The uhid driver provides support for all HID (Human Interface Device) interfaces in USB devices that do
not have a special driver.
The device handles the following ioctl(2) calls:
USB_GET_REPORT_ID (int)
Get the report identifier used by this HID report.
USB_GET_REPORT_DESC (structusb_gen_descriptor)
Get the HID report descriptor. Copies a maximum of ugd_maxlen bytes of the report descriptor
data into the memory specified by ugd_data. Upon return ugd_actlen is set to the number of bytes
copied. Using this descriptor the exact layout and meaning of data to/from the device can be
found. The report descriptor is delivered without any processing.
struct usb_gen_descriptor {
void *ugd_data;
uint16_t ugd_maxlen;
uint16_t ugd_actlen;
uint8_t ugd_report_type;
...
};
USB_SET_IMMED (int)
Sets the device in a mode where each read(2) will return the current value of the input report.
Normally a read(2) will only return the data that the device reports on its interrupt pipe. This
call may fail if the device does not support this feature.
USB_GET_REPORT (structusb_gen_descriptor)
Get a report from the device without waiting for data on the interrupt pipe. Copies a maximum of
ugd_maxlen bytes of the report data into the memory specified by ugd_data. Upon return
ugd_actlen is set to the number of bytes copied. The ugd_report_type field indicates which
report is requested. It should be UHID_INPUT_REPORT, UHID_OUTPUT_REPORT, or UHID_FEATURE_REPORT.
This call may fail if the device does not support this feature.
USB_SET_REPORT (structusb_gen_descriptor)
Set a report in the device. The ugd_report_type field indicates which report is to be set. It
should be UHID_INPUT_REPORT, UHID_OUTPUT_REPORT, or UHID_FEATURE_REPORT. The value of the report
is specified by the ugd_data and the ugd_maxlen fields. This call may fail if the device does
not support this feature.
Use read(2) to get data from the device. Data should be read in chunks of the size prescribed by the
report descriptor.
Use write(2) to send data to the device. Data should be written in chunks of the size prescribed by the
report descriptor.