""" Pythonic wrapper for libusb-1.0. The first thing you must do is to get an "USB context". To do so, create a LibUSBContext instance. Then, you can use it to browse available USB devices and open the one you want to talk to. At this point, you should have a USBDeviceHandle instance (as returned by LibUSBContext or USBDevice instances), and you can start exchanging with the device. Features: - Basic device settings (configuration & interface selection, ...) - String descriptor lookups (ASCII & unicode), and list supported language codes - Synchronous I/O (control, bulk, interrupt) - Asynchronous I/O (control, bulk, interrupt, isochronous) Note: Isochronous support is experimental. See USBPoller, USBTransfer and USBTransferHelper. """ import libusb1 from ctypes import byref, create_string_buffer, c_int, sizeof, POINTER, \ create_unicode_buffer, c_wchar, cast, c_uint16, c_ubyte, string_at, \ addressof, c_void_p, cdll from cStringIO import StringIO import sys from ctypes.util import find_library __all__ = ['LibUSBContext', 'USBDeviceHandle', 'USBDevice', 'USBPoller', 'USBTransfer', 'USBTransferHelper', 'EVENT_CALLBACK_SET'] if sys.version_info[:2] >= (2, 6): if sys.platform == 'win32': from ctypes import get_last_error as get_errno else: from ctypes import get_errno else: def get_errno(): raise NotImplementedError("Your python version doesn't support " "errno/last_error") __libc_name = find_library('c') if __libc_name is None: # Of course, will leak memory. # Should we warn user ? How ? _free = lambda x: None else: _free = getattr(cdll, __libc_name).free del __libc_name # Default string length # From a comment in libusb-1.0: "Some devices choke on size > 255" STRING_LENGTH = 255 EVENT_CALLBACK_SET = frozenset(( libusb1.LIBUSB_TRANSFER_COMPLETED, libusb1.LIBUSB_TRANSFER_ERROR, libusb1.LIBUSB_TRANSFER_TIMED_OUT, libusb1.LIBUSB_TRANSFER_CANCELLED, libusb1.LIBUSB_TRANSFER_STALL, libusb1.LIBUSB_TRANSFER_NO_DEVICE, libusb1.LIBUSB_TRANSFER_OVERFLOW, )) DEFAULT_ASYNC_TRANSFER_ERROR_CALLBACK = lambda x: False def create_binary_buffer(string_or_len): # Prevent ctypes from adding a trailing null char. if isinstance(string_or_len, basestring): result = create_string_buffer(string_or_len, len(string_or_len)) else: result = create_string_buffer(string_or_len) return result class USBTransfer(object): """ USB asynchronous transfer control & data. All modification methods will raise if called on a submitted transfer. Methods noted as "should not be called on a submitted transfer" will not prevent you from reading, but returned value is unspecified. """ # Prevent garbage collector from freeing the free function before our # instances, as we need it to property destruct them. __libusb_free_transfer = libusb1.libusb_free_transfer __libusb_cancel_transfer = libusb1.libusb_cancel_transfer __USBError = libusb1.USBError __LIBUSB_ERROR_NOT_FOUND = libusb1.LIBUSB_ERROR_NOT_FOUND __transfer = None __initialized = False __submitted = False __callback = None __ctypesCallbackWrapper = None def __init__(self, handle, iso_packets=0): """ You should not instanciate this class directly. Call "getTransfer" method on an USBDeviceHandle instance to get instances of this class. """ if iso_packets < 0: raise ValueError('Cannot request a negative number of iso ' 'packets.') self.__handle = handle self.__num_iso_packets = iso_packets result = libusb1.libusb_alloc_transfer(iso_packets) if not result: raise libusb1.USBError('Unable to get a transfer object') self.__transfer = result self.__ctypesCallbackWrapper = libusb1.libusb_transfer_cb_fn_p( self.__callbackWrapper) def close(self): """ Stop using this transfer. This removes some references to other python objects, to help garbage collection. Raises if called on a submitted transfer. This does not prevent future reuse of instance (calling one of "setControl", "setBulk", "setInterrupt" or "setIsochronous" methods will initialize it properly again), just makes it ready to be garbage-collected. It is not mandatory to call it either, if you have no problems with garbage collection. """ if self.__submitted: raise ValueError('Cannot close a submitted transfer') self.__initialized = False self.__callback = None def __del__(self): if self.__transfer is not None: try: # If this doesn't raise, we're doomed; transfer was submitted, # still python decided to garbage-collect this instance. # Stick to libusb's documentation, and don't free the # transfer. If interpreter is shutting down, kernel will # reclaim memory anyway. # Note: we can't prevent transfer's buffer from being # garbage-collected as soon as there will be no remaining # reference to transfer, so a segfault might happen anyway. # Should we warn user ? How ? self.cancel() except self.__USBError, exception: if exception.value == self.__LIBUSB_ERROR_NOT_FOUND: # Transfer was not submitted, we can free it. self.__libusb_free_transfer(self.