linux-kernel - RE: [PATCH v4 2/2] usb: dwc2: add 'mode' which based on Kconfig select or dts setting

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Message-ID: <A2CA0424C0A6F04399FB9E1CD98E0304844C4A45@US01WEMBX2.internal.synopsys.com>
Date:	Wed, 6 Aug 2014 22:57:14 +0000
From:	Paul Zimmerman <Paul.Zimmerman@...opsys.com>
To:	Doug Anderson <dianders@...omium.org>,
	Kever Yang <kever.yang@...k-chips.com>
CC:	Heiko Stuebner <heiko@...ech.de>, Addy Ke <addy.ke@...k-chips.com>,
	"Eddie Cai" <cf@...k-chips.com>, Jianqun Xu <xjq@...k-chips.com>,
	Olof Johansson <olof@...om.net>,
	Sonny Rao <sonnyrao@...omium.org>, wulf <wulf@...k-chips.com>,
	lyz <lyz@...k-chips.com>, Jingoo Han <jg1.han@...sung.com>,
	han jiang <hj@...k-chips.com>,
	Tao Huang <huangtao@...k-chips.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Dinh Nguyen <dinguyen@...era.com>
Subject: RE: [PATCH v4 2/2] usb: dwc2: add 'mode' which based on Kconfig
 select or dts setting

> From: dianders@...gle.com [mailto:dianders@...gle.com] On Behalf Of Doug Anderson
> Sent: Wednesday, August 06, 2014 3:25 PM
> 
> On Tue, Aug 5, 2014 at 6:01 PM, Kever Yang <kever.yang@...k-chips.com> wrote:
> > According to the "dr_mode", the otg controller can work as
> > device role and host role. Some boards always want to use host mode
> > and some other boards want to use gadget mode. We use the dts setting
> > to set dwc2's mode, rather than fixing it to whatever hardware says.
> >
> > Signed-off-by: Kever Yang <kever.yang@...k-chips.com>
> > Acked-by: Paul Zimmerman <paulz@...opsys.com>
> > ---
> >
> > Changes in v4:
> > - From Doug's suggestion:
> >  -- remove dr_mode init from Kconfig code
> >  -- change the commit meesage
> >
> > Changes in v3:
> > - fix the odd spacing in dwc2_hsotg struct
> > - From Jingoo's suggestion:
> >     change the commit message
> > - add dr_mode init from Kconfig
> >
> > Changes in v2:
> > - put spaces around '+' operator
> > - expand the comment for dr_mode
> > - handle dr_mode is USB_DR_MODE_OTG
> >
> >  drivers/usb/dwc2/core.c     | 18 ++++++++++++++++++
> >  drivers/usb/dwc2/core.h     |  5 +++++
> >  drivers/usb/dwc2/platform.c |  4 ++++
> >  3 files changed, 27 insertions(+)
> 
> I think this patch still makes sense even though we don't have a
> combined driver yet.  Perhaps Paul or Dihn can confirm.

Yes, it should be fine.

> We could potentially do something based on KConfig (like you did in
> patch set #3), but it wouldn't really make sense to do that until
> after Dihn's work lands.
> 
> 
> > diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
> > index 27d2c9b..738bec2 100644
> > --- a/drivers/usb/dwc2/core.c
> > +++ b/drivers/usb/dwc2/core.c
> > @@ -118,6 +118,7 @@ static int dwc2_core_reset(struct dwc2_hsotg *hsotg)
> >  {
> >         u32 greset;
> >         int count = 0;
> > +       u32 gusbcfg;
> >
> >         dev_vdbg(hsotg->dev, "%s()\n", __func__);
> >
> > @@ -148,6 +149,23 @@ static int dwc2_core_reset(struct dwc2_hsotg *hsotg)
> >                 }
> >         } while (greset & GRSTCTL_CSFTRST);
> >
> > +       if (hsotg->dr_mode == USB_DR_MODE_HOST) {
> > +               gusbcfg = readl(hsotg->regs + GUSBCFG);
> > +               gusbcfg &= ~GUSBCFG_FORCEDEVMODE;
> > +               gusbcfg |= GUSBCFG_FORCEHOSTMODE;
> > +               writel(gusbcfg, hsotg->regs + GUSBCFG);
> > +       } else if (hsotg->dr_mode == USB_DR_MODE_PERIPHERAL) {
> > +               gusbcfg = readl(hsotg->regs + GUSBCFG);
> > +               gusbcfg &= ~GUSBCFG_FORCEHOSTMODE;
> > +               gusbcfg |= GUSBCFG_FORCEDEVMODE;
> > +               writel(gusbcfg, hsotg->regs + GUSBCFG);
> > +       } else if (hsotg->dr_mode == USB_DR_MODE_OTG) {
> > +               gusbcfg = readl(hsotg->regs + GUSBCFG);
> > +               gusbcfg &= ~GUSBCFG_FORCEHOSTMODE;
> > +               gusbcfg &= ~GUSBCFG_FORCEDEVMODE;
> > +               writel(gusbcfg, hsotg->regs + GUSBCFG);
> 
> I think the third case here won't be too useful until the combined
> driver, but it shouldn't hurt, right?

Right. For the existing drivers, it shouldn't change anything, since
nothing currently sets dr_mode. And with Kever's other patches, it
forces host mode on the Rockchip platform, which is all that is required
for now, if I understand correctly.

-- 
Paul