linux-kernel - RE: [PATCH v3] USB: PHY: Re-organize Tegra USB PHY driver

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Message-ID: <D958900912E20642BCBC71664EFECE3E6DDF601595@BGMAIL02.nvidia.com>
Date:	Mon, 24 Sep 2012 11:50:39 +0530
From:	Venu Byravarasu <vbyravarasu@...dia.com>
To:	"ABRAHAM, KISHON VIJAY" <kishon@...com>
CC:	Stephen Warren <swarren@...dotorg.org>,
	"balbi@...com" <balbi@...com>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>
Subject: RE: [PATCH v3] USB: PHY: Re-organize Tegra USB PHY driver

> -----Original Message-----
> From: ABRAHAM, KISHON VIJAY [mailto:kishon@...com]
> Sent: Monday, September 24, 2012 11:48 AM
> To: Venu Byravarasu
> Cc: Stephen Warren; balbi@...com; gregkh@...uxfoundation.org; linux-
> kernel@...r.kernel.org; linux-usb@...r.kernel.org
> Subject: Re: [PATCH v3] USB: PHY: Re-organize Tegra USB PHY driver
> 
> Hi,
> 
> On Sat, Sep 22, 2012 at 2:08 PM, Venu Byravarasu
> <vbyravarasu@...dia.com> wrote:
> >> -----Original Message-----
> >> From: Stephen Warren [mailto:swarren@...dotorg.org]
> >> Sent: Friday, September 21, 2012 9:45 PM
> >> To: ABRAHAM, KISHON VIJAY
> >> Cc: Venu Byravarasu; balbi@...com; gregkh@...uxfoundation.org; linux-
> >> kernel@...r.kernel.org; linux-usb@...r.kernel.org
> >> Subject: Re: [PATCH v3] USB: PHY: Re-organize Tegra USB PHY driver
> >>
> >> On 09/21/2012 07:09 AM, ABRAHAM, KISHON VIJAY wrote:
> >> > Hi,
> >> >
> >> > On Fri, Sep 21, 2012 at 5:50 PM, Venu Byravarasu
> >> <vbyravarasu@...dia.com> wrote:
> >> >> NVIDIA produces several Tegra SoCs viz Tegra20, Tegra30 etc.
> >> >> In order to support USB PHY drivers on these SoCs, existing
> >> >> PHY driver is split into SoC agnostic common USB PHY driver
> >> >> and Tegra20-specific USB phy driver. This will facilitate
> >> >> easy addition and deletion of phy drivers for Tegra SoCs.
> >>
> >> >> @@ -618,6 +618,9 @@ static int tegra_ehci_probe(struct
> platform_device
> >> *pdev)
> >> ...
> >> >>         pdata = pdev->dev.platform_data;
> >> >>         if (!pdata) {
> >>
> >> Some missing lines of context are:
> >>
> >>                 dev_err(&pdev->dev, "Platform data missing\n");
> >>                 return -EINVAL;
> >>         }
> >>
> >> ...
> >> >> +       params.mode = TEGRA_USB_PHY_MODE_HOST;
> >> >> +       params.config = pdata->phy_config;
> >> >
> >> > I fail to understand how pdata is not NULL in dt boot. I know i've
> >> > already given this comment and you replied that you dint see any
> >> > crash. But I'd like to know where and how pdata gets populated.
> >>
> >> In practice, the platform uses AUXDATA to provide platform data to the
> >> driver even when it's instantiated using device tree; see
> >> arch/arm/mach-tegra/board-dt-tegra20.c variables tegra_ehci*_pdata
> and
> >> tegra20_auxdata_lookup[].
> >>
> >> In the slightly (very very slightly, hopefully) longer term, I would
> >> like to completely remove the AUXDATA setup from board-dt-tegra20.c;
> >> tegra_ehci_probe() should do something like:
> >>
> >> pdata = pdev->dev.platform_data
> >> if (!pdata)
> >>     pdata = parse_pdata_from_dt();
> >> /* user didn't specify any in DT either */
> >> if (!pdata)
> >>     pdata = default_pdata_for_port();
> >>
> >> ... where perhaps the use of defaults could be folded into
> >> parse_pdata_from_dt().
> >
> >
> > Thanks Stephen for the detailed explanation.
> >
> > Kishon / Felipe,
> > Do you have any more questions in this related, before patch can be
> applied?
> 
> I don't have any further comments.
> 

Thanks Kishon for your quick response.
 

> Thanks
> Kishon
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