__transfer) else: raise def __callbackWrapper(self, transfer_p): """ Makes it possible for user-provided callback to alter transfer when fired (ie, mark transfer as not submitted upon call). """ mine = addressof(self.__transfer.contents) his = addressof(transfer_p.contents) assert mine == his, (mine, his) self.__submitted = False callback = self.__callback if callback is not None: callback(self) def setCallback(self, callback): """ Change transfer's callback. """ if self.__submitted: raise ValueError('Cannot alter a submitted transfer') self.__callback = callback def getCallback(self): """ Get currently set callback. """ return self.__callback def setControl(self, request_type, request, value, index, buffer_or_len, callback=None, user_data=None, timeout=0): """ Setup transfer for control use. request_type, request, value, index: See USBDeviceHandle.controlWrite. buffer_or_len: either a string (when sending data), or expected data length (when receiving data) callback: function to call upon event. Called with transfer as parameter, return value ignored. user_data: to pass some data to/from callback timeout: in milliseconds, how long to wait for devices acknowledgement or data. Set to 0 to disable. """ if self.__submitted: raise ValueError('Cannot alter a submitted transfer') if isinstance(buffer_or_len, basestring): length = len(buffer_or_len) string_buffer = create_binary_buffer( ' ' * libusb1.LIBUSB_CONTROL_SETUP_SIZE + buffer_or_len) else: length = buffer_or_len string_buffer = create_binary_buffer(length + \ libusb1.LIBUSB_CONTROL_SETUP_SIZE) self.__initialized = False libusb1.libusb_fill_control_setup(string_buffer, request_type, request, value, index, length) libusb1.libusb_fill_control_transfer(self.__transfer, self.__handle, string_buffer, self.__ctypesCallbackWrapper, user_data, timeout) self.__callback = callback self.__initialized = True def setBulk(self, endpoint, buffer_or_len, callback=None, user_data=None, timeout=0): """ Setup transfer for bulk use. endpoint: endpoint to submit transfer to (implicitly sets transfer direction). buffer_or_len: either a string (when sending data), or expected data length (when receiving data) callback: function to call upon event. Called with transfer as parameter, return value ignored. user_data: to pass some data to/from callback timeout: in milliseconds, how long to wait for devices acknowledgement or data. Set to 0 to disable. """ if self.__submitted: raise ValueError('Cannot alter a submitted transfer') string_buffer = create_binary_buffer(buffer_or_len) self.__initialized = False libusb1.libusb_fill_bulk_transfer(self.__transfer, self.__handle, endpoint, string_buffer, sizeof(string_buffer), self.__ctypesCallbackWrapper, user_data, timeout) self.__callback = callback self.__initialized = True def setInterrupt(self, endpoint, buffer_or_len, callback=None, user_data=None, timeout=0): """ Setup transfer for interrupt use. endpoint: endpoint to submit transfer to (implicitly sets transfer direction). buffer_or_len: either a string (when sending data), or expected data length (when receiving data) callback: function to call upon event. Called with transfer as parameter, return value ignored. user_data: to pass some data to/from callback timeout: in milliseconds, how long to wait for devices acknowledgement or data. Set to 0 to disable. """ if self.__submitted: raise ValueError('Cannot alter a submitted transfer') string_buffer = create_binary_buffer(buffer_or_len) self.__initialized = False libusb1.libusb_fill_interrupt_transfer(self.__transfer, self.__handle, endpoint, string_buffer, sizeof(string_buffer), self.__ctypesCallbackWrapper, user_data, timeout) self.__callback = callback self.__initialized = True def setIsochronous(self, endpoint, buffer_or_len, callback=None, user_data=None, timeout=0, iso_transfer_length_list=None): """ Setup transfer for isochronous use. endpoint: endpoint to submit transfer to (implicitly sets transfer direction). buffer_or_len: either a string (when sending data), or expected data length (when receiving data) callback: function to call upon event. Called with transfer as parameter, return value ignored. user_data: to pass some data to/from callback timeout: in milliseconds, how long to wait for devices acknowledgement or data. Set to 0 to disable. iso_transfer_length_list: list of individual transfer sizes. If not provided, buffer_or_len's size will be divided evenly among the number of ISO transfers given to receive current instance, rounded down. Providing a list allows overriding this (both the number of ISO transfers and their individual lengths). """ if self.__submitted: raise ValueError('Cannot alter a submitted transfer') num_iso_packets = self.