_HPD ?
 		connector_status_connected : connector_status_disconnected;
 }
@@ -1901,6 +1922,26 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
 	}
 };
 
+void dw_hdmi_setup_rx_sense(struct device *dev, bool hpd, bool rx_sense)
+{
+	struct dw_hdmi *hdmi = dev_get_drvdata(dev);
+
+	mutex_lock(&hdmi->mutex);
+
+	if (!hdmi->disabled && !hdmi->force) {
+		if (!rx_sense)
+			hdmi->rxsense = false;
+
+		if (hpd)
+			hdmi->rxsense = true;
+
+		dw_hdmi_update_power(hdmi);
+		dw_hdmi_update_phy_mask(hdmi);
+	}
+	mutex_unlock(&hdmi->mutex);
+}
+EXPORT_SYMBOL_GPL(dw_hdmi_setup_rx_sense);
+
 static int dw_hdmi_detect_phy(struct dw_hdmi *hdmi)
 {
 	unsigned int i;
@@ -1921,7 +1962,9 @@ static int dw_hdmi_detect_phy(struct dw_hdmi *hdmi)
 		return -ENODEV;
 	}
 
-	if (!hdmi->phy->configure && !hdmi->plat_data->configure_phy) {
+	if (!hdmi->phy->configure &&
+	    !hdmi->plat_data->configure_phy &&
+	    !hdmi->plat_data->hdmi_phy_init) {
 		dev_err(hdmi->dev, "%s requires platform support\n",
 			hdmi->phy->name);
 		return -ENODEV;
@@ -2101,15 +2144,17 @@ static int dw_hdmi_detect_phy(struct dw_hdmi *hdmi)
 			hdmi->ddc = NULL;
 	}
 
-	/*
-	 * Configure registers related to HDMI interrupt
-	 * generation before registering IRQ.
-	 */
-	hdmi_writeb(hdmi, HDMI_PHY_HPD | HDMI_PHY_RX_SENSE, HDMI_PHY_POL0);
+	if (!hdmi->plat_data || !hdmi->plat_data->hdmi_read_hpd) {
+		/*
+		 * Configure registers related to HDMI interrupt
+		 * generation before registering IRQ.
+		 */
+		hdmi_writeb(hdmi, HDMI_PHY_HPD | HDMI_PHY_RX_SENSE, HDMI_PHY_POL0);
 
-	/* Clear Hotplug interrupts */
-	hdmi_writeb(hdmi, HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE,
-		    HDMI_IH_PHY_STAT0);
+		/* Clear Hotplug interrupts */
+		hdmi_writeb(hdmi, HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE,
+			    HDMI_IH_PHY_STAT0);
+	}
 
 	hdmi->bridge.driver_private = hdmi;
 	hdmi->bridge.funcs = &dw_hdmi_bridge_funcs;
@@ -2119,9 +2164,10 @@ static int dw_hdmi_detect_phy(struct dw_hdmi *hdmi)
 	if (ret)
 		goto err_iahb;
 
-	/* Unmute interrupts */
-	hdmi_writeb(hdmi, ~(HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE),
-		    HDMI_IH_MUTE_PHY_STAT0);
+	if (!hdmi->plat_data || !hdmi->plat_data->hdmi_read_hpd)
+		/* Unmute interrupts */
+		hdmi_writeb(hdmi, ~(HDMI_IH_PHY_STAT0_HPD | HDMI_IH_PHY_STAT0_RX_SENSE),
+			    HDMI_IH_MUTE_PHY_STAT0);
 
 	memset(&pdevinfo, 0, sizeof(pdevinfo));
 	pdevinfo.parent = dev;
diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
index 163842d..d6a0ab3 100644
--- a/include/drm/bridge/dw_hdmi.h
+++ b/include/drm/bridge/dw_hdmi.h
@@ -61,6 +61,13 @@ struct dw_hdmi_plat_data {
 	enum drm_mode_status (*mode_valid)(struct drm_connector *connector,
 					   struct drm_display_mode *mode);
 	struct regmap *regm;
+	int (*hdmi_phy_init)(struct dw_hdmi *hdmi,
+			     const struct dw_hdmi_plat_data *data,
+			     struct drm_display_mode *mode);
+	void (*hdmi_phy_disable)(struct dw_hdmi *hdmi,
+				 const struct dw_hdmi_plat_data *data);
+	bool (*hdmi_read_hpd)(struct dw_hdmi *hdmi,
+			      const struct dw_hdmi_plat_data *data);
 };
 
 int dw_hdmi_probe(struct platform_device *pdev,
@@ -70,6 +77,7 @@ int dw_hdmi_probe(struct platform_device *pdev,
 int dw_hdmi_bind(struct platform_device *pdev, struct drm_encoder *encoder,
 		 const struct dw_hdmi_plat_data *plat_data);
 
+void dw_hdmi_setup_rx_sense(struct device *dev, bool hpd, bool rx_sense);
 void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate);
 void dw_hdmi_audio_enable(struct dw_hdmi *hdmi);
 void dw_hdmi_audio_disable(struct dw_hdmi *hdmi);
-- 
1.9.1