Linux下HID 设备

struct HIDIOCGREPORTINFO hiddev_report_info (read/write)
with a report in a hiddev_field_info structure. The user must struct hiddev_field_info fill in report_id and HIDIOCGFIELDINFO report_type in this (read/write) structure, as above. The field_index should also be filled in, which should be a number from 0 and maxfield-1, as returned from a previous HIDIOCGREPORTINFO call. Returns the usage_code in a hiddev_usage_ref structure, given that given its report type, struct hiddev_usage_ref HIDIOCGUCODE report id, field index, (read/write) and index within the field have already been filled into the structure. Returns the value of a usage in a hiddev_usage_ref structure. The usage to be retrieved can be specified as above, or the user can choose to fill in the report_type struct hiddev_usage_ref field and specify the HIDIOCGUSAGE (read/write) report_id asHID_REPORT_ID_UNKNOWN. In this case, the hiddev_usage_ref will be filled in with the report and field infomation associated with this usage if it is found.
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HIDIOCSREPORT
struct hiddev_report_info (write)
throughHIDIOCSUSAGE calls (below) to fill in individual usage values in the report before sending the report in full to the device. Fills in a hiddev_report_info structure for the user. The report is looked up by type (input, output or feature) and id, so these fields must be filled in by the user. The ID can be absolute - the actual report id as reported by the device -- or relative -HID_REPORT_ID_FIRST for the first report, and (HID_REPORT_ID_NEXT | report_id) for the next report after report_id. Without a-priori information about report ids, the right way to use this ioctl is to use the relative IDs above to enumerate the valid IDs. The ioctl returns non-zero when there is no more next ID. The real report ID is filled into the returned hiddev_report_info structure. Returns the field information associated
HIDIOCGVERSION int (read) Gets the version code out of the hiddev driver. This ioctl call returns the HID application usage associated with the hid device. The third argument to ioctl() specifies which application index to get. This is useful when the device has more than one application collection. If the index is invalid (greater or equal to the number of application collections this device has) the ioctl returns -1. You
对此设备结点的处理有两种接口，一种是read(),另一种是ioctl()；
read(): This is the event interface. When the HID device performs an interrupt transfer, indicating a change of state, data will be made available at the associated hiddev device with the content of a struct hiddev_event:struct hiddev_event { unsigned hid; signed int value; }; containing the HID usage identifier for the status that changed, and the value that it was changed to. ioctl(): This is the control interface. There are a number of controls:
HIDIOCAPPLICATION(none)
can find out beforehand how many application collections the device has from the num_applications field from the hiddev_devinfo structure. Gets a hiddev_devinfo struct hiddev_devinfo HIDIOCGDEVINFO structure which (read) describes the device. Gets a string descriptor from the device. The struct struct caller must fill in the HIDIOCGSTRING hiddev_string_descriptor "index" field to (read/write) indicate which descriptor should be returned. Instructs the kernel to retrieve all input and feature report values from the device. At this point, all the usage HIDIOCINITREPORT structures will contain current values for the device, and will maintain it as the device changes. HIDIOCGNAME string (variable length)Gets the device name Instructs the kernel to get a feature or input struct report from the device, HIDIOCGREPORT hiddev_report_info in order to selectively (write) update the usage structures (in contrast to INITREPORT). Instructs the kernel to send a report to the device. This report can be filled in by the user
HIDIOCSUSAGE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
struct hiddev_usage_ref Sets the value of a usage in an output (write) report.
Linux下HID 设备，如果非标准的输入设备 （Keypad/MOUSE/JoyStick/input event device). 将会把信息转入hid device的设备结点。 这一点可以参见内核的关于hiddev的文档 /source/Documentation/usb/hiddev.txt?v=2.6.30 它在 Documentation/usb/hiddev.txt 目录下，大致有这样一个流程， usb.c ---> hid-core.c ----> hid-input.c ----> [keyboard/mouse/joystick/event] | | --> hiddev.c ----> POWER / MONITOR CONTROL 关于操作非标准的HID设备，可以参见如下文档. /hiddev/ 在设备文件系统中，会产生的/dev/hiddev0这样的结点，这类设备主设 备号为 180,从设备号最低为96 Cat /proc/device | grep hiddev mknod /dev/hiddev0 c 180 96 mknod /dev/hiddev1 c 180 97 mknod /dev/hiddev2 c 180 98 mknod /dev/hiddev3 c 180 99 ... mknod /dev/hiddev15 c 180 111