__num_iso_packets if num_iso_packets == 0: raise TypeError('This transfer canot be used for isochronous I/O. ' 'You must get another one with a non-zero iso_packets ' 'parameter.') string_buffer = create_binary_buffer(buffer_or_len) buffer_length = sizeof(string_buffer) if iso_transfer_length_list is None: iso_length = buffer_length / num_iso_packets iso_transfer_length_list = [iso_length for _ in xrange(num_iso_packets)] configured_iso_packets = len(iso_transfer_length_list) if configured_iso_packets > num_iso_packets: raise ValueError('Too many ISO transfer lengths (%i), there are ' 'only %i ISO transfers available' % (configured_iso_packets, num_iso_packets)) if sum(iso_transfer_length_list) > buffer_length: raise ValueError('ISO transfers too long (%i), there are only ' '%i bytes available' % (sum(iso_transfer_length_list), buffer_length)) transfer_p = self.__transfer self.__initialized = False libusb1.libusb_fill_iso_transfer(transfer_p, self.__handle, endpoint, string_buffer, buffer_length, num_iso_packets, self.__ctypesCallbackWrapper, user_data, timeout) for length, iso_packet_desc in zip(iso_transfer_length_list, libusb1.get_iso_packet_list(transfer_p)): if length <= 0: raise ValueError('Negative/null transfer length are not ' 'possible.') iso_packet_desc.length = length self.__callback = callback self.__initialized = True def getType(self): """ Get transfer type. See libusb1.libusb_transfer_type. """ return self.__transfer.contents.type def getEndpoint(self): """ Get endpoint. """ return self.__transfer.contents.endpoint def getStatus(self): """ Get transfer status. Should not be called on a submitted transfer. """ return self.__transfer.contents.status def getActualLength(self): """ Get actually transfered data length. Should not be called on a submitted transfer. """ return self.__transfer.contents.actual_length def getBuffer(self): """ Get data buffer content. Should not be called on a submitted transfer. """ transfer_p = self.__transfer transfer = transfer_p.contents if transfer.type == libusb1.LIBUSB_TRANSFER_TYPE_CONTROL: result = libusb1.libusb_control_transfer_get_data(transfer_p) else: result = string_at(transfer.buffer, transfer.length) return result def getISOBufferList(self): """ Get individual ISO transfer's buffer. Returns a list with one item per ISO transfer, with their individually-configured sizes. Should not be called on a submitted transfer. """ transfer_p = self.__transfer transfer = transfer_p.contents if transfer.type != libusb1.LIBUSB_TRANSFER_TYPE_ISOCHRONOUS: raise TypeError('This method cannot be called on non-iso ' 'transfers.') return libusb1.get_iso_packet_buffer_list(transfer_p) def getISOSetupList(self): """ Get individual ISO transfer's setup. Returns a list of dicts, each containing an individual ISO transfer parameters: - length - actual_length - status (see libusb1's API documentation for their signification) Should not be called on a submitted transfer (except for 'length' values). """ transfer_p = self.__transfer transfer = transfer_p.contents if transfer.type != libusb1.LIBUSB_TRANSFER_TYPE_ISOCHRONOUS: raise TypeError('This method cannot be called on non-iso ' 'transfers.') return [{ 'length': x.length, 'actual_length': x.actual_length, 'status': x.status, } for x in libusb1.get_iso_packet_list(transfer_p)] def setBuffer(self, buffer_or_len): """ Replace buffer with a new one. Allows resizing read buffer and replacing data sent. Note: resizing is not allowed for isochornous buffer (use setIsochronous). """ if self.__submitted: raise ValueError('Cannot alter a submitted transfer') transfer = self.__transfer.contents if transfer.type == libusb1.LIBUSB_TRANSFER_TYPE_CONTROL: raise ValueError('To alter control transfer buffer, use ' 'setControl') buff = create_binary_buffer(buffer_or_len) if transfer.type == libusb1.LIBUSB_TRANSFER_TYPE_ISOCHRONOUS and \ sizeof(buff) != transfer.length: raise ValueError('To alter isochronous transfer buffer length, ' 'use setIsochronous') transfer.buffer = cast(buff, c_void_p) transfer.length = sizeof(buff) def isSubmitted(self): """ Tells if this transfer is submitted and still pending. """ return self.__submitted def submit(self): """ Submit transfer for asynchronous handling. """ if self.__submitted: raise ValueError('Cannot submit a submitted transfer') if not self.__initialized: raise ValueError('Cannot submit a transfer until it has been ' 'initialized') self.__submitted = True result = libusb1.libusb_submit_transfer(self.__transfer) if result: self.__submitted = False raise libusb1.USBError(result) def cancel(self): """ Cancel transfer. Note: cancellation happens asynchronously, so you must wait for LIBUSB_TRANSFER_CANCELLED. """ result = self.__libusb_cancel_transfer(self.__transfer) if result: raise self.__USBError(result) self.