From mboxrd@z Thu Jan  1 00:00:00 1970
From: stephen.boyd@linaro.org (Stephen Boyd)
Date: Wed, 11 Jan 2017 16:19:53 -0800
Subject: [PATCH v6 23/25] usb: chipidea: Pullup D+ in device mode via phy
 APIs
In-Reply-To: <20170103065318.GB14542@b29397-desktop>
References: <20161228225711.698-1-stephen.boyd@linaro.org>
 <20161228225711.698-24-stephen.boyd@linaro.org>
 <20170103065318.GB14542@b29397-desktop>
Message-ID: <148418039309.32258.7247753739063801774@sboyd-linaro>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Quoting Peter Chen (2017-01-02 22:53:19)
> On Wed, Dec 28, 2016 at 02:57:09PM -0800, Stephen Boyd wrote:
> > If the phy supports it, call phy_set_mode() to pull up D+ when
> > required by setting the mode to PHY_MODE_USB_DEVICE. If we want
> > to remove the pullup, set the mode to PHY_MODE_USB_HOST.
> > 
[..]
> > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> > index 0d532a724d48..6d61fa0689b0 100644
> > --- a/drivers/usb/chipidea/udc.c
> > +++ b/drivers/usb/chipidea/udc.c
> > @@ -1609,10 +1610,15 @@ static int ci_udc_pullup(struct usb_gadget *_gadget, int is_on)
> >               return 0;
> >  
> >       pm_runtime_get_sync(&ci->gadget.dev);
> > -     if (is_on)
> > +     if (is_on) {
> > +             if (ci->phy)
> > +                     phy_set_mode(ci->phy, PHY_MODE_USB_DEVICE);
> >               hw_write(ci, OP_USBCMD, USBCMD_RS, USBCMD_RS);
> > -     else
> > +     } else {
> >               hw_write(ci, OP_USBCMD, USBCMD_RS, 0);
> > +             if (ci->phy)
> > +                     phy_set_mode(ci->phy, PHY_MODE_USB_HOST);
> > +     }
> >       pm_runtime_put_sync(&ci->gadget.dev);
> >  
> >       return 0;
> 
> Would you describe the use case for it? Why not adding it at
> role switch routine?
> 

This is about pulling up D+. The phy I have requires that we manually
pull up D+ by writing a ULPI register before we set the run/stop bit. I
thought it would be appropriate to do so in ci_udc_pullup(), where we're
supposed to put that pullup code, unless I'm mistaken?

It's not exactly about putting the phy into device or host mode, so
phy_set_mode() may not actually be the best API to use. Perhaps we need
some sort of phy_pullup_usb() API here?