Re: [PATCH v3] usb: dwc3: Add support for VBUS power control

[Mike Looijmans]

Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert


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On 27-07-2020 13:53, Mark Brown wrote:
> On Mon, Jul 27, 2020 at 01:50:26PM +0200, Mike Looijmans wrote:
> > Met vriendelijke groet / kind regards,
> >
> > Mike Looijmans
> > System Expert
>
> You probably want to remove your signature when replying to the list...
>
> > On 27-07-2020 12:23, Mark Brown wrote:
> > > On Sun, Jul 26, 2020 at 09:10:39AM +0200, Mike Looijmans wrote:
>
> > > > It's the 5V VBUS power for the USB "plug" that's being controlled here. It
> > > > must turned on when the controller is in "host" mode. Some boards arrange
> > > > this in hardware through the PHY, and some just don't have any control at
> > > > all and have it permanently on or off. On a board where the 5V is controlled
> > > > using a GPIO line or an I2C chip, this patch is required to make it work.
>
> > > That sounds like the driver should not be using _get_optional() then.
>
> > Making it mandatory would break most (read: all except Topic's) existing
> > boards as they won't have it in their devicetree. I'm perfectly okay with
> > that, but others might disagree.
>
> No, it wouldn't break them at all - they'd get a dummy regulator
> provided.

Ah, so *not* using _get_optional will yield the behaviour that I'd want. I'll 
test and make a v4 patch.