__submitted = False class USBTransferHelper(object): """ Simplifies subscribing to the same transfer over and over, and callback handling: - no need to read event status to execute apropriate code, just setup different functions for each status code - just return True instead of calling submit Callbacks used in this class must follow the callback API described in USBTransfer, and are expected to return a boolean: - True if transfer is to be submitted again (to receive/send more data) - False otherwise """ # TODO: handle the special case of isochronous transfers, where there is a # global status and per-packet status. def __init__(self, transfer=None): """ Create a transfer callback dispatcher. transfer parameter is deprecated. If provided, it will be equivalent to: helper = USBTransferHelper() transfer.setCallback(helper) and also allows using deprecated methods on this class (otherwise, they raise AttributeError). """ if transfer is not None: # Deprecated: to drop self.__transfer = transfer transfer.setCallback(self) self.__event_callback_dict = {} self.__errorCallback = DEFAULT_ASYNC_TRANSFER_ERROR_CALLBACK def submit(self): """ Submit the asynchronous read request. Deprecated. Use submit on transfer. """ # Deprecated: to drop self.__transfer.submit() def cancel(self): """ Cancel a pending read request. Deprecated. Use cancel on transfer. """ # Deprecated: to drop self.__transfer.cancel() def setEventCallback(self, event, callback): """ Set a function to call for a given event. Possible event identifiers are listed in EVENT_CALLBACK_SET. """ if event not in EVENT_CALLBACK_SET: raise ValueError('Unknown event %r.' % (event, )) self.__event_callback_dict[event] = callback def setDefaultCallback(self, callback): """ Set the function to call for event which don't have a specific callback registered. The initial default callback does nothing and returns False. """ self.__errorCallback = callback def getEventCallback(self, event, default=None): """ Return the function registered to be called for given event identifier. """ return self.__event_callback_dict.get(event, default) def __call__(self, transfer): """ Callback to set on transfers. """ if self.getEventCallback(transfer.getStatus(), self.__errorCallback)( transfer): transfer.submit() def isSubmited(self): """ Returns whether this reader is currently waiting for an event. Deprecatd. Use isSubmitted on transfer. """ # Deprecated: to drop return self.__transfer.isSubmitted() class USBPoller(object): """ Class allowing integration of USB event polling in a file-descriptor monitoring event loop. """ def __init__(self, context, poller): """ Create a poller for given context. Warning: it will not check if another poller instance was already present for that context, and will replace it. poller is a polling instance implementing the following methods: - register(fd, event_flags) event_flags have the same meaning as in poll API (POLLIN & POLLOUT) - unregister(fd) - poll(timeout) timeout being a float in seconds, or None if there is no timeout. It must return a list of (descriptor, event) pairs. Note: USBPoller is itself a valid poller. """ self.__context = context self.__poller = poller self.__fd_set = set() context.setPollFDNotifiers(self._registerFD, self._unregisterFD) for fd, events in context.getPollFDList(): self._registerFD(fd, events) def __del__(self): self.__context.setPollFDNotifiers(None, None) def poll(self, timeout=None): """ Poll for events. timeout can be a float in seconds, or None for no timeout. Returns a list of (descriptor, event) pairs. """ next_usb_timeout = self.__context.getNextTimeout() if timeout is None: usb_timeout = next_usb_timeout elif next_usb_timeout: usb_timeout = min(next_usb_timeout, timeout) else: usb_timeout = timeout event_list = self.__poller.poll(usb_timeout) if event_list: fd_set = self.__fd_set result = [(x, y) for x, y in event_list if x not in fd_set] if len(result) != len(event_list): self.__context.handleEventsTimeout() else: result = event_list self.__context.handleEventsTimeout() return result def register(self, fd, events): """ Register an USB-unrelated fd to poller. Convenience method. """ if fd in self.__fd_set: raise ValueError('This fd is a special USB event fd, it cannot ' 'be polled.') self.__poller.register(fd, events) def unregister(self, fd): """ Unregister an USB-unrelated fd from poller. Convenience method. """ if fd in self.__fd_set: raise ValueError('This fd is a special USB event fd, it must ' 'stay registered.') self.__poller.unregister(fd) def _registerFD(self, fd, events, user_data=None): self.register(fd, events) self.__fd_set.add(fd) def _unregisterFD(self, fd, user_data=None): self.__fd_set.discard(fd) self.unregister(fd) class USBDeviceHandle(object): """ Represents an opened USB device. """ __handle = None __libusb_close = libusb1.libusb_close def __init__(self, context, handle): """ You should not instanciate this class directly. Call "open" method on an USBDevice instance to get an USBDeviceHandle instance. """ # XXX Context parameter is just here as a hint for garbage collector: # It must collect USBDeviceHandle instance before their LibUSBContext. self.__context = context self.