Re: [PATCH 1/5] usb: dwc3: exynos: Add support for SCLK present on Exynos7

From: Mark Rutland
Date: Tue Sep 02 2014 - 07:01:46 EST


On Tue, Sep 02, 2014 at 11:39:08AM +0100, Vivek Gautam wrote:
> Hi,
>
>
> On Fri, Aug 29, 2014 at 12:18 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> > On Thu, Aug 28, 2014 at 09:01:56AM +0100, Vivek Gautam wrote:
> >> Exynos7 also has a separate special gate clock going to the IP
> >> apart from the usual AHB clock. So add support for the same.
> >>
> >> Signed-off-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
> >> ---
> >> drivers/usb/dwc3/dwc3-exynos.c | 16 ++++++++++++++++
> >> 1 file changed, 16 insertions(+)
> >>
> >> diff --git a/drivers/usb/dwc3/dwc3-exynos.c b/drivers/usb/dwc3/dwc3-exynos.c
> >> index f9fb8ad..bab6395 100644
> >> --- a/drivers/usb/dwc3/dwc3-exynos.c
> >> +++ b/drivers/usb/dwc3/dwc3-exynos.c
> >> @@ -35,6 +35,7 @@ struct dwc3_exynos {
> >> struct device *dev;
> >>
> >> struct clk *clk;
> >> + struct clk *sclk;
> >> struct regulator *vdd33;
> >> struct regulator *vdd10;
> >> };
> >> @@ -141,10 +142,17 @@ static int dwc3_exynos_probe(struct platform_device *pdev)
> >> return -EINVAL;
> >> }
> >>
> >> + /* Exynos7 has a special gate clock going to this IP */
> >> + exynos->sclk = devm_clk_get(dev, "usbdrd30_sclk");
> >> + if (IS_ERR(exynos->sclk))
> >> + dev_warn(dev, "couldn't get sclk\n");
> >
> > Doesn't this introduce a pointless warning for Exynos SoCs other than
> > Exynos7?
>
> True, it will introduce an unnecessary warning for non-Exynos7 systems.
> I initially thought of introducing a compatible check for Exynos7-dwc3, but that
> way we may end up adding such checks for future SoCs which have similar
> controller but have some clock difference or some other small change, no ?

Perhaps. I don't know what your future hardware will look like.

Is the usbdrd30_sclk input unique to Exynos7, or was it previously there
but just without an input?

If the latter you could just reduce this to:

dev_info(dev, "no sclk specified");

Mark.
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