Re: [PATCH v4 3/7] phy: Add set_mode callback

[David Lechner]

On 05/04/2016 01:39 PM, Bin Liu wrote:
> On Wed, May 04, 2016 at 01:20:36PM -0500, David Lechner wrote:
> > This is something I actually plan on using because the device I am
> > using (LEGO MINDSTORMS EV3) is not wired for OTG, so the callback is
> > needed to override the ID and VBUS signals when switching between
> > host and peripheral mode.
>
> Have you already tested this? I never tried changing mode via sysfs, but
> by quickly reviewing the code, I am wondering how it works. the core
> only calls ops->set_mode() but nothing else. To really switch the mode,
> the driver has to talk to the root hub, and manipulate the SESSION
> bit...

I have tested this now and it works. It works because by setting the 
mode, we are overriding the VBUS and ID signals, which in turn triggers 
interrupts. I have tested switching to both peripheral mode and host 
mode via sysfs. Host mode has some issues if you are using a 
self-powered device, but that is a bug in the da8xx glue layer and 
shouldn't hold up this patch series. Aside from that, it works exactly 
as expected.