__handle = handle def __del__(self): self.close() def close(self): """ Close this handle. If not called explicitely, will be called by destructor. """ handle = self.__handle if handle is not None: self.__libusb_close(handle) self.__handle = None def getConfiguration(self): """ Get the current configuration number for this device. """ configuration = c_int() result = libusb1.libusb_get_configuration(self.__handle, byref(configuration)) if result: raise libusb1.USBError(result) return configuration def setConfiguration(self, configuration): """ Set the configuration number for this device. """ result = libusb1.libusb_set_configuration(self.__handle, configuration) if result: raise libusb1.USBError(result) def claimInterface(self, interface): """ Claim (= get exclusive access to) given interface number. Required to receive/send data. """ result = libusb1.libusb_claim_interface(self.__handle, interface) if result: raise libusb1.USBError(result) def releaseInterface(self, interface): """ Release interface, allowing another process to use it. """ result = libusb1.libusb_release_interface(self.__handle, interface) if result: raise libusb1.USBError(result) def setInterfaceAltSetting(self, interface, alt_setting): """ Set interface's alternative setting (both parameters are integers). """ result = libusb1.libusb_set_interface_alt_setting(self.__handle, interface, alt_setting) if result: raise libusb1.USBError(result) def clearHalt(self, endpoint): """ Clear a halt state on given endpoint number. """ result = libusb1.libusb_clear_halt(self.__handle, endpoint) if result: raise libusb1.USBError(result) def resetDevice(self): """ Reinitialise current device. Attempts to restore current configuration & alt settings. If this fails, will result in a device diconnect & reconnect, so you have to close current device and rediscover it (notified by a LIBUSB_ERROR_NOT_FOUND error code). """ result = libusb1.libusb_reset_device(self.__handle) if result: raise libusb1.USBError(result) def kernelDriverActive(self, interface): """ Tell whether a kernel driver is active on given interface number. """ result = libusb1.libusb_kernel_driver_active(self.__handle, interface) if result == 0: is_active = False elif result == 1: is_active = True else: raise libusb1.USBError(result) return is_active def detachKernelDriver(self, interface): """ Ask kernel driver to detach from given interface number. """ result = libusb1.libusb_detach_kernel_driver(self.__handle, interface) if result: raise libusb1.USBError(result) def attachKernelDriver(self, interface): """ Ask kernel driver to re-attach to given interface number. """ result = libusb1.libusb_attach_kernel_driver(self.__handle, interface) if result: raise libusb1.USBError(result) def getSupportedLanguageList(self): """ Return a list of USB language identifiers (as integers) supported by current device for its string descriptors. """ descriptor_string = create_binary_buffer(STRING_LENGTH) result = libusb1.libusb_get_string_descriptor(self.__handle, 0, 0, descriptor_string, sizeof(descriptor_string)) if result < 0: if result == libusb1.LIBUSB_ERROR_PIPE: # From libusb_control_transfer doc: # control request not supported by the device return [] raise libusb1.USBError(result) length = cast(descriptor_string, POINTER(c_ubyte))[0] langid_list = cast(descriptor_string, POINTER(c_uint16)) result = [] append = result.append for offset in xrange(1, length / 2): append(libusb1.libusb_le16_to_cpu(langid_list[offset])) return result def getStringDescriptor(self, descriptor, lang_id): """ Fetch description string for given descriptor and in given language. Use getSupportedLanguageList to know which languages are available. Return value is an unicode string. Return None if there is no such descriptor on device. """ descriptor_string = create_unicode_buffer( STRING_LENGTH / sizeof(c_wchar)) result = libusb1.libusb_get_string_descriptor(self.__handle, descriptor, lang_id, descriptor_string, sizeof(descriptor_string)) if result == libusb1.LIBUSB_ERROR_NOT_FOUND: return None if result < 0: raise libusb1.USBError(result) return descriptor_string.value def getASCIIStringDescriptor(self, descriptor): """ Fetch description string for given descriptor in first available language. Return value is an ASCII string. Return None if there is no such descriptor on device. """ descriptor_string = create_binary_buffer(STRING_LENGTH) result = libusb1.libusb_get_string_descriptor_ascii(self.__handle, descriptor, descriptor_string, sizeof(descriptor_string)) if result == libusb1.LIBUSB_ERROR_NOT_FOUND: return None if result < 0: raise libusb1.USBError(result) return descriptor_string.value # Sync I/O def _controlTransfer(self, request_type, request, value, index, data, length, timeout): result = libusb1.libusb_control_transfer(self.