RE: [RFC PATCH v2 04/15] usb:cdns3: Driver initialization code.

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+ Tomek Klimek 

>> > +
>> > +static inline void cdns3_role_stop(struct cdns3 *cdns)
>> > +{
>> > +     enum cdns3_roles role = cdns->role;
>> > +
>> > +     if (role == CDNS3_ROLE_END)
>>
>> WARN_ON(role >= CNDS3_ROLE_END) ?
>>
>> > +             return;
>> > +
>> > +     mutex_lock(&cdns->mutex);
>> > +     cdns->roles[role]->stop(cdns);
>> > +     cdns->role = CDNS3_ROLE_END;
>>
>> Why change the role here? You are just stopping the role not changing it.
>> I think cdns->role should remain unchanged, so we can call cdns3_role_start()
>> if required without error.
>>
>
>The current version of this IP has some issues to detect vbus status correctly,
>we have to force vbus status accordingly, so we need a status to indicate
>vbus disconnection, and add some code to let controller know vbus
>removal, in that case, the controller's state machine can be correct.
>So, we increase one role 'CDNS3_ROLE_END' to for this purpose.

Hi, Tomek do you have any comment for this.
We have in RTL whole OTG machine and we can read all states. 

>From otg specification we have in otg_state such bits:
5:3	host_otg_state	"Current state of the OTG Host FSM.
3'b000 : H_IDLE
3'b001 : H_VBUS_ON
3'b010 : H_VBUS_FAILED
3'b011 : H_OTG_HOST_MODE
3'b100 : H_HOST_MODE
3'b101 : H_SWITCH_TO_DEVICE
3'b110 : H_A_SUSPEND
3'b111 : H_WAIT_VBUS_FALL"	RO	0x0
2:0	dev_otg_state	"Current state of the OTG Device FSM.
3'b000 : DEV_IDLE
3'b001 : DEV_MODE
3'b010 : DEV_SRP
3'b011 : DEV_WAIT_VBUS_FALL
3'b100 : DEV_SWITCH_TO_HOST
3'b101 : DEV_WAIT_FOR_CONN"

>
>CDNS3_ROLE_GADGET: gadget mode and VBUS on
>CDNS3_ROLE_HOST: host mode and VBUS on
>CDNS3_ROLE_END: VBUS off, eg either host or device cable on the port.
>
>So, we may start role from CDNS3_ROLE_END at probe when nothing is connected,
>and need to set role as CDNS3_ROLE_END at ->stop for further handling at
>role switch routine.
>

>> > +     mutex_unlock(&cdns->mutex);
>> > +}
>> > +
>> > +static enum cdns3_roles cdns3_get_role(struct cdns3 *cdns)
>> > +{
>> > +     if (cdns->roles[CDNS3_ROLE_HOST] && cdns->roles[CDNS3_ROLE_GADGET]) {
>> > +             //TODO: implements selecting device/host mode
>> > +             return CDNS3_ROLE_HOST;
>> > +     }
>> > +     return cdns->roles[CDNS3_ROLE_HOST]
>> > +             ? CDNS3_ROLE_HOST
>> > +             : CDNS3_ROLE_GADGET;

Cheers
Pawel,




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