On Sun, 8 May 2005, David Brownell wrote:
> > > } else if (gadget_is_omap (gadget)) {
> > > device_desc.bcdDevice = __constant_cpu_to_le16 (0x0208);
> > > } else if (gadget_is_lh7a40x(gadget)) {
> > > device_desc.bcdDevice = __constant_cpu_to_le16 (0x0209);
> > > ...
> > > } else if (gadget_is_at91(gadget)) {
> > > device_desc.bcdDevice = __constant_cpu_to_le16 (0x0213);
> >
> > This section of code strikes me as an excellent candidate for a library
> > routine, since it's reused practically verbatim in a number of gadget
> > drivers.
>
> Yes and no. There'd still need to be code like that to detect
> cases like controllers that can't handle particular protocol
> features ... for example, altsettings and multiple interfaces,
> without both of which CDC Ethernet can't be supported. (All
> CDC devices, including ACM, need at least multiple interfaces.
> Unless you prefer to ignore the standards, like Belcarra.)
>
> The Ethernet driver also refuses to run with drivers it doesn't
> recognize, to prevent using the CDC subset with controllers
> that are functional enough to support CDC Ethernet. That logic
> isn't wholly amenable to a library function; but for now, it's
> the only gadget driver with that sort of issue.
g_file_storage also has its own special check for controllers that can't
halt bulk endpoints (right now I think SuperH is the only one). All these
things are of course special-case considerations, of one sort of another.
It's best just to leave them as they are.
> But in general I agree: it'd make sense to have something
> simple, even an inline in "gadget.h", return the 0..99 number
> that our current convention associates with a given controller.
That was pretty much what I had in mind too. While it wouldn't make a
noticeable difference to the object code, it sure would simplify
maintenance of the source.
Alan Stern
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