__handle, request_type, request, value, index, data, length, timeout) if result < 0: raise libusb1.USBError(result) return result def controlWrite(self, request_type, request, value, index, data, timeout=0): """ Synchronous control write. request_type: request type bitmask (bmRequestType), see libusb1 constants LIBUSB_TYPE_* and LIBUSB_RECIPIENT_*. request: request id (some values are standard). value, index, data: meaning is request-dependent. timeout: in milliseconds, how long to wait for device acknowledgement. Set to 0 to disable. Returns the number of bytes actually sent. """ request_type = (request_type & ~libusb1.USB_ENDPOINT_DIR_MASK) | \ libusb1.LIBUSB_ENDPOINT_OUT data = create_binary_buffer(data) return self._controlTransfer(request_type, request, value, index, data, sizeof(data), timeout) def controlRead(self, request_type, request, value, index, length, timeout=0): """ Synchronous control read. timeout: in milliseconds, how long to wait for data. Set to 0 to disable. See controlWrite for other parameters description. Returns received data. """ request_type = (request_type & ~libusb1.USB_ENDPOINT_DIR_MASK) | \ libusb1.LIBUSB_ENDPOINT_IN data = create_binary_buffer(length) transferred = self._controlTransfer(request_type, request, value, index, data, length, timeout) return data.raw[:transferred] def _bulkTransfer(self, endpoint, data, length, timeout): transferred = c_int() result = libusb1.libusb_bulk_transfer(self.__handle, endpoint, data, length, byref(transferred), timeout) if result: raise libusb1.USBError(result) return transferred.value def bulkWrite(self, endpoint, data, timeout=0): """ Synchronous bulk write. endpoint: endpoint to send data to. data: data to send. timeout: in milliseconds, how long to wait for device acknowledgement. Set to 0 to disable. Returns the number of bytes actually sent. """ endpoint = (endpoint & ~libusb1.USB_ENDPOINT_DIR_MASK) | \ libusb1.LIBUSB_ENDPOINT_OUT data = create_binary_buffer(data) return self._bulkTransfer(endpoint, data, sizeof(data), timeout) def bulkRead(self, endpoint, length, timeout=0): """ Synchronous bulk read. timeout: in milliseconds, how long to wait for data. Set to 0 to disable. See bulkWrite for other parameters description. Returns received data. """ endpoint = (endpoint & ~libusb1.USB_ENDPOINT_DIR_MASK) | \ libusb1.LIBUSB_ENDPOINT_IN data = create_binary_buffer(length) transferred = self._bulkTransfer(endpoint, data, length, timeout) return data.raw[:transferred] def _interruptTransfer(self, endpoint, data, length, timeout): transferred = c_int() result = libusb1.libusb_interrupt_transfer(self.__handle, endpoint, data, length, byref(transferred), timeout) if result: raise libusb1.USBError(result) return transferred.value def interruptWrite(self, endpoint, data, timeout=0): """ Synchronous interrupt write. endpoint: endpoint to send data to. data: data to send. timeout: in milliseconds, how long to wait for device acknowledgement. Set to 0 to disable. Returns the number of bytes actually sent. """ endpoint = (endpoint & ~libusb1.USB_ENDPOINT_DIR_MASK) | \ libusb1.LIBUSB_ENDPOINT_OUT data = create_binary_buffer(data) return self._interruptTransfer(endpoint, data, sizeof(data), timeout) def interruptRead(self, endpoint, length, timeout=0): """ Synchronous interrupt write. timeout: in milliseconds, how long to wait for data. Set to 0 to disable. See interruptRead for other parameters description. Returns received data. """ endpoint = (endpoint & ~libusb1.USB_ENDPOINT_DIR_MASK) | \ libusb1.LIBUSB_ENDPOINT_IN data = create_binary_buffer(length) transferred = self._interruptTransfer(endpoint, data, length, timeout) return data.raw[:transferred] def getTransfer(self, iso_packets=0): """ Get an empty transfer for asynchronous use. iso_packets: the number of isochronous transfer descriptors to allocate. """ return USBTransfer(self.__handle, iso_packets) class USBDevice(object): """ Represents a USB device. """ __configuration_descriptor_list = None __libusb_unref_device = libusb1.libusb_unref_device __libusb_free_config_descriptor = libusb1.libusb_free_config_descriptor __byref = byref def __init__(self, context, device_p): """ You should not instanciate this class directly. Call LibUSBContext methods to receive instances of this class. """ # Important: device_p refcount must be incremented before being given # to this constructor. This class will decrement refcount upon # destruction. self.__context = context self.device_p = device_p # Fetch device descriptor device_descriptor = libusb1.libusb_device_descriptor() result = libusb1.libusb_get_device_descriptor(device_p, byref(device_descriptor)) if result: raise libusb1.USBError(result) self.device_descriptor = device_descriptor # Fetch all configuration descriptors self.__configuration_descriptor_list = [] append = self.