r"""usb.core - Core USB features. This module exports: Device - a class representing a USB device. Configuration - a class representing a configuration descriptor. Interface - a class representing an interface descriptor. Endpoint - a class representing an endpoint descriptor. find() - a function to find USB devices. """ __author__ = 'Wander Lairson Costa' __all__ = ['Device', 'Configuration', 'Interface', 'Endpoint', 'find'] import array import util import copy import sys import operator import _interop _DEFAULT_TIMEOUT = 1000 def _set_attr(input, output, fields): for f in fields: setattr(output, f, int(getattr(input, f))) class _ResourceManager(object): def __init__(self, parent, dev, backend): self.backend = backend self._active_cfg_index = None self.dev = dev self.handle = None self._claimed_intf = _interop._set() self._alt_set = {} self._ep_type_map = {} def managed_open(self): if self.handle is None: self.handle = self.backend.open_device(self.dev) return self.handle def managed_close(self): if self.handle is not None: self.backend.close_device(self.handle) self.handle = None def managed_set_configuration(self, device, config): if config is None: cfg = device[0] elif isinstance(config, Configuration): cfg = config else: cfg = util.find_descriptor(device, bConfigurationValue=config) self.managed_open() self.backend.set_configuration(self.handle, cfg.bConfigurationValue) # cache the index instead of the object to avoid cyclic references # of the device and Configuration (Device tracks the _ResourceManager, # which tracks the Configuration, which tracks the Device) self._active_cfg_index = cfg.index # after changing configuration, out alternate setting and endpoint type caches # are not valid anymore self._ep_type_map.clear() self._alt_set.clear() def managed_claim_interface(self, device, intf): self.managed_open() if intf is None: cfg = self.get_active_configuration() i = cfg[(0,0)].bInterfaceNumber elif isinstance(intf, Interface): i = intf.bInterfaceNumber else: i = intf if i not in self._claimed_intf: self.backend.claim_interface(self.handle, i) self._claimed_intf.add(i) def managed_release_interface(self, device, intf): if intf is None: cfg = self.get_active_configuration(device) i = cfg[(0,0)].bInterfaceNumber elif isinstance(intf, Interface): i = intf.bInterfaceNumber else: i = intf if i in self._claimed_intf: self.backend.release_interface(self.handle, i) self._claimed_intf.remove(i) def managed_set_interface(self, device, intf, alt): if intf is None: i = self.get_interface(device, intf) elif isinstance(intf, Interface): i = intf else: cfg = self.get_active_configuration(device) if alt is not None: i = util.find_descriptor(cfg, bInterfaceNumber=intf, bAlternateSetting=alt) else: i = util.find_descriptor(cfg, bInterfaceNumber=intf) self.managed_claim_interface(device, i) if alt is None: alt = i.bAlternateSetting self.backend.set_interface_altsetting(self.handle, i.bInterfaceNumber, alt) self._alt_set[i.bInterfaceNumber] = alt def get_interface(self, device, intf): # TODO: check the viability of issuing a GET_INTERFACE # request when we don't have a alternate setting cached if intf is None: cfg = self.get_active_configuration(device) return cfg[(0,0)] elif isinstance(intf, Interface): return intf else: cfg = self.get_active_configuration(device) if intf in self._alt_set: return util.find_descriptor(cfg, bInterfaceNumber=intf, bAlternateSetting=self._alt_set[intf]) else: return util.find_descriptor(cfg, bInterfaceNumber=intf) def get_active_configuration(self, device): # TODO: when we haven't called managed_set_configuration, # issue a get_configuration request to discover the current configuration # See patch #283765. # Meanwhile, we just return # the first configuration found if self._active_cfg_index is None: cfg = device[0] self._active_cfg_index = cfg.index return cfg return device[self._active_cfg_index] def get_endpoint_type(self, device, address, intf): intf = self.get_interface(device, intf) key = (address, intf.bInterfaceNumber, intf.bAlternateSetting) try: return self._ep_type_map[key] except KeyError: e = util.find_descriptor(intf, bEndpointAddress=address) type = util.endpoint_type(e.bmAttributes) self._ep_type_map[key] = type return type def release_all_interfaces(self, device): claimed = copy.copy(self._claimed_intf) for i in claimed: self.managed_release_interface(device, i) def dispose(self, device, close_handle = True): self.release_all_interfaces(device) if close_handle: self.managed_close() self._ep_type_map.clear() self._alt_set.clear() self._active_cfg_index = None class USBError(IOError): r"""Exception class for USB errors. Backends must raise this exception when USB