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SubjectRe: [RFC][PATCH 3/3] usb: dwc3: Registering a role switch in the DRD code.
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On 15/10/2019 22:10, John Stultz wrote:
> On Tue, Oct 15, 2019 at 1:25 AM Roger Quadros <rogerq@ti.com> wrote:
>> On 03/10/2019 02:16, John Stultz wrote:
>>> @@ -487,7 +539,28 @@ int dwc3_drd_init(struct dwc3 *dwc)
>>> if (IS_ERR(dwc->edev))
>>> return PTR_ERR(dwc->edev);
>>>
>>> - if (dwc->edev) {
>>> + if (device_property_read_bool(dwc->dev, "usb-role-switch")) {
>>
>> I think we should use role switch unconditionally and get rid of the
>> debugfs role status/change mechanism.
>>
>>> + struct usb_role_switch_desc dwc3_role_switch = {0};
>>> + u32 mode;
>>> +
>>> + if (device_property_read_bool(dwc->dev,
>>> + "role-switch-default-host")) {
>>> + dwc->role_switch_default_mode = USB_DR_MODE_HOST;
>>> + mode = DWC3_GCTL_PRTCAP_HOST;
>>> + } else {
>>> + dwc->role_switch_default_mode = USB_DR_MODE_PERIPHERAL;
>>> + mode = DWC3_GCTL_PRTCAP_DEVICE;
>>> + }
>>> + dwc3_role_switch.fwnode = dev_fwnode(dwc->dev);
>>> + dwc3_role_switch.set = dwc3_usb_role_switch_set;
>>> + dwc3_role_switch.get = dwc3_usb_role_switch_get;
>>> + dwc->role_sw = usb_role_switch_register(dwc->dev,
>>> + &dwc3_role_switch);
>>> + if (IS_ERR(dwc->role_sw))
>>> + return PTR_ERR(dwc->role_sw);
>>> +
>>> + dwc3_set_mode(dwc, mode);
>>> + } else if (dwc->edev) {
>>
>> Role switch should exist regardless if dwc->edev is present or not.
>
> Does that risk duplicative mode sets when things change (via the
> dwc3_drd_notifier and dwc3_usb_role_switch_set calls?).

Yes, we need to deal with it in the driver. e.g. in current case
when debugfs overrides a role from "otg" to "host" or "device",
we ignore the notifier.

Something similar could be done with role switch I think.

Felipe, what do you think?

--
cheers,
-roger
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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