__configuration_descriptor_list.append for configuration_id in xrange(device_descriptor.bNumConfigurations): config = libusb1.libusb_config_descriptor_p() result = libusb1.libusb_get_config_descriptor(device_p, configuration_id, byref(config)) if result == libusb1.LIBUSB_ERROR_NOT_FOUND: # Some devices (ex windows' root hubs) tell they have one # configuration, but they have no configuration descriptor. continue if result: raise libusb1.USBError(result) append(config.contents) def __del__(self): self.__libusb_unref_device(self.device_p) if self.__configuration_descriptor_list is not None: byref = self.__byref for config in self.__configuration_descriptor_list: self.__libusb_free_config_descriptor(byref(config)) def __str__(self): return 'Bus %03i Device %03i: ID %04x:%04x %s %s' % ( self.getBusNumber(), self.getDeviceAddress(), self.getVendorID(), self.getProductID(), self.getManufacturer(), self.getProduct() ) def reprConfigurations(self): """ Get a string representation of device's configurations. Note: opens the device temporarily. """ out = StringIO() for config in self.__configuration_descriptor_list: print >> out, 'Configuration %i: %s' % (config.bConfigurationValue, self._getASCIIStringDescriptor(config.iConfiguration)) print >> out, ' Max Power: %i mA' % (config.MaxPower * 2, ) # TODO: bmAttributes dump for interface_num in xrange(config.bNumInterfaces): interface = config.interface[interface_num] print >> out, ' Interface %i' % (interface_num, ) for alt_setting_num in xrange(interface.num_altsetting): altsetting = interface.altsetting[alt_setting_num] print >> out, ' Alt Setting %i: %s' % (alt_setting_num, self._getASCIIStringDescriptor(altsetting.iInterface)) print >> out, ' Class: %02x Subclass: %02x' % \ (altsetting.bInterfaceClass, altsetting.bInterfaceSubClass) print >> out, ' Protocol: %02x' % \ (altsetting.bInterfaceProtocol, ) for endpoint_num in xrange(altsetting.bNumEndpoints): endpoint = altsetting.endpoint[endpoint_num] print >> out, ' Endpoint %i' % (endpoint_num, ) print >> out, ' Address: %02x' % \ (endpoint.bEndpointAddress, ) attribute_list = [] transfer_type = endpoint.bmAttributes & \ libusb1.LIBUSB_TRANSFER_TYPE_MASK attribute_list.append(libusb1.libusb_transfer_type( transfer_type )) if transfer_type == \ libusb1.LIBUSB_TRANSFER_TYPE_ISOCHRONOUS: attribute_list.append(libusb1.libusb_iso_sync_type( (endpoint.bmAttributes & \ libusb1.LIBUSB_ISO_SYNC_TYPE_MASK) >> 2 )) attribute_list.append(libusb1.libusb_iso_usage_type( (endpoint.bmAttributes & \ libusb1.LIBUSB_ISO_USAGE_TYPE_MASK) >> 4 )) print >> out, ' Attributes: %s' % \ (', '.join(attribute_list), ) print >> out, ' Max Packet Size: %i' % \ (endpoint.wMaxPacketSize, ) print >> out, ' Interval: %i' % \ (endpoint.bInterval, ) print >> out, ' Refresh: %i' % \ (endpoint.bRefresh, ) print >> out, ' Sync Address: %02x' % \ (endpoint.bSynchAddress, ) return out.getvalue() def getBusNumber(self): """ Get device's bus number. """ return libusb1.libusb_get_bus_number(self.device_p) def getDeviceAddress(self): """ Get device's address on its bus. """ return libusb1.libusb_get_device_address(self.device_p) def getbcdUSB(self): """ Get the USB spec version device complies to, in BCD format. """ return self.device_descriptor.bcdUSB def getDeviceClass(self): """ Get device's class id. """ return self.device_descriptor.bDeviceClass def getDeviceSubClass(self): """ Get device's subclass id. """ return self.device_descriptor.bDeviceSubClass def getDeviceProtocol(self): """ Get device's protocol id. """ return self.device_descriptor.bDeviceProtocol def getMaxPacketSize0(self): """ Get device's max packet size for endpoint 0 (control). """ return self.device_descriptor.bMaxPacketSize0 def getVendorID(self): """ Get device's vendor id. """ return self.device_descriptor.idVendor def getProductID(self): """ Get device's product id. """ return self.device_descriptor.idProduct def getbcdDevice(self): """ Get device's release number. """ return self.device_descriptor.bcdDevice def getSupportedLanguageList(self): """ Get the list of language ids device has string descriptors for. """ temp_handle = self.open() return temp_handle.getSupportedLanguageList() def _getStringDescriptor(self, descriptor, lang_id): if descriptor == 0: result = None else: temp_handle = self.open() result = temp_handle.getStringDescriptor(descriptor, lang_id) return result def _getASCIIStringDescriptor(self, descriptor): if descriptor == 0: result = None else: temp_handle = self.open() result = temp_handle.getASCIIStringDescriptor(descriptor) return result def getManufacturer(self): """ Get device's manufaturer name. Note: opens the device temporarily. """ return self._getASCIIStringDescriptor( self.device_descriptor.iManufacturer) def getProduct(self): """ Get device's product name. Note: opens the device temporarily. """ return self._getASCIIStringDescriptor(self.device_descriptor.iProduct) def getSerialNumber(self): """ Get device's serial number. Note: opens the device temporarily. """ return self._getASCIIStringDescriptor( self.device_descriptor.iSerialNumber) def getNumConfigurations(self): """ Get device's number of possible configurations. """ return self.device_descriptor.bNumConfigurations def open(self): """ Open device. Returns an USBDeviceHandle instance. """ handle = libusb1.libusb_device_handle_p() result = libusb1.libusb_open(self.device_p, byref(handle)) if result: raise libusb1.USBError(result) return USBDeviceHandle(self.