On Mon, Apr 20, 2015 at 01:47:33PM +0800, Macpaul Lin wrote:
> Hi Peter,
>
> 2015-04-20 13:30 GMT+08:00 Peter Chen <peter.chen@xxxxxxxxxxxxx>:
> > On Thu, Apr 16, 2015 at 02:56:59PM +0800, Macpaul Lin wrote:
> >> Introduce kernel feature CONFIG_USB_OTG20 and related
> >> gadget_is_otg20() API for supporting OTG20 compliant
> >> drivers.
> >> This patch also updated usb_otg_descritpor.
> [Deleted]
> >
> > Do we really need another usb_otg_descritor20, how about define
> > otg descriptor like below:
> >
> > struct usb_otg_descriptor {
> > __u8 bLength;
> > __u8 bDescriptorType;
> >
> > __u8 bmAttributes; /* support for HNP, SRP, etc */
> > #ifdef CONFIG_USB_OTG20
> > __le16 bcdOTG; /* OTG release number */
> > #endif
> >
> > } __attribute__ ((packed));
>
> This is because some OTG-2.0 compatible OTG hardware might also
> compatible with OTG-1.3.
> These kind of hardware may have dynamic detection compatibility and
> could adjust their response timing at electrical level.
> These could be adjusted by register configuration after re-enumeration.
> Hence we may need to prepare OTG 1.3 and OTG 2.0 descriptors for these
> hardware which can do dynamic
> detection when the other A/B device will be connected.
Do we really have such requirement? I am assumed OTG version is static,
and decided by platform code. Felipe, do we really support that?
--
Best Regards,
Peter Chen
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