Re: [PATCH] usb-musb: keep VBUS on when device is disconnected

Bin Liu
2017-05-15T12:24:44Z

On Mon, May 15, 2017 at 09:07:10AM +0200, Moreno Bartalucci wrote:
>
> > Il giorno 12 mag 2017, alle ore 17:21, Bin Liu <b-liu@ti.com> ha scritto:
> >
> > […]
> >
> > Moreno, would you mind to test the patch below with your modem?
> >
> > […]
> >>
> >>> 8< --------------------
> >>> diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
> >>> index 9c7ee26ef388..465281244596 100644
> >>> --- a/drivers/usb/musb/musb_dsps.c
> >>> +++ b/drivers/usb/musb/musb_dsps.c
> >>> @@ -245,9 +245,14 @@ static int dsps_check_status(struct musb *musb, void *unused)
> >>> dsps_mod_timer_optional(glue);
> >>> break;
> >>> case OTG_STATE_A_WAIT_BCON:
> >>> + /* keep VBUS on for host-only mode */
> >>> + if (musb->port_mode == MUSB_PORT_MODE_HOST) {
> >>> + dsps_mod_timer_optional(glue);
> >>> + break;
> >>> + }
> >>> musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
> >>> skip_session = 1;
> >>> - /* fall */
> >>> + /* fall through */
> >>>
> >>> case OTG_STATE_A_IDLE:
> >>> case OTG_STATE_B_IDLE:
>
> Hello Bin,
>
> I tested the above patch with my device and it seems to work correctly with the current mainline kernel.
>
> I tested it with my “production” kernel as well (4.9.20) but, for it to work, I had to change it slightly.

Thanks for testing.

>
> This is what I tested for kernel 4.9.20:
>
> --- a/drivers/usb/musb/musb_dsps.c 2017-05-15 08:40:23.000000000 +0200
> +++ b/drivers/usb/musb/musb_dsps.c 2017-05-15 08:49:17.000000000 +0200
> @@ -213,6 +213,12 @@ static int dsps_check_status(struct musb
> msecs_to_jiffies(wrp->poll_timeout));
> break;
> case OTG_STATE_A_WAIT_BCON:
> + /* keep VBUS on for host-only mode */
> + if (musb->port_mode == MUSB_PORT_MODE_HOST) {
> + mod_timer(&glue->timer, jiffies +
> + msecs_to_jiffies(wrp->poll_timeout));
> + break;
> + }
> musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
> skip_session = 1;
> /* fall */
>
> In this form, it appears to work properly for 4.9.20 too.

Yeah, the mod_timer() call is wrapped into dsps_mod_timer_optional() by
369469a92393d ("usb: musb: Add support for optional VBUS irq to dsps
glue layer"), introduced in v4.11-rc1.

Regards,
-Bin.