[PATCH v2 1/2] usb: ehci-exynos: Make provision for vdd regulators
Jingoo Han
jg1.han at samsung.com
Wed Jun 11 21:21:09 PDT 2014
On Thursday, June 12, 2014 12:39 AM, Alan Stern wrote:
> On Fri, 6 Jun 2014, Vivek Gautam wrote:
>
> > Facilitate getting required 3.3V and 1.0V VDD supply for
> > EHCI controller on Exynos.
> >
> > With patches for regulators' nodes merged in 3.15:
> > c8c253f ARM: dts: Add regulator entries to smdk5420
> > 275dcd2 ARM: dts: add max77686 pmic node for smdk5250,
> >
> > certain perripherals will now need to ensure that,
> > they request VDD regulators in their drivers, and enable
> > them so as to make them working.
>
> "Certain peripherals"? Don't you mean "certain controllers"?
>
> Does this mean some controllers don't need to use the VDD regulators?
>
> > @@ -193,7 +196,31 @@ static int exynos_ehci_probe(struct platform_device *pdev)
> >
> > err = exynos_ehci_get_phy(&pdev->dev, exynos_ehci);
> > if (err)
> > - goto fail_clk;
> > + goto fail_regulator1;
> > +
> > + exynos_ehci->vdd33 = devm_regulator_get(&pdev->dev, "vdd33");
> > + if (!IS_ERR(exynos_ehci->vdd33)) {
> > + err = regulator_enable(exynos_ehci->vdd33);
> > + if (err) {
> > + dev_err(&pdev->dev,
> > + "Failed to enable 3.3V Vdd supply\n");
> > + goto fail_regulator1;
> > + }
> > + } else {
> > + dev_warn(&pdev->dev, "Regulator 3.3V Vdd supply not found\n");
> > + }
>
> What if this is one of the controllers that don't need to use a VDD
> regulator? Do you really want to print out a warning in that case?
> Should you call devm_regulator_get_optional() instead?
I agree with Alan's suggestion. This warning message is not
proper, when USB controllers that don't need a VDD regulator
are used. The devm_regulator_get_optional() looks better.
Best regards,
Jingoo Han
More information about the linux-arm-kernel
mailing list