[PATCH v3] usb: dwc2: add bus suspend/resume for dwc2

[Doug Anderson]

Kever,

On Mon, Nov 10, 2014 at 5:09 AM, Kever Yang <kever.yang at rock-chips.com> wrote:
> Hcd controller needs bus_suspend/resume, dwc2 controller make
> root hub generate suspend/resume signal with hprt0 register
> when work in host mode.
> After the root hub enter suspend, we can make controller enter
> low power state with PCGCTL register.
>
> We also update the lx_state for hsotg state.
>
> This patch has tested on rk3288 with suspend/resume.
>
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> Acked-by: Paul Zimmerman <paulz at synopsys.com>
> ---
>
> Changes in v3:
> - remove CONFIG_PM macro for bus_suspend/resume
> - add PCGCTL operation for no device connect case
>
> Changes in v2:
> - update commit message
> - make dwc2 suspend/resume sourcecode work
>
>  drivers/usb/dwc2/hcd.c | 88 +++++++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 77 insertions(+), 11 deletions(-)

I would certainly appreciate confirmation, but my inclination is to
NAK this change due to the fact that it regresses functionality.  I
haven't done any serious review of it, but I've been testing it and it
appears to break hotplug.

Said another way, I did this:

1. Without this patch, I booted with a USB stick in.  It was detected.
I unplugged it, waited 5 seconds, and then plugged it back in.  The
USB stick was redetcted.

2. With this patch, I did the same thing.  The USB not redected after
plugging it back in.

-Doug