[RFC] rpi: add support to enable usb power domain

[alex.aring@gmail.com (Alexander Aring)]

Hi,

On Thu, Oct 29, 2015 at 12:02:24PM -0700, Eric Anholt wrote:
> Alexander Aring <alex.aring@gmail.com> writes:
> 
> > This patch adds support for RPi several Power Domains and enable support
> > to enable the USB Power Domain when it's not enabled before.
> >
> > This patch based on Eric Anholt's patch to support Power Domains. He had
> > an issue about -EPROBE_DEFER inside the power domain subsystem, this
> > issue was solved by commit <311fa6a> ("PM / Domains: Return -EPROBE_DEFER
> > if we fail to init or turn-on domain").
> >
> > It was tested with barebox and the following scripts before booting
...
> > Third:
> > The barebox regulator doesn't support right now to enable/disable
> > regulators at runtime but I want to bring this mainline in the next
> > days. So you can't check yourself if the above scripts working right
> > now. I describe it here to show you what exactly I tested.
> >
> > changes since Eric Anholts "power domain" patch:
> >  - add for me all known power domains of the RPi, it contains the domains
> >    0 - 9.
> 
> Note: None of the power domain enums other than the ones I'd had in my
> patch are actually connected to anything in the firmware.  I don't think
> we should be adding them, given that.

Okay. Then it makes sense that I still accessing UART and SDHC when I
turn off the power.

In you patch you had SDHC, USB, DSI. Are you sure that SDHC power domain
has any effect, because I don't see any effect and can still access the
sd card.

I using "... firmware from 2015-10-28 17:06".

I would add the power-domains where we have currently an use-case for it
and this USB at the moment. Is this okay for you?

- Alex