drm/dp_mst: Fix the DDC I2C device registration of an MST port

From Imre Deak
cb22808ac2759706a410d89e1219de611a3b2fe4 in linux 5.7.y/5.7.17
d8bd15b37d328a935a4fc695fed8b19157503950 in mainline linux

1 files changed, 16 insertions, 12 deletions

diff --git a/sys/dev/pci/drm/drm_dp_mst_topology.c b/sys/dev/pci/drm/drm_dp_mst_topology.c
index 7e04b77c303..29d76d44cc8 100644
--- a/sys/dev/pci/drm/drm_dp_mst_topology.c
+++ b/sys/dev/pci/drm/drm_dp_mst_topology.c
@@ -88,8 +88,8 @@ static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
 static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
 				 u8 *guid);
 
-static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
-static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
+static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
+static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
 
 #define DBG_PREFIX "[dp_mst]"
@@ -1981,7 +1981,7 @@ drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
 			}
 
 			/* remove i2c over sideband */
-			drm_dp_mst_unregister_i2c_bus(&port->aux);
+			drm_dp_mst_unregister_i2c_bus(port);
 		} else {
 			mutex_lock(&mgr->lock);
 			drm_dp_mst_topology_put_mstb(port->mstb);
@@ -1996,7 +1996,7 @@ drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
 	if (port->pdt != DP_PEER_DEVICE_NONE) {
 		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
 			/* add i2c over sideband */
-			ret = drm_dp_mst_register_i2c_bus(&port->aux);
+			ret = drm_dp_mst_register_i2c_bus(port);
 		} else {
 			lct = drm_dp_calculate_rad(port, rad);
 			mstb = drm_dp_add_mst_branch_device(lct, rad);
@@ -5416,12 +5416,15 @@ static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
 
 /**
  * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
- * @aux: DisplayPort AUX channel
+ * @port: The port to add the I2C bus on
  *
  * Returns 0 on success or a negative error code on failure.
  */
-static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
+static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
 {
+	struct drm_dp_aux *aux = &port->aux;
+	struct device *parent_dev = port->mgr->dev->dev;
+
 	aux->ddc.algo = &drm_dp_mst_i2c_algo;
 	aux->ddc.algo_data = aux;
 	aux->ddc.retries = 3;
@@ -5429,11 +5432,12 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
 #ifdef __linux__
 	aux->ddc.class = I2C_CLASS_DDC;
 	aux->ddc.owner = THIS_MODULE;
-	aux->ddc.dev.parent = aux->dev;
-	aux->ddc.dev.of_node = aux->dev->of_node;
+	/* FIXME: set the kdev of the port's connector as parent */
+	aux->ddc.dev.parent = parent_dev;
+	aux->ddc.dev.of_node = parent_dev->of_node;
 #endif
 
-	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
+	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
 		sizeof(aux->ddc.name));
 
 	return i2c_add_adapter(&aux->ddc);
@@ -5441,11 +5445,11 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
 
 /**
  * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
- * @aux: DisplayPort AUX channel
+ * @port: The port to remove the I2C bus from
  */
-static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
+static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
 {
-	i2c_del_adapter(&aux->ddc);
+	i2c_del_adapter(&port->aux.ddc);
 }
 
 /**