related errors occur. """ pass class Endpoint(object): r"""Represent an endpoint object. This class contains all fields of the Endpoint Descriptor according to the USB Specification. You may access them as class properties. For example, to access the field bEndpointAddress of the endpoint descriptor: >>> import usb.core >>> dev = usb.core.find() >>> for cfg in dev: >>> for i in cfg: >>> for e in i: >>> print e.bEndpointAddress """ def __init__(self, device, endpoint, interface = 0, alternate_setting = 0, configuration = 0): r"""Initialize the Endpoint object. The device parameter is the device object returned by the find() function. endpoint is the endpoint logical index (not the endpoint address). The configuration parameter is the logical index of the configuration (not the bConfigurationValue field). The interface parameter is the interface logical index (not the bInterfaceNumber field) and alternate_setting is the alternate setting logical index (not the bAlternateSetting value). Not every interface has more than one alternate setting. In this case, the alternate_setting parameter should be zero. By "logical index" we mean the relative order of the configurations returned by the peripheral as a result of GET_DESCRIPTOR request. """ self.device = device intf = Interface(device, interface, alternate_setting, configuration) self.interface = intf.bInterfaceNumber self.index = endpoint backend = device._ctx.backend desc = backend.get_endpoint_descriptor( device._ctx.dev, endpoint, interface, alternate_setting, configuration ) _set_attr( desc, self, ( 'bLength', 'bDescriptorType', 'bEndpointAddress', 'bmAttributes', 'wMaxPacketSize', 'bInterval', 'bRefresh', 'bSynchAddress' ) ) def write(self, data, timeout = None): r"""Write data to the endpoint. The parameter data contains the data to be sent to the endpoint and timeout is the time limit of the operation. The transfer type and endpoint address are automatically inferred. The method returns the number of bytes written. For details, see the Device.write() method. """ return self.device.write(self.bEndpointAddress, data, self.interface, timeout) def read(self, size, timeout = None): r"""Read data from the endpoint. The parameter size is the number of bytes to read and timeout is the time limit of the operation.The transfer type and endpoint address are automatically inferred. The method returns an array.array object with the data read. For details, see the Device.read() method. """ return self.device.read(self.bEndpointAddress, size, self.interface, timeout) class Interface(object): r"""Represent an interface object. This class contains all fields of the Interface Descriptor according to the USB Specification. You may access them as class properties. For example, to access the field bInterfaceNumber of the interface descriptor: >>> import usb.core >>> dev = usb.core.find() >>> for cfg in dev: >>> for i in cfg: >>> print i.bInterfaceNumber """ def __init__(self, device, interface = 0, alternate_setting = 0, configuration = 0): r"""Initialize the interface object. The device parameter is the device object returned by the find() function. The configuration parameter is the logical index of the configuration (not the bConfigurationValue field). The interface parameter is the interface logical index (not the bInterfaceNumber field) and alternate_setting is the alternate setting logical index (not the bAlternateSetting value). Not every interface has more than one alternate setting. In this case, the alternate_setting parameter should be zero. By "logical index" we mean the relative order of the configurations returned by the peripheral as a result of GET_DESCRIPTOR request. """ self.device = device self.alternate_index = alternate_setting self.index = interface self.configuration = configuration backend = device._ctx.backend desc = backend.get_interface_descriptor( self.device._ctx.dev, interface, alternate_setting, configuration ) _set_attr( desc, self, ( 'bLength', 'bDescriptorType', 'bInterfaceNumber', 'bAlternateSetting', 'bNumEndpoints', 'bInterfaceClass', 'bInterfaceSubClass', 'bInterfaceProtocol', 'iInterface' ) ) def set_altsetting(self): r"""Set the interface alternate setting.""" self.device.set_interface_altsetting( self.bInterfaceNumber, self.bAlternateSetting ) def __iter__(self): r"""Iterate over all endpoints of the interface.""" for i in range(self.bNumEndpoints): yield Endpoint( self.device, i, self.index, self.alternate_index, self.configuration ) def __getitem__(self, index): r"""Return the Endpoint object in the given position.""" return Endpoint( self.device, index, self.index, self.alternate_index, self.configuration ) class