[PATCH v6 01/11] drivers: usb: otg: add a new driver for omap usb2 phy

[ABRAHAM, KISHON VIJAY]

Hi Felipe,

On Mon, Aug 6, 2012 at 2:19 PM, Felipe Balbi <balbi at ti.com> wrote:
> Hi,
>
> On Fri, Aug 03, 2012 at 08:01:44PM +0530, ABRAHAM, KISHON VIJAY wrote:
>> >> +     return 0;
>> >> +}
>> >> +
>> >> +#ifdef CONFIG_PM_RUNTIME
>> >> +
>> >> +static int omap_usb2_runtime_suspend(struct device *dev)
>> >> +{
>> >> +     struct platform_device  *pdev = to_platform_device(dev);
>> >> +     struct omap_usb *phy = platform_get_drvdata(pdev);
>> >> +
>> >> +     clk_disable(phy->wkupclk);
>> >
>> > weird. I would expect the wakeup clock to be enabled on suspend and
>> > disabled on resume. Isn't this causing any unbalanced disable warnings ?
>>
>> Even I was expecting the wakeup clock to be enabled on suspend but if
>> we have this enabled coreaon domain is never
>> gated and core does not hit low power state. btw Why do think this is
>> unbalanced?
>
> because you never do a clk_enable() on probe(), so on your first
> suspend, you will disable the clock without having enabled it before,
> no? Unless pm_runtime forces a runtime_resume() when you call
> pm_runtime_enable()...
>
>> >> +static int omap_usb2_runtime_resume(struct device *dev)
>> >> +{
>> >> +     u32 ret = 0;
>> >> +     struct platform_device  *pdev = to_platform_device(dev);
>> >> +     struct omap_usb *phy = platform_get_drvdata(pdev);
>> >> +
>> >> +     ret = clk_enable(phy->wkupclk);
>> >> +     if (ret < 0)
>> >> +             dev_err(phy->dev, "Failed to enable wkupclk %d\n", ret);
>> >> +
>> >> +     return ret;
>> >> +}
>> >> +
>> >> +static const struct dev_pm_ops omap_usb2_pm_ops = {
>> >> +     SET_RUNTIME_PM_OPS(omap_usb2_runtime_suspend, omap_usb2_runtime_resume,
>> >> +             NULL)
>> >
>> > only runtime ? What about static suspend ? We need this to work also
>> > after a traditional echo mem > /sys/power/state ;-)
>>
>> The static suspend case is handled by users of this phy using
>> set_suspend hooks.
>
> I'm not sure if that's too wise, what if your user enabled USB, but
> for whatever reason loaded only the phy driver and not musb or dwc3. It
> will fail, right ?

The enabling and disabling of phy is solely governed by usb controller
driver (musb/dwc3). So if you dont have musb/dwc3 loaded, the phy will
be for sure disabled.

Thanks
Kishon