drm/vc4: hdmi: Restore cec physical address on reconnect

Currently we call cec_phys_addr_invalidate on a hotplug deassert.
That may be due to a TV power cycling, or an AVR being switched
on (and switching edid).

This makes CEC unusable since our controller wouldn't have a physical
address anymore.

Set it back up again on the hotplug assert.

Fixes: 15b4511a ("drm/vc4: add HDMI CEC support")
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Tested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111142309.193441-6-maxime@cerno.tech
(cherry picked from commit b06eecb5)
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -136,20 +136,32 @@ static enum drm_connector_status
 vc4_hdmi_connector_detect(struct drm_connector *connector, bool force)
 {
 	struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);
+	bool connected = false;
 
 	if (vc4_hdmi->hpd_gpio) {
 		if (gpio_get_value_cansleep(vc4_hdmi->hpd_gpio) ^
 		    vc4_hdmi->hpd_active_low)
-			return connector_status_connected;
-		cec_phys_addr_invalidate(vc4_hdmi->cec_adap);
-		return connector_status_disconnected;
+			connected = true;
+	} else if (drm_probe_ddc(vc4_hdmi->ddc)) {
+		connected = true;
+	} else if (HDMI_READ(HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED) {
+		connected = true;
 	}
 
-	if (drm_probe_ddc(vc4_hdmi->ddc))
-		return connector_status_connected;
+	if (connected) {
+		if (connector->status != connector_status_connected) {
+			struct edid *edid = drm_get_edid(connector, vc4_hdmi->ddc);
+
+			if (edid) {
+				cec_s_phys_addr_from_edid(vc4_hdmi->cec_adap, edid);
+				vc4_hdmi->encoder.hdmi_monitor = drm_detect_hdmi_monitor(edid);
+				kfree(edid);
+			}
+		}
 
-	if (HDMI_READ(HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED)
 		return connector_status_connected;
+	}
+
 	cec_phys_addr_invalidate(vc4_hdmi->cec_adap);
 	return connector_status_disconnected;
 }