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authorAndrzej Pietrasiewicz <andrzej.p@samsung.com>2014-12-16 13:56:30 (GMT)
committerFelipe Balbi <balbi@ti.com>2015-01-12 18:13:25 (GMT)
commitf7e3c3cd2401b3531a3ac4e279a08d03adb722e3 (patch)
treec9dc05ec5112bef230a35d085f52352051d08e05 /Documentation/usb
parent2c0f62f9e4f2c450342369dfd5858db51bc90fe3 (diff)
Documentation: usb: HID function testing
Summary of how to test HID function of USB gadget. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com> Signed-off-by: Felipe Balbi <balbi@ti.com>
Diffstat (limited to 'Documentation/usb')
-rw-r--r--Documentation/usb/gadget-testing.txt47
1 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt
index 141a1d0..f117e5c 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 daemon, 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

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