Re: [PATCH v7 1/5] usb: dwc3: host: Set PHY mode during suspend

From: Matthias Kaehlcke <mka@chromium.org>
To: Felipe Balbi <balbi@kernel.org>
Cc: Sandeep Maheswaram <sanm@codeaurora.org>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Stephen Boyd <swboyd@chromium.org>,
	Doug Anderson <dianders@chromium.org>,
	linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Manu Gautam <mgautam@codeaurora.org>
Subject: Re: [PATCH v7 1/5] usb: dwc3: host: Set PHY mode during suspend
Date: Thu, 13 May 2021 07:37:03 -0700	[thread overview]
Message-ID: <YJ05j1ZQDREp4BQb@google.com> (raw)
In-Reply-To: <87wns27nlq.fsf@kernel.org>

On Thu, May 13, 2021 at 04:46:41PM +0300, Felipe Balbi wrote:
> 
> Hi,
> 
> Matthias Kaehlcke <mka@chromium.org> writes:
> >> > @@ -127,6 +142,50 @@ int dwc3_host_init(struct dwc3 *dwc)
> >> >  	return ret;
> >> >  }
> >> >  
> >> > +static void dwc3_set_phy_mode(struct usb_hcd *hcd)
> >> > +{
> >> > +
> >> > +	int i, num_ports;
> >> > +	u32 reg;
> >> > +	unsigned int ss_phy_mode = 0;
> >> > +	struct dwc3 *dwc = dev_get_drvdata(hcd->self.controller->parent);
> >> > +	struct xhci_hcd	*xhci_hcd = hcd_to_xhci(hcd);
> >> > +
> >> > +	dwc->hs_phy_mode = 0;
> >> > +
> >> > +	reg = readl(&xhci_hcd->cap_regs->hcs_params1);
> >> > +	num_ports = HCS_MAX_PORTS(reg);
> >> 
> >> there's a big assumption here that xhci is still alive. Why isn't this
> >> quirk implemented in xhci-plat itself?
> >
> > That should work for determining which types of devices are connected to
> > the PHYs, however IIUC the xhci-plat doesn't know about the PHY topology.
> > Are you suggesting to move that info into the xhci-plat driver so that it
> > can set the corresponding PHY modes?
> 
> Yes, if xHCI needs to know about PHYs in order to properly configure the
> PHYs, so be it :-)

Thanks for the confirmation, looks like we have a path forward here then :)