[Letux-kernel] gadget after suspend

[Andreas Kemnade]

On Tue, 16 Jan 2018 15:47:46 +0100
H. Nikolaus Schaller <hns at goldelico.com> wrote:

[...]
>
> >> Then I also have to ifdown usb0; ifup usb0 to make it work.
> >>   
> > ifdown usb0/ifup usb0 does rmmod/modprobe at your setup?   
> 
> yes
> 
> > That is why I was doing just ifconfig down/up  
> 
> this does not suffice for me to get a connection.
> 
Also 
echo peripheral > /sys/bus/platform/devices/musb-hdrc*/mode

seems to help. I do not know why yet.

> >   
> >> Exactly the same networking setup works on AM335x so this allows
> >> to isolate that issue to musb and twl4030-phy.
> >>   
> > Why? gta04 = musb + omap2430 glue + twl4030-phy
> > am335x = musb + am35xx glue + ?  
> 
> different musb version?
> 
> Maybe the "?" is the reason...
> Not unlikely.
> 
Well, interesting would be the combination musb + omap2430 glue + not
twl4030-phy.

> It is just called "TI PHY" on am33xx and has some control registers.
> 
> Well, what also could play a role is USB power detection
> (sequence) and signalling (twl interrupt handling).

Hmm, musb talking with twl is hidden. turning on DEBUG in musb_core.c
and phy-twl4030.c did not show up anything interesting.

But now I found out something interesting:
Setting MUSB_POWER_SOFTCONN and MUSB_DEVCTL_SESSION via devmem2 seems
to enable gadget. MUSB seems to know that there is vbus.

Normally these things should be reset in
musb_restore_context()
if they are set before suspend in the call to
musb_save_context().

So there are enough interersting things to debug and
I know where to dig further.

Regards,
Andreas