Re: [PATCH] usb: dwc3: core: continue probe even if usb3 phy is notavailable

[George Cherian]

On 6/26/2013 3:46 PM, Felipe Balbi wrote:
> Hi,
>
> On Wed, Jun 26, 2013 at 02:59:14PM +0530, George Cherian wrote:
> > There can be configurations in which DWC3 is hoooked up only to USB2 PHY.
> > In such cases we should not return -EPROBE_DEFER, rather continue probe
> > even if there is no USB3 PHY.
> >
> > Signed-off-by: George Cherian <george.cherian@xxxxxx>
> > ---
> >   drivers/usb/dwc3/core.c | 31 ++++++++++++++++++++++++-------
> >   1 file changed, 24 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index c35d49d..d5e6f3e 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -100,7 +100,9 @@ static void dwc3_core_soft_reset(struct dwc3 *dwc)
> >   	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
> >   
> >   	usb_phy_init(dwc->usb2_phy);
> > -	usb_phy_init(dwc->usb3_phy);
> > +
> > +	if (dwc->usb3_phy)
> > +		usb_phy_init(dwc->usb3_phy);
> I would feel more comfortable if you would move our maximum_speed module
> parameter to DT with a property such as:
>
> snps,maximum_speed = "highspeed";
>
> then on driver you could:
okay
> ret = of_property_read_string(np, "snps,maximum_speed", &maximum_speed);
> if (ret < 0)
> 	bailout();
>
> if (strncmp(maximum_speed, "superspeed", 10) == 0) {
> 	/* grab USB3 PHY, return EPROBE_DEFER if not found */
> 	grab_usb3_phy();
> }
>
> if ((strncmp(maximum_speed, "highspeed", 9) == 0) ||
> 	(strncmp(maximum_speed, "fullspeed", 9) == 0) ||
> 	(strncmp(maximum_speed, "lowspeed", 8) == 0)) {
> 	/* grab USB2 PHY, return EPROBE_DEFER if not found */
> 	grab_usb2_phy();
> }
>
> this way, we depend solely on setting maximum_speed to highspeed for
> AM437x :-)
In dra7xx one instance is superspeed and one instance highspeed.
> ps: don't forget to default to superspeed in case no property is passed.
okay
Regards
-George
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