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diff --git a/Documentation/hid/hidraw.txt b/Documentation/hid/hidraw.txt deleted file mode 100644 index c8436e354f44..000000000000 --- a/Documentation/hid/hidraw.txt +++ /dev/null @@ -1,119 +0,0 @@ - HIDRAW - Raw Access to USB and Bluetooth Human Interface Devices - ================================================================== - -The hidraw driver provides a raw interface to USB and Bluetooth Human -Interface Devices (HIDs). It differs from hiddev in that reports sent and -received are not parsed by the HID parser, but are sent to and received from -the device unmodified. - -Hidraw should be used if the userspace application knows exactly how to -communicate with the hardware device, and is able to construct the HID -reports manually. This is often the case when making userspace drivers for -custom HID devices. - -Hidraw is also useful for communicating with non-conformant HID devices -which send and receive data in a way that is inconsistent with their report -descriptors. Because hiddev parses reports which are sent and received -through it, checking them against the device's report descriptor, such -communication with these non-conformant devices is impossible using hiddev. -Hidraw is the only alternative, short of writing a custom kernel driver, for -these non-conformant devices. - -A benefit of hidraw is that its use by userspace applications is independent -of the underlying hardware type. Currently, Hidraw is implemented for USB -and Bluetooth. In the future, as new hardware bus types are developed which -use the HID specification, hidraw will be expanded to add support for these -new bus types. - -Hidraw uses a dynamic major number, meaning that udev should be relied on to -create hidraw device nodes. Udev will typically create the device nodes -directly under /dev (eg: /dev/hidraw0). As this location is distribution- -and udev rule-dependent, applications should use libudev to locate hidraw -devices attached to the system. There is a tutorial on libudev with a -working example at: - http://www.signal11.us/oss/udev/ - -The HIDRAW API ---------------- - -read() -------- -read() will read a queued report received from the HID device. On USB -devices, the reports read using read() are the reports sent from the device -on the INTERRUPT IN endpoint. By default, read() will block until there is -a report available to be read. read() can be made non-blocking, by passing -the O_NONBLOCK flag to open(), or by setting the O_NONBLOCK flag using -fcntl(). - -On a device which uses numbered reports, the first byte of the returned data -will be the report number; the report data follows, beginning in the second -byte. For devices which do not use numbered reports, the report data -will begin at the first byte. - -write() --------- -The write() function will write a report to the device. For USB devices, if -the device has an INTERRUPT OUT endpoint, the report will be sent on that -endpoint. If it does not, the report will be sent over the control endpoint, -using a SET_REPORT transfer. - -The first byte of the buffer passed to write() should be set to the report -number. If the device does not use numbered reports, the first byte should -be set to 0. The report data itself should begin at the second byte. - -ioctl() --------- -Hidraw supports the following ioctls: - -HIDIOCGRDESCSIZE: Get Report Descriptor Size -This ioctl will get the size of the device's report descriptor. - -HIDIOCGRDESC: Get Report Descriptor -This ioctl returns the device's report descriptor using a -hidraw_report_descriptor struct. Make sure to set the size field of the -hidraw_report_descriptor struct to the size returned from HIDIOCGRDESCSIZE. - -HIDIOCGRAWINFO: Get Raw Info -This ioctl will return a hidraw_devinfo struct containing the bus type, the -vendor ID (VID), and product ID (PID) of the device. The bus type can be one -of: - BUS_USB - BUS_HIL - BUS_BLUETOOTH - BUS_VIRTUAL -which are defined in uapi/linux/input.h. - -HIDIOCGRAWNAME(len): Get Raw Name -This ioctl returns a string containing the vendor and product strings of -the device. The returned string is Unicode, UTF-8 encoded. - -HIDIOCGRAWPHYS(len): Get Physical Address -This ioctl returns a string representing the physical address of the device. -For USB devices, the string contains the physical path to the device (the -USB controller, hubs, ports, etc). For Bluetooth devices, the string -contains the hardware (MAC) address of the device. - -HIDIOCSFEATURE(len): Send a Feature Report -This ioctl will send a feature report to the device. Per the HID -specification, feature reports are always sent using the control endpoint. -Set the first byte of the supplied buffer to the report number. For devices -which do not use numbered reports, set the first byte to 0. The report data -begins in the second byte. Make sure to set len accordingly, to one more -than the length of the report (to account for the report number). - -HIDIOCGFEATURE(len): Get a Feature Report -This ioctl will request a feature report from the device using the control -endpoint. The first byte of the supplied buffer should be set to the report -number of the requested report. For devices which do not use numbered -reports, set the first byte to 0. The report will be returned starting at -the first byte of the buffer (ie: the report number is not returned). - -Example ---------- -In samples/, find hid-example.c, which shows examples of read(), write(), -and all the ioctls for hidraw. The code may be used by anyone for any -purpose, and can serve as a starting point for developing applications using -hidraw. - -Document by: - Alan Ott <alan@signal11.us>, Signal 11 Software |