Configuration(object): r"""Represent a configuration object. This class contains all fields of the Configuration Descriptor according to the USB Specification. You may access them as class properties. For example, to access the field bConfigurationValue of the configuration descriptor: >>> import usb.core >>> dev = usb.core.find() >>> for cfg in dev: >>> print cfg.bConfigurationValue """ def __init__(self, device, configuration = 0): r"""Initialize the configuration object. The device parameter is the device object returned by the find() function. The configuration parameter is the logical index of the configuration (not the bConfigurationValue field). By "logical index" we mean the relative order of the configurations returned by the peripheral as a result of GET_DESCRIPTOR request. """ self.device = device self.index = configuration backend = device._ctx.backend desc = backend.get_configuration_descriptor( self.device._ctx.dev, configuration ) _set_attr( desc, self, ( 'bLength', 'bDescriptorType', 'wTotalLength', 'bNumInterfaces', 'bConfigurationValue', 'iConfiguration', 'bmAttributes', 'bMaxPower' ) ) def set(self): r"""Set this configuration as the active one.""" self.device.set_configuration(self.bConfigurationValue) def __iter__(self): r"""Iterate over all interfaces of the configuration.""" for i in range(self.bNumInterfaces): alt = 0 try: while True: yield Interface(self.device, i, alt, self.index) alt += 1 except (USBError, IndexError): pass def __getitem__(self, index): r"""Return the Interface object in the given position. index is a tuple of two values with interface index and alternate setting index, respectivally. Example: >>> interface = config[(0, 0)] """ return Interface(self.device, index[0], index[1], self.index) class Device(object): r"""Device object. This class contains all fields of the Device Descriptor according to the USB Specification. You may access them as class properties. For example, to access the field bDescriptorType of the device descriptor: >>> import usb.core >>> dev = usb.core.find() >>> dev.bDescriptorType Additionally, the class provides methods to communicate with the hardware. Typically, an application will first call the set_configuration() method to put the device in a known configured state, optionally call the set_interface_altsetting() to select the alternate setting (if there is more than one) of the interface used, and call the write() and read() method to send and receive data. When working in a new hardware, one first try would be like this: >>> import usb.core >>> dev = usb.core.find(idVendor=myVendorId, idProduct=myProductId) >>> dev.set_configuration() >>> dev.write(1, 'teste') This sample finds the device of interest (myVendorId and myProductId should be replaced by the corresponding values of your device), then configures the device (by default, the configuration value is 1, which is a typical value for most devices) and then writes some data to the endpoint 0x01. Timeout values for the write, read and ctrl_transfer methods are specified in miliseconds. If the parameter is omitted, Device.default_timeout value will be used instead. This property can be set by the user at anytime. """ def __init__(self, dev, backend): r"""Initialize the Device object. Library users should normally get a Device instance through the find function. The dev parameter is the identification of a device to the backend and its meaning is opaque outside of it. The backend parameter is a instance of a backend object. """ self._ctx = _ResourceManager(self, dev, backend) self.__default_timeout = _DEFAULT_TIMEOUT desc = backend.get_device_descriptor(dev) _set_attr( desc, self, ( 'bLength', 'bDescriptorType', 'bcdUSB', 'bDeviceClass', 'bDeviceSubClass', 'bDeviceProtocol', 'bMaxPacketSize0', 'idVendor', 'idProduct', 'bcdDevice', 'iManufacturer', 'iProduct', 'iSerialNumber', 'bNumConfigurations' ) ) def set_configuration(self, configuration = None): r"""Set the active configuration. The configuration parameter is the bConfigurationValue field of the configuration you want to set as active. If you call this method without parameter, it will use the first configuration found. As a device hardly ever has more than one configuration, calling the method without parameter is enough to get the device ready. """ self._ctx.managed_set_configuration(self, configuration) def get_active_configuration(self): r"""Return a Configuration object representing the current configuration set.""" return self._ctx.get_active_configuration(self) def set_interface_altsetting(self, interface = None, alternate_setting = None): r"""Set the alternate setting for an interface. When you want to use an interface