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

From: Mark Brown
Date: Mon Jul 27 2020 - 07:53:41 EST


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.

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