Hi Sherry,
[...]
AFAIK, U-Boot does not support runtime switching of USB port to host from device and vice versa. This is the case for existing driver like DWC3/MUSB etc.
Ideally we would need a role switch driver that unbinds and rebinds host vs device driver as when required based on U-Boot cmd or via an API (if required to be done during SPL stage etc).
I wonder if we can add two subnodes under the wrapper node as below, one bind to usb gadget driver and another bind to usb host driver. So if we want to use usb device, just call the gadget driver, and if want to use usb host, just call the host driver. The driver will probe correspond node. I'm not sure if it is feasible, what do you think about it?
usbss0: cdns_usb@4104000 { compatible = "ti,j721e-usb"; [....] usb0: usb@6010000 { /* xhci reg address*/ compatible = "cdns,usb3-1.0.1";dr_mode = "host"; [....] } usb1: usb@6020000 { /* dev reg address*/ compatible = "cdns,usb3-1.0.1"; dr_mode = "peripheral"; [....] } }
But this is not how DT would look in kernel. There will be single DT node representing both Host and Device node. DT repesentation should not be changed based on OS/bootloader, its HW description and must remain same. Unbinding host/gadget driver and rebinding with a different role should not be hard as the U-Boot core infrastructure exists.
Moreover if xhci reg and dev reg are separated into different nodes dont we still need access to OTG register block to switch b/w host and device mode?
Regards Vignesh
Best regards Sherry sun
Regards Vignesh
Best regards Sherry sun
JJ
Then when binding the wrapper node, it will hard-coded the two
subnodes
to different driver(gadge/host driver) according to the dr_mode property
in
nodes.
Do you think I understand it right?
Best regards Sherry sun
Best regards Sherry sun
> JJ > > > >>>>>>> + { } >>>>>>> +}; _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fl
ists.d&data=02%7C01%7Csherry.sun%40nxp.com%7C7d1d76a7124f4c3f e9
9d08d72d3ddf82%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63 70276
16080089878&sdata=70BPVQkomokcNpxsHRD3njfZQvuG51VSD1QKBjQ o1kA%3
D&reserved=0 enx.de%2Flistinfo%2Fu-
boot&data=02%7C01%7Csherry.sun%40nxp.com%7C35f1d34da1ea4b7
670ba08d72b823e9a%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7
C637025710721487079&sdata=Nfk0qWtSViz60wJHAOr2m5tgIwTWjNwI
GrNOxDH6HC0%3D&reserved=0
-- Regards Vignesh