Re: [RFC] USB phy type C

[David Cohen <david.a.cohen@linux.intel.com>]

On Thu, Feb 12, 2015 at 12:45:53PM -0600, Felipe Balbi wrote:
> Hi,
> 
> On Thu, Feb 12, 2015 at 10:41:37AM -0800, David Cohen wrote:
> > Hi Felipe, et al,
> > 
> > Is there any on going discussion regarding to USB phy for type C connectors?
> > 
> > We'd like to know the community's preferable direction for handling
> > (still unsupported) cases like USB3.1 PD, Accessories and Alternate
> > modes as a new layer or an extension of current USB phy layer.
> > 
> > Comments are welcome :)
> 
> Not the USB phy layer, but the generic phy layer. All you need to do is
> add a new phy provider and add support for it from within dwc3.
> Something like below:
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 9f0e209b8f6c..55a85b40e43e 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -653,6 +653,19 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
>  		}
>  	}
>  
> +	dwc->usb3_typec_phy = devm_phy_get(dev, "usb3-typec-phy");
> +	if (IS_ERR(dwc->usb3_typec_phy)) {
> +		ret = PTR_ERR(dwc->usb3_typec_phy);
> +		if (ret == -ENOSYS || ret == -ENODEV) {
> +			dwc->usb3_typec_phy = NULL;
> +		} else if (ret == -EPROBE_DEFER) {
> +			return ret;
> +		} else {
> +			dev_err(dev, "no usb3 typeC phy, continuing without\n");
> +			dwc->usb3_typec_phy = NULL;
> +		}
> +	}
> +
>  	return 0;
>  }

Thanks. That's a nice direction.

>  
> 
> The only interesting part will be dealing with the other modes of
> operation, I haven't wrapped my head around it yet.

We'll probably get back to here with more questions/proposals about
that.

Br, David