[PATCH 31/36] drm/omap: Support for HDMI hot plug detection

[Tomi Valkeinen <tomi.valkeinen@xxxxxx>]

From: Peter Ujfalusi <peter.ujfalusi@xxxxxx>

The HPD signal can be used for detecting HDMI cable plug and unplug event
without the need for polling the status of the line.
This will speed up detecting such event because we do not need to wait for
the next poll event to notice the state change.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
---
 drivers/gpu/drm/omapdrm/dss/omapdss.h    | 13 +++++++++++++
 drivers/gpu/drm/omapdrm/omap_connector.c | 30 +++++++++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/omapdrm/dss/omapdss.h b/drivers/gpu/drm/omapdrm/dss/omapdss.h
index 8d04b02a7d35..a37170bcc3c4 100644
--- a/drivers/gpu/drm/omapdrm/dss/omapdss.h
+++ b/drivers/gpu/drm/omapdrm/dss/omapdss.h
@@ -25,6 +25,7 @@
 #include <video/videomode.h>
 #include <linux/platform_data/omapdss.h>
 #include <uapi/drm/drm_mode.h>
+#include <drm/drm_crtc.h>
 
 #define DISPC_IRQ_FRAMEDONE		(1 << 0)
 #define DISPC_IRQ_VSYNC			(1 << 1)
@@ -555,6 +556,12 @@ struct omapdss_hdmi_ops {
 	int (*read_edid)(struct omap_dss_device *dssdev, u8 *buf, int len);
 	bool (*detect)(struct omap_dss_device *dssdev);
 
+	int (*enable_hpd)(struct omap_dss_device *dssdev,
+			   void (*cb)(void *cb_data,
+				      enum drm_connector_status status),
+			   void *cb_data);
+	void (*disable_hpd)(struct omap_dss_device *dssdev);
+
 	int (*set_hdmi_mode)(struct omap_dss_device *dssdev, bool hdmi_mode);
 	int (*set_infoframe)(struct omap_dss_device *dssdev,
 		const struct hdmi_avi_infoframe *avi);
@@ -761,6 +768,12 @@ struct omap_dss_driver {
 	int (*read_edid)(struct omap_dss_device *dssdev, u8 *buf, int len);
 	bool (*detect)(struct omap_dss_device *dssdev);
 
+	int (*enable_hpd)(struct omap_dss_device *dssdev,
+			   void (*cb)(void *cb_data,
+				      enum drm_connector_status status),
+			   void *cb_data);
+	void (*disable_hpd)(struct omap_dss_device *dssdev);
+
 	int (*set_hdmi_mode)(struct omap_dss_device *dssdev, bool hdmi_mode);
 	int (*set_hdmi_infoframe)(struct omap_dss_device *dssdev,
 		const struct hdmi_avi_infoframe *avi);
diff --git a/drivers/gpu/drm/omapdrm/omap_connector.c b/drivers/gpu/drm/omapdrm/omap_connector.c
index da53df4811ac..60b438431355 100644
--- a/drivers/gpu/drm/omapdrm/omap_connector.c
+++ b/drivers/gpu/drm/omapdrm/omap_connector.c
@@ -35,6 +35,17 @@ struct omap_connector {
 	bool hdmi_mode;
 };
 
+void omap_connector_hpd_cb(void *cb_data, enum drm_connector_status status)
+{
+	struct omap_connector *omap_connector = cb_data;
+	struct drm_connector *connector = &omap_connector->base;
+
+	if (connector->status != status) {
+		connector->status = status;
+		drm_kms_helper_hotplug_event(omap_connector->base.dev);
+	}
+}
+
 bool omap_connector_get_hdmi_mode(struct drm_connector *connector)
 {
 	struct omap_connector *omap_connector = to_omap_connector(connector);
@@ -75,6 +86,9 @@ static void omap_connector_destroy(struct drm_connector *connector)
 	struct omap_dss_device *dssdev = omap_connector->dssdev;
 
 	DBG("%s", omap_connector->dssdev->name);
+	if (connector->polled == DRM_CONNECTOR_POLL_HPD &&
+	    dssdev->driver->disable_hpd)
+		dssdev->driver->disable_hpd(dssdev);
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
 	kfree(omap_connector);
@@ -212,6 +226,7 @@ struct drm_connector *omap_connector_init(struct drm_device *dev,
 {
 	struct drm_connector *connector = NULL;
 	struct omap_connector *omap_connector;
+	bool hpd_supported = false;
 
 	DBG("%s", dssdev->name);
 
@@ -229,7 +244,20 @@ struct drm_connector *omap_connector_init(struct drm_device *dev,
 				connector_type);
 	drm_connector_helper_add(connector, &omap_connector_helper_funcs);
 
-	if (dssdev->driver->detect)
+	if (dssdev->driver->enable_hpd) {
+		int ret = dssdev->driver->enable_hpd(dssdev,
+						     omap_connector_hpd_cb,
+						     omap_connector);
+		if (!ret)
+			hpd_supported = true;
+		else if (ret != -ENOTSUPP)
+			DBG("%s: enable_hpd failed (%d). HPD will be disabled",
+			    dssdev->name, ret);
+	}
+
+	if (hpd_supported)
+		connector->polled = DRM_CONNECTOR_POLL_HPD;
+	else if (dssdev->driver->detect)
 		connector->polled = DRM_CONNECTOR_POLL_CONNECT |
 				    DRM_CONNECTOR_POLL_DISCONNECT;
 	else
-- 
2.7.4

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