and it has more than one alternate setting, you should call this method to select the alternate setting you would like to use. If you call the method without one or the two parameters, it will be selected the first one found in the Device in the same way of set_configuration method. Commonly, an interface has only one alternate setting and this call is not necessary. For most of the devices, either it has more than one alternate setting or not, it is not harmful to make a call to this method with no arguments, as devices will silently ignore the request when there is only one alternate setting, though the USB Spec allows devices with no additional alternate setting return an error to the Host in response to a SET_INTERFACE request. If you are in doubt, you may want to call it with no arguments wrapped by a try/except clause: >>> try: >>> dev.set_interface_altsetting() >>> except usb.core.USBError: >>> pass """ self._ctx.managed_set_interface(self, interface, alternate_setting) def get_interface_altsetting(self, interface = None): r"""Get the active alternate setting of the given interface.""" return self._ctx.get_interface(self, interface) def reset(self): r"""Reset the device.""" self._ctx.dispose(self, False) self._ctx.backend.reset_device(self._ctx.handle) def write(self, endpoint, data, interface = None, timeout = None): r"""Write data to the endpoint. This method is used to send data to the device. The endpoint parameter corresponds to the bEndpointAddress member whose endpoint you want to communicate with. The interface parameter is the bInterfaceNumber field of the interface descriptor which contains the endpoint. If you do not provide one, the first one found will be used, as explained in the set_interface_altsetting() method. The data parameter should be a sequence like type convertible to array type (see array module). The timeout is specified in miliseconds. The method returns the number of bytes written. """ backend = self._ctx.backend fn_map = { util.ENDPOINT_TYPE_BULK:backend.bulk_write, util.ENDPOINT_TYPE_INTR:backend.intr_write, util.ENDPOINT_TYPE_ISO:backend.iso_write } intf = self._ctx.get_interface(self, interface) fn = fn_map[self._ctx.get_endpoint_type(self, endpoint, intf)] self._ctx.managed_claim_interface(self, intf) return fn( self._ctx.handle, endpoint, intf.bInterfaceNumber, array.array('B', data), self._get_timeout(timeout) ) def read(self, endpoint, size, interface = None, timeout = None): r"""Read data from the endpoint. This method is used to receive data from the device. The endpoint parameter corresponds to the bEndpointAddress member whose endpoint you want to communicate with. The interface parameter is the bInterfaceNumber field of the interface descriptor which contains the endpoint. If you do not provide one, the first one found will be used, as explained in the set_interface_altsetting() method. The size parameters tells how many bytes you want to read. The timeout is specified in miliseconds. The method returns an array object with the data read. """ backend = self._ctx.backend fn_map = { util.ENDPOINT_TYPE_BULK:backend.bulk_read, util.ENDPOINT_TYPE_INTR:backend.intr_read, util.ENDPOINT_TYPE_ISO:backend.iso_read } intf = self._ctx.get_interface(self, interface) fn = fn_map[self._ctx.get_endpoint_type(self, endpoint, intf)] self._ctx.managed_claim_interface(self, intf) return fn( self._ctx.handle, endpoint, intf.bInterfaceNumber, size, self._get_timeout(timeout) ) def ctrl_transfer(self, bmRequestType, bRequest, wValue=0, wIndex=0, data_or_wLength = None, timeout = None): r"""Do a control transfer on the endpoint 0. This method is used to issue a control transfer over the endpoint 0(endpoint 0 is required to always be a control endpoint). The parameters bmRequestType, bRequest, wValue and wIndex are the same of the USB Standard Control Request format. Control requests may or may not have a data payload to write/read. In cases which it has, the direction bit of the bmRequestType field is used to infere the desired request direction. For host to device requests (OUT), data_or_wLength parameter is the data payload to send, and it must be a sequence type convertible to an array object. In this case, the return value is the number of data payload written. For device to host requests (IN), data_or_wLength is the wLength parameter of the control request specifying the number of bytes to read in data payload. In this case, the return value is the data payload read, as an array object. """ if util.ctrl_direction(bmRequestType) == util.CTRL_OUT: if data_or_wLength is None: a = array.array('B') else: a = array.array('B', data_or_wLength) elif data_or_wLength is None: a = 