On Wed, May 18, 2016 at 03:45:11PM +0300, Roger Quadros wrote:
> On 18/05/16 06:18, Peter Chen wrote:
> > On Mon, May 16, 2016 at 12:51:53PM +0300, Roger Quadros wrote:
> >> On 16/05/16 12:23, Peter Chen wrote:
> >>> On Mon, May 16, 2016 at 11:26:57AM +0300, Roger Quadros wrote:
> >>>> Hi,
> >>>>
> >>>> On 16/05/16 10:02, Peter Chen wrote:
> >>>>> On Fri, May 13, 2016 at 01:03:27PM +0300, Roger Quadros wrote:
> >>>>>> +
> >>>>>> +static int usb_gadget_connect_control(struct usb_gadget *gadget, bool connect)
> >>>>>> +{
> >>>>>> + struct usb_udc *udc;
> >>>>>> +
> >>>>>> + mutex_lock(&udc_lock);
> >>>>>> + udc = usb_gadget_to_udc(gadget);
> >>>>>> + if (!udc) {
> >>>>>> + dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
> >>>>>> + __func__);
> >>>>>> + mutex_unlock(&udc_lock);
> >>>>>> + return -EINVAL;
> >>>>>> + }
> >>>>>> +
> >>>>>> + if (connect) {
> >>>>>> + if (!gadget->connected)
> >>>>>> + usb_gadget_connect(udc->gadget);
> >>>>>> + } else {
> >>>>>> + if (gadget->connected) {
> >>>>>> + usb_gadget_disconnect(udc->gadget);
> >>>>>> + udc->driver->disconnect(udc->gadget);
> >>>>>> + }
> >>>>>> + }
> >>>>>> +
> >>>>>> + mutex_unlock(&udc_lock);
> >>>>>> +
> >>>>>> + return 0;
> >>>>>> +}
> >>>>>> +
> >>>>>
> >>>>> Since this is called for vbus interrupt, why not using
> >>>>> usb_udc_vbus_handler directly, and call udc->driver->disconnect
> >>>>> at usb_gadget_stop.
> >>>>
> >>>> We can't assume that this is always called for vbus interrupt so
> >>>> I decided not to call usb_udc_vbus_handler.
> >>>>
> >>>> udc->vbus is really pointless for us. We keep vbus states in our
> >>>> state machine and leave udc->vbus as ture always.
> >>>>
> >>>> Why do you want to move udc->driver->disconnect() to stop?
> >>>> If USB controller disconnected from bus then the gadget driver
> >>>> must be notified about the disconnect immediately. The controller
> >>>> may or may not be stopped by the core.
> >>>>
> >>>
> >>> Then, would you give some comments when this API will be used?
> >>> I was assumed it is only used for drd state machine.
> >>
> >> drd_state machine didn't even need this API in the first place :).
> >> You guys wanted me to separate out start/stop and connect/disconnect for full OTG case.
> >> Won't full OTG state machine want to use this API? If not what would it use?
> >>
> >
> > Oh, I meant only drd and fully otg state machine needs it. I am
> > wondering if we need have a new API to do it. Two questions:
>
> OK.
> >
> > - Except for vbus interrupt, any chances this API will be used at
> > current logic?
>
> I don't think so. But we can't assume caller behaviour for any API.
>
> > - When this API is called but without a coming gadget->stop?
> >
> Never for DRD case. But we want to catch wrong users.
>
In future, otg_start_gadget will be used for both DRD and fully OTG FSM.
There is no otg_loc_conn at current DRD FSM, but there is
otg_loc_conn at current OTG FSM, see below.
DRD FSM:
case OTG_STATE_B_IDLE:
drd_set_protocol(fsm, PROTO_UNDEF);
otg_drv_vbus(otg, 0);
break;
case OTG_STATE_B_PERIPHERAL:
drd_set_protocol(fsm, PROTO_GADGET);
otg_drv_vbus(otg, 0);
break;
OTG FSM:
case OTG_STATE_B_IDLE:
otg_drv_vbus(otg, 0);
otg_chrg_vbus(otg, 0);
otg_loc_conn(otg, 0);
otg_loc_sof(otg, 0);
/*
* Driver is responsible for starting ADP probing
* if ADP sensing times out.
*/
otg_start_adp_sns(otg);
otg_set_protocol(fsm, PROTO_UNDEF);
otg_add_timer(otg, B_SE0_SRP);
break;
case OTG_STATE_B_PERIPHERAL:
otg_chrg_vbus(otg, 0);
otg_loc_sof(otg, 0);
otg_set_protocol(fsm, PROTO_GADGET);
otg_loc_conn(otg, 1);
break;
My original suggestion is to have an API to do pull dp and this API
will be used at both DRD and OTG FSM, and called at otg_loc_conn.
The (de)initialize is the same for both two FSMs, it both includes
init peripheral mode and pull up dp, and can be done by drd_set_protocol(fsm, PROTO_GADGET)
otg_loc_conn(otg, 1);
What do you think?
--
Best Regards,
Peter Chen
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