From: Prashant Malani <pmalani@xxxxxxxxxxxx> When using OF graph, the fw_devlink code will create links between the individual port driver (cros-ec-typec here) and the parent device for a Type-C switch (like mode-switch). Since the mode-switch will in turn have the usb-c-connector (i.e the child of the port driver) as a supplier, fw_devlink will not be able to resolve the cyclic dependency correctly. As a result, the mode-switch driver probe() never runs, so mode-switches are never registered. Because of that, the port driver probe constantly fails with -EPROBE_DEFER, because the Type-C connector class requires all switch devices to be registered prior to port registration. To break this deadlock and allow the mode-switch registration to occur, purge all the usb-c-connector nodes' absent suppliers. This eliminates the connector as a supplier for a switch and allows it to be probed. Signed-off-by: Prashant Malani <pmalani@xxxxxxxxxxxx> Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx> Reviewed-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> Tested-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx> Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230331091145.737305-3-treapking@xxxxxxxxxxxx Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx> --- drivers/platform/chrome/cros_ec_typec.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c index 2b2f14a1b711..cc5269a4b2f1 100644 --- a/drivers/platform/chrome/cros_ec_typec.c +++ b/drivers/platform/chrome/cros_ec_typec.c @@ -325,6 +325,16 @@ static int cros_typec_init_ports(struct cros_typec_data *typec) return -EINVAL; } + /* + * OF graph may have set up some device links with switches, + * since connectors have their own compatible. Purge these + * to avoid a deadlock in switch probe (the switch mistakenly + * assumes the connector is a supplier). + */ + if (dev_of_node(dev)) + device_for_each_child_node(dev, fwnode) + fw_devlink_purge_absent_suppliers(fwnode); + /* DT uses "reg" to specify port number. */ port_prop = dev->of_node ? "reg" : "port-number"; device_for_each_child_node(dev, fwnode) { -- https://chromeos.dev
