Re: [PATCH-v2 4/7] mmc: sdhci-pxav3: Add pinctl setting according to bus clock

[Vaibhav Hiremath]

On Tuesday 08 September 2015 03:34 PM, Jisheng Zhang wrote:
> On Tue, 8 Sep 2015 15:32:34 +0530
> Vaibhav Hiremath <vaibhav.hiremath@xxxxxxxxxx> wrote:
>
> > On Tuesday 08 September 2015 03:22 PM, Jisheng Zhang wrote:
> > > On Tue, 8 Sep 2015 15:04:41 +0530
> > > Vaibhav Hiremath <vaibhav.hiremath@xxxxxxxxxx> wrote:

<snip>

> > > > > >     static const struct sdhci_ops pxav3_sdhci_ops = {
> > > > > > @@ -586,6 +619,16 @@ static int sdhci_pxav3_probe(struct platform_device *pdev)
> > > > > >     		}
> > > > > >     	}
> > > > > >
> > > > > > +	pxa->pinctrl = devm_pinctrl_get(dev);
> > > > >
> > > > > could we ignore this for those SDHCI hosts that don't need it?
> > > >
> > > > Again, no need to introduce flags here. This is standard call and
> > > > handled properly. So for the platforms not using this, it really should
> > > > not matter.
> > > > Also, lookup is getting executed only when pinctrl is populated.
> > > >
> > > > So I do not see any need here.
> > > >
> > > > > > +	if (!IS_ERR(pxa->pinctrl)) {
> > > > > > +		pxa->pins_default = pinctrl_lookup_state(pxa->pinctrl, "default");
> > > > > > +		if (IS_ERR(pxa->pins_default))
> > > > > > +			dev_err(dev, "could not get default pinstate\n");
> > > > >
> > > > > Why those SDHCI hosts that don't need pinctl setting should got this error?
> > > >
> > > > It won't.
> > >
> > > It does. On Marvell Berlin SoCs, I got
> > >
> > > [    1.070000] sdhci-pxav3 f7ab0800.sdhci: could not get default pinstate
> > > [    1.080000] sdhci-pxav3 f7ab0800.sdhci: could not get fast pinstate
> > >
> > >
> > >
> > > > If Host does not need pinctrl, the execution would never reach this
> > > > point.
> > > > The if condition check would handle it, isn't it?
> > > >
> > > > 	pxa->pinctrl = devm_pinctrl_get(dev);
> > >
> > > It seems this function always succeed...
> >
> > Not always.
> > I would succeed only if you have pinctrl defined in DT for this device.
>
> Yes, that's what I thought, but I got
>
> [    1.070000] sdhci-pxav3 f7ab0800.sdhci: could not get default pinstate
> [    1.080000] sdhci-pxav3 f7ab0800.sdhci: could not get fast pinstate
>
> there's no pinctrl for f7ab0800.sdhci. Am I missing somthing?
>
> Thanks,
> Jisheng
>
> > And if you have pinctrl defined, isn't it is expected to have "default"
> > pin state to be always present?
> > And if answer is yes here, then it is fair to be prompting error for it.
> >
> > >   From another side, we may have default pin in dts, for example: pin muxed between
> > > emmc and nandflash. But we don't have fast pinstate, so we at least need the
> > > flag to fast pinstate. Otherwise, in such platforms, we could get something like
> >
> > That is exactly the reason behind keeping it as dev_info.
> >
> > > [    1.000000] sdhci-pxav3 f7ab0000.sdhci: get default pinstate
> > > [    1.000000] sdhci-pxav3 f7ab0000.sdhci: could not get fast pinstate

I did some invastigation here on the execution flow,
and you know what, you are right here.

It seems, devm_pinctrl_get() always returns valid pinctrl pointer, even
though the DT property is not populated.

The return value from I did some invastigation () should have been 
treated differently, but it is not. Instead it creates the
"struct pinctrl" and return back to the driver.

I am looping Linus Walleji here, probably he can comment/confirm on
this.


Thanks,
Vaibhav


> > Thanks,
> > Vaibhav
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