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

[Moreno Bartalucci]

> Il giorno 12 mag 2017, alle ore 17:21, Bin Liu <b-...@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.

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.

Best regards,

Moreno