snd_uaudio with libusb ?

[Chuck T.]

> On 9/29/07, Chuck T. <freebsdfan at hotmail.com> wrote:
> >
> > >I think your device is a USB composite USB device with two
> > >interfaces (one for USB audio and the other for GPIO). How
> > >do you control the GPIO under Linux (by control transfer
> > >or interrupt/bulk transfer)? If the Linux application indeed
> > >works at the same time as the USB audio, then Linux
> > >does bind different driver to different interfaces (one for
> > >the usb audio interface and no driver for the GPIO interface).
> >
> > I talk to the GPIO bits via vendor specific requests to the control pipe.
> > I do a usb_open() when my application loads and never close it.  When I need
> > to set a GPIO bit I use usb_control_msg().  I've never "looked under the
> > covers" to see why it works, but it does.
> >
> 
> So this works under Linux but not FreeBSD. Maybe this is just a limitation
> of libusb under FreeBSD. Anyway, it is said that libusb is just a thin
> wrapper on top of USB. You may want to use the lower level api instead.



Yes I believe that is the case.  I'm hoping there is a simple fix that will allow

me to use libusb for OS portability.  I don't want to have to write OS specific

code if I can avoid it.  I've been using FreeBSD since the 1.0 and I really

want my app to run on FreeBSD but frankly 90% of the users will probably

be running on Linux anyway.


> I confess I do not know further (like how to bind ugen to individual interfaces
> and use IOCTL to perform usb transfer). But if post some codes,
> others may be able to help you.



Sure.  I doubt it will help as the problem is related to libusb but here's my code:



static usb_dev_handle *udev = NULL;



void UsbKeyRadio(int bKey)

{

   int ret;

   char Buf[2] = {0xff,0xff};



   if(bKey) {

   // Set PTT bit low

      Buf[0] = 0;

   }

   else {

   // Set PTT bit high

      Buf[0] = 0x20;

   }



   ret = usb_control_msg(udev,USB_TYPE_VENDOR,WRITE_GPIO,0,0,Buf,2,1000);

   if(ret != 2) {

      LOG_ERROR(("%s#%d: usb_control_msg returned %d (%s)\n",__FUNCTION__,

                 __LINE__,ret,Err2String(errno)));

   }

}



int UsbInit(void)

{

   struct usb_bus *bus;

   struct usb_device *dev = NULL;

   int Ret = ERR_USB_DEV_OPEN;   // assume the worse



   usb_init();

   usb_find_busses();

   usb_find_devices();



   for (bus = usb_busses; bus && dev == NULL; bus = bus->next) {

       for (dev = bus->devices; dev; dev = dev->next) {

          if(dev->descriptor.idVendor == 0x074d && 

             dev->descriptor.idProduct == 0x3556)

          {

             break;

          }

          else if(dev->descriptor.idVendor == 0x077d && 

             dev->descriptor.idProduct == 0x07af)

          {

             break;

          }

       }

   }



   if(dev != NULL) {

      if((udev = usb_open(dev)) != NULL) {

         Ret = 0;

      }

   }

   else {

      LOG_ERROR(("%s: USB device not found\n",__FUNCTION__));

   }



   return Ret;

}




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