0 else: a = data_or_wLength self._ctx.managed_open() return self._ctx.backend.ctrl_transfer( self._ctx.handle, bmRequestType, bRequest, wValue, wIndex, a, self._get_timeout(timeout) ) def is_kernel_driver_active(self, interface): r"""Determine if there is kernel driver associated with the interface. If a kernel driver is active, and the object will be unable to perform I/O. """ self._ctx.managed_open() return self._ctx.backend.is_kernel_driver_active(self._ctx.handle, interface) def detach_kernel_driver(self, interface): r"""Detach a kernel driver. If successful, you will then be able to perform I/O. """ self._ctx.managed_open() self._ctx.backend.detach_kernel_driver(self._ctx.handle, interface) def attach_kernel_driver(self, interface): r"""Re-attach an interface's kernel driver, which was previously detached using detach_kernel_driver().""" self._ctx.managed_open() self._ctx.backend.attach_kernel_driver(self._ctx.handle, interface) def __iter__(self): r"""Iterate over all configurations of the device.""" for i in range(self.bNumConfigurations): yield Configuration(self, i) def __getitem__(self, index): r"""Return the Configuration object in the given position.""" return Configuration(self, index) def __del__(self): self._ctx.dispose(self) def _get_timeout(self, timeout): if timeout is not None: return timeout return self.__default_timeout def __set_def_tmo(self, tmo): if tmo < 0: raise ValueError('Timeout cannot be a negative value') self.__default_timeout = tmo def __get_def_tmo(self): return self.__default_timeout default_timeout = property( __get_def_tmo, __set_def_tmo, doc = 'Default timeout for transfers' ) def find(find_all=False, backend = None, custom_match = None, **args): r"""Find an USB device and return it. find() is the function used to discover USB devices. You can pass as arguments any combination of the USB Device Descriptor fields to match a device. For example: find(idVendor=0x3f4, idProduct=0x2009) will return the Device object for the device with idVendor Device descriptor field equals to 0x3f4 and idProduct equals to 0x2009. If there is more than one device which matchs the criteria, the first one found will be returned. If a matching device cannot be found the function returns None. If you want to get all devices, you can set the parameter find_all to True, then find will return an list with all matched devices. If no matching device is found, it will return an empty list. Example: printers = find(find_all=True, bDeviceClass=7) This call will get all the USB printers connected to the system. (actually may be not, because some devices put their class information in the Interface Descriptor). You can also use a customized match criteria: dev = find(custom_match = lambda d: d.idProduct=0x3f4 and d.idvendor=0x2009) A more accurate printer finder using a customized match would be like so: def is_printer(dev): import usb.util if dev.bDeviceClass == 7: return True for cfg in dev: if util.find_descriptor(cfg, bInterfaceClass=7) is not None: return True printers = find(find_all=True, custom_match = is_printer) Now even if the device class code is in the interface descriptor the printer will be found. You can combine a customized match with device descriptor fields. In this case, the fields must match and the custom_match must return True. In the our previous example, if we would like to get all printers belonging to the manufacturer 0x3f4, the code would be like so: printers = find(find_all=True, idVendor=0x3f4, custom_match=is_printer) If you want to use find as a 'list all devices' function, just call it with find_all = True: devices = find(find_all=True) Finally, you may pass a custom backend to the find function: find(backend = MyBackend()) PyUSB has builtin backends for libusb 0.1, libusb 1.0 and OpenUSB. If you do not supply a backend explicitly, find() function will select one of the predefineds backends according to system availability. Backends are explained in the usb.backend module. """ def device_iter(k, v): for dev in backend.enumerate_devices(): d = Device(dev, backend) if (custom_match is None or custom_match(d)) and \ _interop._reduce( lambda a, b: a and b, map( operator.eq, v, map(lambda i: getattr(d, i), k) ), True ): yield d if backend is None: import backend.libusb10 as libusb10 import backend.libusb01 as libusb01 import backend.openusb as openusb for m in (libusb10, openusb, libusb01): backend = m.get_backend() if backend is not None: break else: raise ValueError('No backend is available in the system') k, v = args.keys(), args.values() if find_all: return [d for d in device_iter(k, v)] else: try: return device_iter(k, v).next() except StopIteration: return None