linux-kernel - Re: [PATCH v2 16/16] usb: dwc3: enable usb suspend phy

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Date:	Fri, 24 Oct 2014 10:29:33 -0500
From:	Felipe Balbi <balbi@...com>
To:	Huang Rui <ray.huang@....com>
CC:	Felipe Balbi <balbi@...com>,
	Paul Zimmerman <Paul.Zimmerman@...opsys.com>,
	Alan Stern <stern@...land.harvard.edu>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Vincent Wan <vincent.wan@....com>, Tony Li <tony.li@....com>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 16/16] usb: dwc3: enable usb suspend phy

On Mon, Oct 20, 2014 at 05:01:25PM +0800, Huang Rui wrote:
> On Mon, Oct 20, 2014 at 04:41:54PM +0800, Huang Rui wrote:
> > On Fri, Oct 17, 2014 at 01:48:19PM -0500, Felipe Balbi wrote:
> > > Hi,
> > > 
> > > On Fri, Oct 17, 2014 at 06:41:04PM +0000, Paul Zimmerman wrote:
> > > > > From: Felipe Balbi [mailto:balbi@...com]
> > > > > Sent: Friday, October 17, 2014 8:00 AM
> > > > > 
> > > > > On Fri, Oct 17, 2014 at 04:53:41PM +0800, Huang Rui wrote:
> > > > > > AMD NL needs to suspend usb3 ss phy, but this doesn't enable on simulation
> > > > > > board.
> > > > > >
> > > > > > Signed-off-by: Huang Rui <ray.huang@....com>
> > > > > > ---
> > > > > >  drivers/usb/dwc3/core.c          | 7 ++++++-
> > > > > >  drivers/usb/dwc3/dwc3-pci.c      | 3 ++-
> > > > > >  drivers/usb/dwc3/platform_data.h | 1 +
> > > > > >  3 files changed, 9 insertions(+), 2 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > > > > > index 3ccfe41..4a98696 100644
> > > > > > --- a/drivers/usb/dwc3/core.c
> > > > > > +++ b/drivers/usb/dwc3/core.c
> > > > > > @@ -395,6 +395,9 @@ static void dwc3_phy_setup(struct dwc3 *dwc)
> > > > > >  	if (dwc->quirks & DWC3_QUIRK_TX_DEEPH)
> > > > > >  		reg |= DWC3_GUSB3PIPECTL_TX_DEEPH(1);
> > > > > >
> > > > > > +	if (dwc->quirks & DWC3_QUIRK_SUSPHY)
> > > > > 
> > > > > should be:
> > > > > 
> > > > > 	if (!dwc->suspend_usb3_phy_quirk)
> > > > > 
> > > > > > +		reg |= DWC3_GUSB3PIPECTL_SUSPHY;
> > > > > 
> > > > > IIRC, databook asks us to set that bit anyway, so the quirk is disabling
> > > > > that bit. Am I missing something ? Paul ?
> > > > 
> > > > It looks to me that Huang's patch is enabling that bit, not disabling
> > > > it.
> > > 
> > > right, but that's what's actually quirky right ? IIRC, Databook asks us
> > > to set usb2 and usb3 suspend phy bits and we're just not doing it.
> > > 
> > > > Currently the driver does not set either DWC3_GUSB3PIPECTL_SUSPHY or
> > > > DWC3_GUSB2PHYCFG_SUSPHY (unless it has been added by that big patch
> > > > series you just posted). According to the databook, both of those
> > > > bits should be set to 1 after the core initialization has completed.
> > > 
> > > there you go. So unless that quirk bit flag is set, we're safe of
> > > setting SUSPHY bit for everybody.
> > > 
> > 
> 
> I read the databook again, below words (DWC3_GUSB3PIPECTL_SUSPHY) is
> copied from databook:
> 
> For DRD/OTG configurations, it is recommended that this bit is set to‘
> 0’ during coreConsultant configuration. If it is set to ’1’, then the
> application should clear this bit after power-on reset. Application
> needs to set it to ’1’ after the core initialization is completed.
> For all other configurations, this bit can be set to ’1’ during core
> configuration.
> 
> I see it's recommended to set '0' if on DRD/OTG configuration.

0 at the beginning of probe() sequence so core can communicate with its
PHYs, then set it to one at the end of probe().

-- 
balbi

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