Re: [RFC PATCH 9/9] usb: dwc2: Add gadget driver

[Jules Maselbas <jmaselbas@kalray.eu>]

Hi Sascha,

On Mon, Jan 27, 2020 at 02:40:34PM +0100, Sascha Hauer wrote:
> Hi Jules,
> > +int dwc2_gadget_init(struct dwc2 *dwc2)
> > +{
> > +	u32 dctl;
> > +	int epnum;
> > +	int ret;
> > +
> > +	dwc2_core_init(dwc2);
> 
> This is called once during probe here and once during host init, it
> should probably only be called once.
Yes this is called in both gadget and host init, the only difference is
that in host mode the mode is forced before. I still need see if the
force mode has to be set before the core_init.

The force mode is also kinda of a hack and I want to find a better way
of handling the case where the controller is otg but the connector is
not otg but host only.

For now I think it is okay to do the core_init in each mode, since otg mode is
not supported, you should either use the `usb` or the `usbgadget` command.

> 
> I would expect both host and gadget support to be optional, but instead
> both is unconditionally compiled in. Does this link when USB host or gadget
> support is disabled?
Good point, I forgot to do this. I've made the change locally this will be
included in the next version.

> How does the driver select between host and gadget mode? Normally we do
> not have any real OTG support in barebox. With dr_mode = "otg" in the
> device tree we usually register some device which the user can use to
> specify the mode during runtime. How is this solved here?
The selection is done with `usb` and `usbgadget` commands. The first will
call host_init which will "select" the host mode (by forcing the controller
mode to host). The later command will setup the controller in peripheral mode.

> Sascha
> 
> -- 
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox