[libhid-discuss] Paths to usage pages / python wrapper
Sarah Mount
s.mount at wlv.ac.uk
Wed Nov 12 16:28:01 UTC 2008
Hi all,
I'm using the SWIG/Python wrapper to libhid and just having some
trouble figuring out usage paths. The device I'm trying to communicate
with has the following parse tree:
parse tree of HIDInterface 005/007[0]:
path: 0xff000001.0xff000002; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00000000; type: 0xb0
path: 0xff000001.0x00010046.0x00010001; type: 0x80
path: 0xff000001.0x00010046.0x00010003; type: 0x80
path: 0xff000001.0x00010046.0x00010002; type: 0x80
Presumably anything with type 0xb0 can be used to set a feature
report? If I say something like:
path = (0xff000001, 0xff000002)
buffer = struct.pack('6b27x', 0x1, 0x1, 0x01, 0x01, 0x00, 0x02)
print 'Sending buffer of size %i to sensor: %s' % (len(buffer), repr(buffer))
ret = hid_set_output_report(hid, path, buffer)
if ret != HID_RET_SUCCESS:
sys.stderr.write("hid_dump_tree failed with return code %d.\n" % ret)
else: print 'Sent output report successfully!'
I get the following error:
Traceback (most recent call last):
File "./toradex.py", line 94, in <module>
main()
File "./toradex.py", line 54, in main
ret = hid_set_output_report(hid, path, buffer)
File "/var/lib/python-support/python2.5/hid/__init__.py", line 206,
in hid_set_output_report
return _hid.hid_set_output_report(*args)
ValueError: Expecting a sequence of integers
Presumably because the path in question was a sequence of longs. I'm
not sure whether the problem here is my understanding of the way paths
work in HID or something else! I'd be very grateful if anyone can
point me in the right direction. (output of lsusb listed below, in
case it's helpful).
Very many thanks,
Sarah
Output of `lsusb -d 0x1b67:0x0001 -vvv`
Bus 003 Device 008: ID 1b67:0001
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x1b67
idProduct 0x0001
bcdDevice 1.00
iManufacturer 1 Toradex
iProduct 2 Humidity Sensor
iSerial 3 T83310006
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 32mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 2 Humidity Sensor
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.11
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 112
Report Descriptor: (length is 112)
Item(Global): Usage Page, data= [ 0x00 0xff ] 65280
(null)
Item(Local ): Usage, data= [ 0x01 ] 1
(null)
Item(Main ): Collection, data= [ 0x01 ] 1
Application
Item(Global): Report Size, data= [ 0x08 ] 8
Item(Global): Report Count, data= [ 0x20 ] 32
Item(Global): Logical Minimum, data= [ 0x00 ] 0
Item(Global): Logical Maximum, data= [ 0xff 0x00 ] 255
Item(Local ): Usage, data= [ 0x02 ] 2
(null)
Item(Main ): Feature, data= [ 0xe2 0x01 ] 482
Data Variable Absolute No_Wrap Linear
No_Preferred_State Null_State Volatile Buffered Bytes
Item(Global): Usage Page, data= [ 0x01 ] 1
Generic Desktop Controls
Item(Local ): Usage, data= [ 0x46 ] 70
Vector
Item(Main ): Collection, data= [ 0x02 ] 2
Logical
Item(Global): Logical Minimum, data= [ 0x00 ] 0
Item(Global): Logical Maximum, data= [ 0xff 0x07 ] 2047
Item(Global): Physical Minimum, data= [ 0x00 ] 0
Item(Global): Physical Maximum, data= [ 0xff 0x07 ] 2047
Item(Global): Unit, data= [ 0x01 0x10 ] 4097
System: SI Linear, Unit: Seconds
Item(Global): Unit Exponent, data= [ 0x0d ] 13
Unit Exponent: 13
Item(Global): Report Size, data= [ 0x10 ] 16
Item(Global): Report Count, data= [ 0x01 ] 1
Item(Local ): Usage, data= [ 0x01 ] 1
Pointer
Item(Local ): String Index, data= [ 0x04 ] 4
Item(Main ): Input, data= [ 0xea 0x01 ] 490
Data Variable Absolute Wrap Linear
No_Preferred_State Null_State Volatile Buffered Bytes
Item(Global): Logical Minimum, data= [ 0x00 ] 0
Item(Global): Logical Maximum, data= [ 0x10 0x27 ] 10000
Item(Global): Physical Minimum, data= [ 0x00 ] 0
Item(Global): Physical Maximum, data= [ 0x10 0x27 ] 10000
Item(Global): Unit, data= [ 0x00 ] 0
System: None, Unit: (None)
Item(Global): Unit Exponent, data= [ 0x0c ] 12
Unit Exponent: 12
Item(Global): Report Size, data= [ 0x10 ] 16
Item(Global): Report Count, data= [ 0x01 ] 1
Item(Local ): Usage, data= [ 0x03 ] 3
(null)
Item(Local ): String Index, data= [ 0x05 ] 5
Item(Main ): Input, data= [ 0xe2 0x01 ] 482
Data Variable Absolute No_Wrap Linear
No_Preferred_State Null_State Volatile Buffered Bytes
Item(Global): Logical Minimum, data= [ 0x00 ] 0
Item(Global): Logical Maximum, data= [ 0x64 0xd5 0x00 0x00 ] 54628
Item(Global): Physical Minimum, data= [ 0x00 ] 0
Item(Global): Physical Maximum, data= [ 0x64 0xd5 0x00 0x00 ] 54628
Item(Global): Unit, data= [ 0x01 0x00 0x01 0x00 ] 65537
System: SI Linear, Unit: Kelvin
Item(Global): Unit Exponent, data= [ 0x0e ] 14
Unit Exponent: 14
Item(Global): Report Size, data= [ 0x10 ] 16
Item(Global): Report Count, data= [ 0x01 ] 1
Item(Local ): Usage, data= [ 0x02 ] 2
Mouse
Item(Local ): String Index, data= [ 0x06 ] 6
Item(Main ): Input, data= [ 0xe2 0x01 ] 482
Data Variable Absolute No_Wrap Linear
No_Preferred_State Null_State Volatile Buffered Bytes
Item(Main ): End Collection, data=none
Item(Main ): End Collection, data=none
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 1
Device Status: 0x0000
(Bus Powered)
--
Sarah Mount, Senior Lecturer, University of Wolverhampton
Web: http://www.wlv.ac.uk/~in0316/
Book: http://www.pythonforrookies.org/
Blog: http://varspool.blogspot.com/
Photos: http://flickr.com/photos/sarahmount/
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