linux-kernel - Re: [PATCH v2 2/3] usb: chipidea: Hook into mux framework to toggle usb switch

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Date:   Wed, 19 Jul 2017 10:05:26 +0800
From:   Peter Chen <hzpeterchen@...il.com>
To:     Stephen Boyd <stephen.boyd@...aro.org>
CC:     Peter Chen <Peter.Chen@....com>, <devicetree@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Rob Clark <robdclark@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        <devicetree@...r.infradead.org>,
        Andy Gross <andy.gross@...aro.org>,
        Peter Rosin <peda@...ntia.se>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 2/3] usb: chipidea: Hook into mux framework to toggle
 usb switch

On Tue, Jul 18, 2017 at 06:47:02PM -0700, Stephen Boyd wrote:
> Quoting Peter Chen (2017-07-17 21:41:11)
> > On Fri, Jul 14, 2017 at 02:40:04PM -0700, Stephen Boyd wrote:
> > >  
> > > @@ -175,6 +176,10 @@ static int host_start(struct ci_hdrc *ci)
> > >               if (ci_otg_is_fsm_mode(ci)) {
> > >                       otg->host = &hcd->self;
> > >                       hcd->self.otg_port = 1;
> > > +             } else {
> > > +                     ret = mux_control_select(ci->platdata->usb_switch, 1);
> > 
> > It is better to use MACRO for 1 and 0.
> > 
> 
> Ok.
> 
> > > +                     if (ret)
> > > +                             goto disable_reg;
> > >               }
> > >       }
> > >  
> > > @@ -195,6 +200,8 @@ static void host_stop(struct ci_hdrc *ci)
> > >       struct usb_hcd *hcd = ci->hcd;
> > >  
> > >       if (hcd) {
> > > +             if (!ci_otg_is_fsm_mode(ci))
> > > +                     mux_control_deselect(ci->platdata->usb_switch);
> > >               if (ci->platdata->notify_event)
> > >                       ci->platdata->notify_event(ci,
> > >                               CI_HDRC_CONTROLLER_STOPPED_EVENT);
> > > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> > > index d68b125796f9..deb18099e168 100644
> > > --- a/drivers/usb/chipidea/udc.c
> > > +++ b/drivers/usb/chipidea/udc.c
> > > @@ -22,6 +22,7 @@
> > >  #include <linux/usb/gadget.h>
> > >  #include <linux/usb/otg-fsm.h>
> > >  #include <linux/usb/chipidea.h>
> > > +#include <linux/mux/consumer.h>
> > >  
> > >  #include "ci.h"
> > >  #include "udc.h"
> > > @@ -1964,16 +1965,26 @@ void ci_hdrc_gadget_destroy(struct ci_hdrc *ci)
> > >  
> > >  static int udc_id_switch_for_device(struct ci_hdrc *ci)
> > >  {
> > > +     int ret = 0;
> > > +
> > >       if (ci->is_otg)
> > >               /* Clear and enable BSV irq */
> > >               hw_write_otgsc(ci, OTGSC_BSVIS | OTGSC_BSVIE,
> > >                                       OTGSC_BSVIS | OTGSC_BSVIE);
> > >  
> > > -     return 0;
> > > +     if (!ci_otg_is_fsm_mode(ci))
> > > +             ret = mux_control_select(ci->platdata->usb_switch, 0);
> > > +
> > > +     if (ci->is_otg && ret)
> > > +             hw_write_otgsc(ci, OTGSC_BSVIE | OTGSC_BSVIS, OTGSC_BSVIS);
> > 
> > Should use !ret?
> > 
> 
> No? This is intended to unwind the clearing and enabling of the BSV irq
> on failure (ret is non-zero) and so we clear and disable the BSV irq.

I see now, I did not notice we have already enabled BSV above.

-- 

Best Regards,
Peter Chen