La soluzione che ho implementato è quella di aprire il dispositivo USB utilizzando le API Java e quindi utilizzare il descrittore di file con libusb.Ho usato libusb dal progetto OpenNI da PrimeSense (https://github.com/OpenNI/OpenNI2)
bit codice:
di apertura del dispositivo (Uso sorso):
int LibUsbAndroid::android_open(libusb_device *device, libusb_device_handle **devHandle)
{
int fd = USBJNICallbacks::getCallback()->getDeviceFd(device->bus_number, device->device_address);
__android_log_print(ANDROID_LOG_VERBOSE,"USB","Got FD:%d",fd);
if(fd==-1)
{
__android_log_print(ANDROID_LOG_ERROR,"USB","android_open, bad fd");
return -1;
}
return libusb_open(device, devHandle, fd);
}
L'apertura del dispositivo in codice Java (non in esecuzione sul thread principale!):
public int getDeviceFd(int busNumber, int deviceAddress) {
UsbDevice device = findDevice(busNumber, deviceAddress);
if(device!=null)
{
mReceivedPermission = false;
PermissionRequester pr = new PermissionRequester(device);
pr.run();
if(!mUsbManager.hasPermission(device))
{
Log.v("USB", "Requesting permissiom to device");
mPermissionIntent = PendingIntent.getBroadcast(mContext, 0, new Intent(ACTION_USB_PERMISSION), 0);
IntentFilter filterPermission = new IntentFilter(ACTION_USB_PERMISSION);
mContext.registerReceiver(mUsbPermissionReceiver, filterPermission);
mUsbManager.requestPermission(device, mPermissionIntent);
}
else
{
Log.v("USB", "Already has permission");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
mReceivedPermission = true;
Log.v("USB", "Opening device");
OpenDevice od = openDevice(device);
Log.v("USB", "Adding to open devices");
mOpenDevices.put(""+busNumber+"/"+deviceAddress, od);
}
Log.v("USB", "Waiting for permission");
waitForPermissionResult();
OpenDevice od = mOpenDevices.get(""+busNumber+"/"+deviceAddress);
if(od!=null)
{
Log.v("USB", "Getting FD");
int result = od.mConnection.getFileDescriptor();
Log.i("USB","USB File desc:"+result);
return result;
}
else
{
Log.v("USB", "Error getting FD");
return -1;
}
}
return -1;
}
permesso codice di gestione:
privato BroadcastReceiver mUsbPermissionReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
Log.v("USB", "Received permission result");
String action = intent.getAction();
if (ACTION_USB_PERMISSION.equals(action)) {
synchronized (this) {
UsbDevice device = (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
Log.v("USB", "Received permission result OK");
if(device != null){
Log.v("USB", "Device OK");
mContext.unregisterReceiver(this);
Log.v("USB", "Openning device");
OpenDevice od = openDevice(device);
Log.v("USB", "Adding to open device list");
mOpenDevices.put(""+od.mBus+"/"+od.mAddress,od);
Log.v("USB", "Received permission is true");
mReceivedPermission = true;
}
else {
Log.d(TAG, "permission denied for device " + device);
}
}
}
}
}
};
Aperto funzione:
public OpenDevice openDevice(UsbDevice device) {
UsbDeviceConnection connection = mUsbManager.openDevice(device);
Log.i("USB","Device name="+device.getDeviceName());
int bus = getBusNumber(device.getDeviceName());
int address = getAddress(device.getDeviceName());
return new OpenDevice(device, connection, bus, address);
}
cambiamento lib USB (core.c):
int API_EXPORTED libusb_open(libusb_device *dev,
libusb_device_handle **handle, int fd)
{
struct libusb_context *ctx = DEVICE_CTX(dev);
struct libusb_device_handle *_handle;
size_t priv_size = usbi_backend->device_handle_priv_size;
int r;
usbi_dbg("open %d.%d", dev->bus_number, dev->device_address);
_handle = malloc(sizeof(*_handle) + priv_size);
if (!_handle)
return LIBUSB_ERROR_NO_MEM;
r = usbi_mutex_init(&_handle->lock, NULL);
if (r) {
free(_handle);
return LIBUSB_ERROR_OTHER;
}
_handle->dev = libusb_ref_device(dev);
_handle->claimed_interfaces = 0;
memset(&_handle->os_priv, 0, priv_size);
r = usbi_backend->open(_handle,fd);
if (r < 0) {
usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r);
libusb_unref_device(dev);
usbi_mutex_destroy(&_handle->lock);
free(_handle);
return r;
}
usbi_mutex_lock(&ctx->open_devs_lock);
list_add(&_handle->list, &ctx->open_devs);
usbi_mutex_unlock(&ctx->open_devs_lock);
*handle = _handle;
/* At this point, we want to interrupt any existing event handlers so
* that they realise the addition of the new device's poll fd. One
* example when this is desirable is if the user is running a separate
* dedicated libusb events handling thread, which is running with a long
* or infinite timeout. We want to interrupt that iteration of the loop,
* so that it picks up the new fd, and then continues. */
usbi_fd_notification(ctx);
return 0;
}
op_open (libusb_fs.c) cambio:
static int op_open(struct libusb_device_handle *handle, int fd)
{
struct linux_device_handle_priv *hpriv = _device_handle_priv(handle);
char filename[PATH_MAX];
_get_usbfs_path(handle->dev, filename);
usbi_dbg("opening %s", filename);
hpriv->fd = fd;
if (hpriv->fd < 0) {
if (errno == EACCES) {
usbi_err(HANDLE_CTX(handle), "libusb couldn't open USB device %s: "
"Permission denied.", filename);
usbi_err(HANDLE_CTX(handle),
"libusb requires write access to USB device nodes.");
return LIBUSB_ERROR_ACCESS;
} else if (errno == ENOENT) {
usbi_err(HANDLE_CTX(handle), "libusb couldn't open USB device %s: "
"No such file or directory.", filename);
return LIBUSB_ERROR_NO_DEVICE;
} else {
usbi_err(HANDLE_CTX(handle),
"open failed, code %d errno %d", hpriv->fd, errno);
return LIBUSB_ERROR_IO;
}
}
return usbi_add_pollfd(HANDLE_CTX(handle), hpriv->fd, POLLOUT);
}
Ecco un progetto chiamato libusbdroid http://sourceforge.net/projects/libusbdroid/. Come collegherò sispmctl e installarlo? – highsciguy