Re: [PATCH] usb: gadget: pch_udc: Convert to use GPIO descriptors

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Thu, Jul 16, 2020 at 01:19:32PM +0300, Andy Shevchenko wrote:
> On Thu, Jul 16, 2020 at 11:49 AM Linus Walleij <linus.walleij@linaro.org> wrote:
> > On Thu, Jul 2, 2020 at 4:57 PM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> >
> > > > Andy: your input would be appreciated, this kind of code
> > > > customizing random embedded Intel systems is deep water for
> > > > me, so this is just a rough guess on how it should be done.
> > >
> > > Linus, I have set up the device (it's actually available as Minnowboard v1) and
> > > will look at this.
> >
> > OK whenever you have time, there is no hurry.
> >
> > > For time being there is a patch you need to fold into this (sorry, it's mangled):
> > >
> > > (Explanation: GPIO will be locked with request_irq() call)
> >
> > I do not understand this, sadly. gpiod_lock_as_irq() will be called
> > indeed, but we are requesting it as input and keeping it as such
> > so this should be fine?
> 
> When you clean up GPIO at the same time you don't need to carry this
> memory and resource for the entire lifetime of the driver. When you
> lock it as IRQ the resource is not available to use by others anyway
> and will be requested whenever IRQ is requested. That's how I
> understand it. And to me it makes sense from a flexibility point of
> view and debugging perspective.

I looked closer to the code, it's using it as IRQ and as a GPIO (to know was it
rising or falling). Easier to leave as in your patch. Meanwhile I'm trying to
find some information about actual presence / use of VBUS on Intel Galileo Gen
2 and / or Minnowboard v1.0.

-- 
With Best Regards,
Andy Shevchenko