Documentation [1] states that the default value of the dr_mode property is "otg". It also isn't marked a mandatory node, so it may or may not be set. So, accordingly if dr_mode is not mentioned in the devicetree node, OTG mode must be assumed.
In this driver however, this case is not handled. If dr_mode is not mentioned, USB_DR_MODE_UNKNOWN is set. The logic implemented raises an error, instead of falling back to USB_DR_MODE_OTG. Correct this to conform to the specification. Link: https://elixir.bootlin.com/u-boot/v2025.10/source/dts/upstream/Bindings/usb/usb-drd.yaml#L23 [1] Signed-off-by: Kaustabh Chakraborty <[email protected]> --- drivers/usb/dwc3/dwc3-generic.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c index c09014aec60..1967594f48a 100644 --- a/drivers/usb/dwc3/dwc3-generic.c +++ b/drivers/usb/dwc3/dwc3-generic.c @@ -173,8 +173,8 @@ static int dwc3_generic_of_to_plat(struct udevice *dev) node = dev_ofnode(dev->parent); plat->dr_mode = usb_get_dr_mode(node); if (plat->dr_mode == USB_DR_MODE_UNKNOWN) { - pr_err("Invalid usb mode setup\n"); - return -ENODEV; + pr_info("No USB mode specified. Using 'otg'\n"); + plat->dr_mode = USB_DR_MODE_OTG; } } @@ -516,6 +516,10 @@ static int dwc3_glue_bind_common(struct udevice *parent, ofnode node) if (!dr_mode) dr_mode = usb_get_dr_mode(node); + /* usb mode must fallback to peripheral if not known */ + if (dr_mode == USB_DR_MODE_UNKNOWN) + dr_mode = USB_DR_MODE_OTG; + if (CONFIG_IS_ENABLED(DM_USB_GADGET) && (dr_mode == USB_DR_MODE_PERIPHERAL || dr_mode == USB_DR_MODE_OTG)) { debug("%s: dr_mode: OTG or Peripheral\n", __func__); -- 2.52.0
