Summary of how to test HID function of USB gadget. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx> --- Documentation/usb/gadget-testing.txt | 47 ++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt index b7183e4..e7d29e5 100644 --- a/Documentation/usb/gadget-testing.txt +++ b/Documentation/usb/gadget-testing.txt @@ -6,6 +6,7 @@ provided by gadgets. 3. ECM subset function 4. EEM function 5. FFS function +6. HID function 1. ACM function @@ -158,3 +159,49 @@ Testing the FFS function On the device: start the function's userspace deamon, enable the gadget On the host: use the USB function provided by the device + +6. HID function +=============== + +The function is provided by usb_f_hid.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "hid". +The HID function provides these attributes in its function directory: + + protocol - HID protocol to use + report_desc - data to be used in HID reports, except data + passed with /dev/hidg<X> + report_length - HID report length + subclass - HID subclass to use + +For a keyboard the protocol and the subclass are 1, the report_length is 8, +while the report_desc is: + +$ hd my_report_desc +00000000 05 01 09 06 a1 01 05 07 19 e0 29 e7 15 00 25 01 |..........)...%.| +00000010 75 01 95 08 81 02 95 01 75 08 81 03 95 05 75 01 |u.......u.....u.| +00000020 05 08 19 01 29 05 91 02 95 01 75 03 91 03 95 06 |....).....u.....| +00000030 75 08 15 00 25 65 05 07 19 00 29 65 81 00 c0 |u...%e....)e...| +0000003f + +Such a sequence of bytes can be stored to the attribute with echo: + +$ echo -ne \\x05\\x01\\x09\\x06\\xa1..... + +Testing the HID function +------------------------ + +Device: +- create the gadget +- connect the gadget to a host, preferably not the one used +to control the gadget +- run a program which writes to /dev/hidg<N>, e.g. +a userspace program found in Documentation/usb/gadget_hid.txt: + +$ ./hid_gadget_test /dev/hidg0 keyboard + +Host: +- observe the keystrokes from the gadget -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
