[PATCH 1/3] drm/omap: Support for HDMI hot plug detection

[Peter Ujfalusi]

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>
---
 drivers/gpu/drm/omapdrm/dss/omapdss.h    | 17 +++++++++++++++++
 drivers/gpu/drm/omapdrm/omap_connector.c | 32 +++++++++++++++++++++++++++++++-
 drivers/gpu/drm/omapdrm/omap_drv.c       | 29 +++++++++++++++++++++++++++++
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/omapdrm/dss/omapdss.h b/drivers/gpu/drm/omapdrm/dss/omapdss.h
index b19dae1fd6c5..1f01669eb610 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 +556,14 @@ struct omapdss_hdmi_ops {
 	int (*read_edid)(struct omap_dss_device *dssdev, u8 *buf, int len);
 	bool (*detect)(struct omap_dss_device *dssdev);
 
+	int (*register_hpd_cb)(struct omap_dss_device *dssdev,
+			       void (*cb)(void *cb_data,
+					  enum drm_connector_status status),
+			       void *cb_data);
+	void (*unregister_hpd_cb)(struct omap_dss_device *dssdev);
+	void (*enable_hpd)(struct omap_dss_device *dssdev);
+	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 +770,14 @@ struct omap_dss_driver {
 	int (*read_edid)(struct omap_dss_device *dssdev, u8 *buf, int len);
 	bool (*detect)(struct omap_dss_device *dssdev);
 
+	int (*register_hpd_cb)(struct omap_dss_device *dssdev,
+			       void (*cb)(void *cb_data,
+					  enum drm_connector_status status),
+			       void *cb_data);
+	void (*unregister_hpd_cb)(struct omap_dss_device *dssdev);
+	void (*enable_hpd)(struct omap_dss_device *dssdev);
+	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 c24b6b783e9a..5219e340ed9d 100644
--- a/drivers/gpu/drm/omapdrm/omap_connector.c
+++ b/drivers/gpu/drm/omapdrm/omap_connector.c
@@ -35,6 +35,18 @@ struct omap_connector {
 	bool hdmi_mode;
 };
 
+static 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 +87,10 @@ 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->unregister_hpd_cb) {
+		dssdev->driver->unregister_hpd_cb(dssdev);
+	}
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
 	kfree(omap_connector);
@@ -216,6 +232,7 @@ 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);
 
@@ -233,7 +250,20 @@ 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->register_hpd_cb) {
+		int ret = dssdev->driver->register_hpd_cb(dssdev,
+							  omap_connector_hpd_cb,
+							  omap_connector);
+		if (!ret)
+			hpd_supported = true;
+		else if (ret != -ENOTSUPP)
+			DBG("%s: Failed to register HPD callback (%d).",
+			    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
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index e1f47f0b3ccf..6e54e4d446a9 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -394,6 +394,32 @@ static int omap_modeset_init(struct drm_device *dev)
 }
 
 /*
+ * Enable the HPD in external components if supported
+ */
+static void omap_modeset_enable_external_hpd(void)
+{
+	struct omap_dss_device *dssdev = NULL;
+
+	for_each_dss_dev(dssdev) {
+		if (dssdev->driver->enable_hpd)
+			dssdev->driver->enable_hpd(dssdev);
+	}
+}
+
+/*
+ * Disable the HPD in external components if supported
+ */
+static void omap_modeset_disable_external_hpd(void)
+{
+	struct omap_dss_device *dssdev = NULL;
+
+	for_each_dss_dev(dssdev) {
+		if (dssdev->driver->disable_hpd)
+			dssdev->driver->disable_hpd(dssdev);
+	}
+}
+
+/*
  * drm ioctl funcs
  */
 
@@ -710,6 +736,7 @@ static int pdev_probe(struct platform_device *pdev)
 	priv->fbdev = omap_fbdev_init(ddev);
 
 	drm_kms_helper_poll_init(ddev);
+	omap_modeset_enable_external_hpd();
 
 	/*
 	 * Register the DRM device with the core and the connectors with
@@ -722,6 +749,7 @@ static int pdev_probe(struct platform_device *pdev)
 	return 0;
 
 err_cleanup_helpers:
+	omap_modeset_disable_external_hpd();
 	drm_kms_helper_poll_fini(ddev);
 	if (priv->fbdev)
 		omap_fbdev_free(ddev);
@@ -750,6 +778,7 @@ static int pdev_remove(struct platform_device *pdev)
 
 	drm_dev_unregister(ddev);
 
+	omap_modeset_disable_external_hpd();
 	drm_kms_helper_poll_fini(ddev);
 
 	if (priv->fbdev)
-- 
2.12.2