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* usb: musb: Disable pullup in gadget setup
@ 2019-04-30 15:10 ` Bin Liu
  0 siblings, 0 replies; 9+ messages in thread
From: Bin Liu @ 2019-04-30 15:10 UTC (permalink / raw)
  To: Paul Cercueil, od, linux-usb, linux-kernel

On Tue, Apr 30, 2019 at 10:05:06AM -0500, Bin Liu wrote:
> Hi Paul,
> 
> On Thu, Apr 04, 2019 at 11:10:46AM -0500, Bin Liu wrote:
> > On Thu, Apr 04, 2019 at 11:37:43AM +0200, Paul Cercueil wrote:
> > > The pullup may be already enabled before the driver is initialized.
> > > It has to be disabled at init time, as we cannot guarantee that a gadget
> > > driver will be bound to the UDC.
> > > 
> > > Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> > > ---
> > >  drivers/usb/musb/musb_gadget.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
> > > index ffe462a657b1..094dc59c834c 100644
> > > --- a/drivers/usb/musb/musb_gadget.c
> > > +++ b/drivers/usb/musb/musb_gadget.c
> > > @@ -1794,6 +1794,7 @@ int musb_gadget_setup(struct musb *musb)
> > >  
> > >  	musb->is_active = 0;
> > >  	musb_platform_try_idle(musb, 0);
> > > +	musb_pullup(musb, 0);
> > >  
> > >  	status = usb_add_gadget_udc(musb->controller, &musb->g);
> > >  	if (status)
> > 
> > Applied.
> 
> Sorry, I have dropped this patch from my tree. I realized the gadget
> core already defines callbacks to control the pullup. I think the
> proper fix should be calling usb_udc_vbus_handler() in musb gadget or
> glue layers.

Basically besides the problem your patch tries to fix, there is another
problem related to the pullup, which is enabled right after bind a
gadget driver, regardless of vbus status. This violates the USB Spec.
Implementing the udc core callbacks should fix both issues.

-Bin.

^ permalink raw reply	[flat|nested] 9+ messages in thread
* usb: musb: Disable pullup in gadget setup
@ 2019-04-04  9:37 ` Paul Cercueil
  0 siblings, 0 replies; 9+ messages in thread
From: Paul Cercueil @ 2019-04-04  9:37 UTC (permalink / raw)
  To: Bin Liu; +Cc: od, linux-usb, linux-kernel, Paul Cercueil

The pullup may be already enabled before the driver is initialized.
It has to be disabled at init time, as we cannot guarantee that a gadget
driver will be bound to the UDC.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/usb/musb/musb_gadget.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index ffe462a657b1..094dc59c834c 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -1794,6 +1794,7 @@ int musb_gadget_setup(struct musb *musb)
 
 	musb->is_active = 0;
 	musb_platform_try_idle(musb, 0);
+	musb_pullup(musb, 0);
 
 	status = usb_add_gadget_udc(musb->controller, &musb->g);
 	if (status)

^ permalink raw reply related	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2019-07-15  6:05 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2019-04-30 15:10 usb: musb: Disable pullup in gadget setup Bin Liu
2019-04-30 15:10 ` [PATCH] " Bin Liu
  -- strict thread matches above, loose matches on Subject: below --
2019-04-04  9:37 Paul Cercueil
2019-04-04  9:37 ` [PATCH] " Paul Cercueil
2019-04-04 16:10 ` Bin Liu
2019-04-04 16:10   ` [PATCH] " Bin Liu
2019-04-30 15:05   ` Bin Liu
2019-04-30 15:05     ` [PATCH] " Bin Liu
2019-07-15  6:05     ` Paul Cercueil

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