diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index f3fcdbf662fa..a90ab5c0f5cf 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -279,6 +279,7 @@ struct zynqmp_dp_config {
  * @dpsub: Display subsystem
  * @iomem: device I/O memory for register access
  * @reset: reset controller
+ * @lock: Mutex protecting this struct and register access (but not AUX)
  * @irq: irq
  * @bridge: DRM bridge for the DP encoder
  * @next_bridge: The downstream bridge
@@ -294,12 +295,17 @@ struct zynqmp_dp_config {
  * @link_config: common link configuration between IP core and sink device
  * @mode: current mode between IP core and sink device
  * @train_set: set of training data
+ *
+ * @lock covers the link configuration in this struct and the device's
+ * registers. It does not cover @aux. It is not strictly required for any of
+ * the members which are only modified at probe/remove time (e.g. @dev).
  */
 struct zynqmp_dp {
 	struct drm_dp_aux aux;
 	struct drm_bridge bridge;
 	struct delayed_work hpd_work;
 	struct delayed_work hpd_irq_work;
+	struct mutex lock;
 
 	struct drm_bridge *next_bridge;
 	struct device *dev;
@@ -1373,8 +1379,10 @@ zynqmp_dp_bridge_mode_valid(struct drm_bridge *bridge,
 	}
 
 	/* Check with link rate and lane count */
+	mutex_lock(&dp->lock);
 	rate = zynqmp_dp_max_rate(dp->link_config.max_rate,
 				  dp->link_config.max_lanes, dp->config.bpp);
+	mutex_unlock(&dp->lock);
 	if (mode->clock > rate) {
 		dev_dbg(dp->dev, "filtered mode %s for high pixel rate\n",
 			mode->name);
@@ -1401,6 +1409,7 @@ static void zynqmp_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 
 	pm_runtime_get_sync(dp->dev);
 
+	mutex_lock(&dp->lock);
 	zynqmp_dp_disp_enable(dp, old_bridge_state);
 
 	/*
@@ -1461,6 +1470,7 @@ static void zynqmp_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 	zynqmp_dp_write(dp, ZYNQMP_DP_SOFTWARE_RESET,
 			ZYNQMP_DP_SOFTWARE_RESET_ALL);
 	zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_ENABLE, 1);
+	mutex_unlock(&dp->lock);
 }
 
 static void zynqmp_dp_bridge_atomic_disable(struct drm_bridge *bridge,
@@ -1468,6 +1478,7 @@ static void zynqmp_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 {
 	struct zynqmp_dp *dp = bridge_to_dp(bridge);
 
+	mutex_lock(&dp->lock);
 	dp->enabled = false;
 	cancel_delayed_work(&dp->hpd_work);
 	zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_ENABLE, 0);
@@ -1478,6 +1489,7 @@ static void zynqmp_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 		zynqmp_dp_write(dp, ZYNQMP_DP_TX_AUDIO_CONTROL, 0);
 
 	zynqmp_dp_disp_disable(dp, old_bridge_state);
+	mutex_unlock(&dp->lock);
 
 	pm_runtime_put_sync(dp->dev);
 }
@@ -1520,6 +1532,8 @@ static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *brid
 	u32 state, i;
 	int ret;
 
+	mutex_lock(&dp->lock);
+
 	/*
 	 * This is from heuristic. It takes some delay (ex, 100 ~ 500 msec) to
 	 * get the HPD signal with some monitors.
@@ -1547,11 +1561,13 @@ static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *brid
 					       dp->num_lanes);
 
 		dp->status = connector_status_connected;
+		mutex_unlock(&dp->lock);
 		return connector_status_connected;
 	}
 
 disconnected:
 	dp->status = connector_status_disconnected;
+	mutex_unlock(&dp->lock);
 	return connector_status_disconnected;
 }
 
@@ -1620,6 +1636,7 @@ static void zynqmp_dp_hpd_irq_work_func(struct work_struct *work)
 	u8 status[DP_LINK_STATUS_SIZE + 2];
 	int err;
 
+	mutex_lock(&dp->lock);
 	err = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
 			       DP_LINK_STATUS_SIZE + 2);
 	if (err < 0) {
@@ -1632,6 +1649,7 @@ static void zynqmp_dp_hpd_irq_work_func(struct work_struct *work)
 			zynqmp_dp_train_loop(dp);
 		}
 	}
+	mutex_unlock(&dp->lock);
 }
 
 static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
@@ -1683,6 +1701,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub)
 	dp->dev = &pdev->dev;
 	dp->dpsub = dpsub;
 	dp->status = connector_status_disconnected;
+	mutex_init(&dp->lock);
 
 	INIT_DELAYED_WORK(&dp->hpd_work, zynqmp_dp_hpd_work_func);
 	INIT_DELAYED_WORK(&dp->hpd_irq_work, zynqmp_dp_hpd_irq_work_func);
@@ -1793,4 +1812,5 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub)
 
 	zynqmp_dp_phy_exit(dp);
 	zynqmp_dp_reset(dp, true);
+	mutex_destroy(&dp->lock);
 }
