On 23/04/15 04:52, Peter Chen wrote:
> On Wed, Apr 22, 2015 at 03:42:32PM +0300, Roger Quadros wrote:
>>> So we will have a separate drd fsm file, and the CONFIG_USB_OTG
>>> and CONFIG_USB_OTG_FSM are not needed to be defined, right?
>>>
>>
>> for drd case CONFIG_USB_OTG_FSM is definitely not needed.
>> I'm not sure if we can operate dual-role without CONFIG_USB_OTG.
>> I was thinking of combining the OTG core functionality (drivers/usb/common/usb-otg.c)
>> with CONFIG_USB_OTG.
>>
>
> Ok, let's choose CONFIG_USB_OTG for both drd and usb fsm case.
> And we need to patch for hcd that only hnp supported hcd needs
> to request otg descriptor, etc.
Agreed. It makes things much simpler.
>
> For yesterday's back-compatible old otg device, we can add otg
> features to these drivers, the current behavior for these drivers
> is: if CONFIG_USB_OTG is defined, it is an otg device, we can just
> keep the behavior unchanging. If these drivers need to use OTG framework
> in future, it needs to update its platform data or dts.
Right.
>
> So, I prefer:
>
> - For switching the role through the ID pin devices, we doesn't need any otg
> features, so no otg dts properties are needed.(expect dr_mode = "otg")
> - For adp/srp/hnp supported devices, we need (partial) otg features, and
> the fsm (hardware or software) are needed, we need some otg dts
> properties we discussed before.
Agreed.
I will try to incorporate these points in v3 of this series.
cheers,
-roger
>
>
>>>
>>> static const struct usb_descriptor_header *otg_desc_20[] = {
>>> (struct usb_descriptor_header *) &(struct usb_otg_descriptor_20){
>>> .bLength = sizeof(struct usb_otg_descriptor_20),
>>> .bDescriptorType = USB_DT_OTG,
>>>
>>> /*
>>> * REVISIT SRP-only hardware is possible, although
>>> * it would not be called "OTG" ...
>>> */
>>> .bmAttributes = USB_OTG_SRP | USB_OTG_HNP,
>>> .bcdOTG = cpu_to_le16(0x0200),
>>> },
>>> NULL,
>>> };
>>
>> instead of hardcoding bmAttributes field, it must be obtained from the
>> appropriate data structure that was set by the controller driver
>> by reading DT and OTG hardware info.
>>
>>>
>>> During bind process:
>>>
>>> if (gadget_is_otg_13(c->cdev->gadget))
>>> c->descriptors = otg_desc_13;
>>> else if (gadget_is_otg_20(c->cdev->gadget))
>>> c->descriptors = otg_desc_20;
>>
>> Probably a helper utitily can do the necessary checks and build the
>> otg descriptor for us.
>> usb_otg_get_descriptor(c->descriptors);
>>
>> e.g. for OTG3.0 we have a new flag USB_OTG_RSP, and this helper
>> can be upgraded in the future.
>
> ok, it is the implementation detail.
>
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