Re: [linux-usb-devel] [PATCH] PXA27x UDC driver.

[Dmitry Krivoschekov <dmitry.krivoschekov@gmail.com>]

David Brownell wrote:
> On Thursday 28 June 2007, Rodolfo Giometti wrote:
>
>> As suggest by Leo let me propose to you my new patch for PXA27x UDC
>> support.
>>
>> Please, let me know what I have to do for kernel inclusion. :)
>
> Let's start with *JUST* a driver, not trying to update everything
> else in the USB Gadget stack so that it looks like it's designed
> specifically to handle all of Intel's design botches related to
> endpoint config ... and work worse for essentially everything else.
>
> (Unlike pretty much every other vendor, Intel wanted hardware config
> management. It was unusably buggy in pxa21x/25x/26x, and not much
> better in pxa27x.)
>
>
> So in technical terms, and to repeat what I've said before: just
> configure it to act more like a PXA 25x chip (no altsettings) and
> get it so it passes all the tests [1], modulo errata which have no
> workarounds

Other options are:

    1. pre-program endpoints so the setting covers all gadget
       configurations, it seems it's feasible. The only appreciable
       change is, CDC Ethernet config number should be 3 instead of 1.
       It should not break anything.

    2. Implement a FAKE call of GET_CONFIGURATION command so upon
       gadget binding you can issue the command and program endpoints
       according to the received gadget configuration.

Also, considering that PXA3XX processors include PXA27x-compatible
USB device controller it makes sense to develop a driver that
will support both processor families. Hopefully PXA3XX arch
support will be merged some day (the arch support has been already
submitted here, but I don't know about its current status).


Regards,
Dmitry

> ... then submit that. No epautoconfig updates, no
> patches to every gadget driver to cope with updated autoconfig.
>
> Once there's a basic working no-frills version merged, then we can
> talk about whether things in the rest of the stack should change
> to accomodate the bizarre concepts of this controller.
>
> - Dave
>
>
> [1] http://www.linux-usb.org/usbtest/
>