__context, handle) class LibUSBContext(object): """ libusb1 USB context. Provides methods to enumerate & look up USB devices. Also provides access to global (device-independent) libusb1 functions. """ __libusb_exit = libusb1.libusb_exit __context_p = None __added_cb = None __removed_cb = None def __init__(self): """ Create a new USB context. """ context_p = libusb1.libusb_context_p() result = libusb1.libusb_init(byref(context_p)) if result: raise libusb1.USBError(result) self.__context_p = context_p def __del__(self): self.exit() def exit(self): """ Close (destroy) this USB context. """ context_p = self.__context_p if context_p is not None: self.__libusb_exit(context_p) self.__context_p = None self.__added_cb = None self.__removed_cb = None def getDeviceList(self): """ Return a list of all USB devices currently plugged in, as USBDevice instances. """ device_p_p = libusb1.libusb_device_p_p() libusb_device_p = libusb1.libusb_device_p device_list_len = libusb1.libusb_get_device_list(self.__context_p, byref(device_p_p)) # Instanciate our own libusb_device_p object so we can free # libusb-provided device list. Is this a bug in ctypes that it doesn't # copy pointer value (=pointed memory address) ? At least, it's not so # convenient and forces using such weird code. result = [USBDevice(self, libusb_device_p(x.contents)) for x in device_p_p[:device_list_len]] libusb1.libusb_free_device_list(device_p_p, 0) return result def openByVendorIDAndProductID(self, vendor_id, product_id): """ Get the first USB device matching given vendor and product ids. Returns an USBDeviceHandle instance, or None if no present device match. """ handle_p = libusb1.libusb_open_device_with_vid_pid(self.__context_p, vendor_id, product_id) if handle_p: result = USBDeviceHandle(self, handle_p) else: result = None return result def getPollFDList(self): """ Return file descriptors to be used to poll USB events. You should not have to call this method, unless you are integrating this class with a polling mechanism. """ pollfd_p_p = libusb1.libusb_get_pollfds(self.__context_p) if not pollfd_p_p: errno = get_errno() if errno: raise OSError(errno) else: # Assume not implemented raise NotImplementedError("Your libusb doesn't seem to " "implement pollable FDs") try: result = [] append = result.append fd_index = 0 while pollfd_p_p[fd_index]: append((pollfd_p_p[fd_index].contents.fd, pollfd_p_p[fd_index].contents.events)) fd_index += 1 finally: _free(pollfd_p_p) return result def handleEvents(self): """ Handle any pending event (blocking). See libusb1 documentation for details (there is a timeout, so it's not "really" blocking). """ result = libusb1.libusb_handle_events(self.__context_p) if result: raise libusb1.USBError(result) def handleEventsTimeout(self, tv=0): """ Handle any pending event. If tv is 0, will return immediately after handling already-pending events. Othewire, defines the maximum amount of time to wait for events, in seconds. """ if tv is None: tv = 0 tv_s = int(tv) tv = libusb1.timeval(tv_s, int((tv - tv_s) * 1000000)) result = libusb1.libusb_handle_events_timeout(self.__context_p, byref(tv)) if result: raise libusb1.USBError(result) def setPollFDNotifiers(self, added_cb=None, removed_cb=None, user_data=None): """ Give libusb1 methods to call when it should add/remove file descriptor for polling. You should not have to call this method, unless you are integrating this class with a polling mechanism. """ if added_cb is None: added_cb = POINTER(None) else: added_cb = libusb1.libusb_pollfd_added_cb_p(added_cb) if removed_cb is None: removed_cb = POINTER(None) else: removed_cb = libusb1.libusb_pollfd_removed_cb_p(removed_cb) self.__added_cb = added_cb self.__removed_cb = removed_cb libusb1.libusb_set_pollfd_notifiers(self.__context_p, added_cb, removed_cb, user_data) def getNextTimeout(self): """ Returns the next internal timeout that libusb needs to handle, in seconds, or None if no timeout is needed. You should not have to call this method, unless you are integrating this class with a polling mechanism. """ timeval = libusb1.timeval() result = libusb1.libusb_get_next_timeout(self.__context_p, byref(timeval)) if result == 0: result = None elif result == 1: result = timeval.tv_sec + (timeval.tv_usec * 0.000001) else: raise libusb1.USBError(result) return result def setDebug(self, level): """ Set debugging level. Note: depending on libusb compilation settings, this might have no effect. """ libusb1.libusb_set_debug(self.__context_p, level)