-
- Linux USB HID gadget driver
+===========================
+Linux USB HID gadget driver
+===========================
Introduction
+============
- The HID Gadget driver provides emulation of USB Human Interface
- Devices (HID). The basic HID handling is done in the kernel,
- and HID reports can be sent/received through I/O on the
- /dev/hidgX character devices.
+The HID Gadget driver provides emulation of USB Human Interface
+Devices (HID). The basic HID handling is done in the kernel,
+and HID reports can be sent/received through I/O on the
+/dev/hidgX character devices.
- For more details about HID, see the developer page on
- http://www.usb.org/developers/hidpage/
+For more details about HID, see the developer page on
+http://www.usb.org/developers/hidpage/
Configuration
+=============
- g_hid is a platform driver, so to use it you need to add
- struct platform_device(s) to your platform code defining the
- HID function descriptors you want to use - E.G. something
- like:
+g_hid is a platform driver, so to use it you need to add
+struct platform_device(s) to your platform code defining the
+HID function descriptors you want to use - E.G. something
+like::
-#include <linux/platform_device.h>
-#include <linux/usb/g_hid.h>
+ #include <linux/platform_device.h>
+ #include <linux/usb/g_hid.h>
-/* hid descriptor for a keyboard */
-static struct hidg_func_descriptor my_hid_data = {
+ /* hid descriptor for a keyboard */
+ static struct hidg_func_descriptor my_hid_data = {
.subclass = 0, /* No subclass */
.protocol = 1, /* Keyboard */
.report_length = 8,
0x81, 0x00, /* INPUT (Data,Ary,Abs) */
0xc0 /* END_COLLECTION */
}
-};
+ };
-static struct platform_device my_hid = {
+ static struct platform_device my_hid = {
.name = "hidg",
.id = 0,
.num_resources = 0,
.resource = 0,
.dev.platform_data = &my_hid_data,
-};
+ };
- You can add as many HID functions as you want, only limited by
- the amount of interrupt endpoints your gadget driver supports.
+You can add as many HID functions as you want, only limited by
+the amount of interrupt endpoints your gadget driver supports.
Configuration with configfs
+===========================
- Instead of adding fake platform devices and drivers in order to pass
- some data to the kernel, if HID is a part of a gadget composed with
- configfs the hidg_func_descriptor.report_desc is passed to the kernel
- by writing the appropriate stream of bytes to a configfs attribute.
+Instead of adding fake platform devices and drivers in order to pass
+some data to the kernel, if HID is a part of a gadget composed with
+configfs the hidg_func_descriptor.report_desc is passed to the kernel
+by writing the appropriate stream of bytes to a configfs attribute.
Send and receive HID reports
+============================
- HID reports can be sent/received using read/write on the
- /dev/hidgX character devices. See below for an example program
- to do this.
+HID reports can be sent/received using read/write on the
+/dev/hidgX character devices. See below for an example program
+to do this.
- hid_gadget_test is a small interactive program to test the HID
- gadget driver. To use, point it at a hidg device and set the
- device type (keyboard / mouse / joystick) - E.G.:
+hid_gadget_test is a small interactive program to test the HID
+gadget driver. To use, point it at a hidg device and set the
+device type (keyboard / mouse / joystick) - E.G.::
- # hid_gadget_test /dev/hidg0 keyboard
+ # hid_gadget_test /dev/hidg0 keyboard
- You are now in the prompt of hid_gadget_test. You can type any
- combination of options and values. Available options and
- values are listed at program start. In keyboard mode you can
- send up to six values.
+You are now in the prompt of hid_gadget_test. You can type any
+combination of options and values. Available options and
+values are listed at program start. In keyboard mode you can
+send up to six values.
- For example type: g i s t r --left-shift
+For example type: g i s t r --left-shift
- Hit return and the corresponding report will be sent by the
- HID gadget.
+Hit return and the corresponding report will be sent by the
+HID gadget.
- Another interesting example is the caps lock test. Type
- --caps-lock and hit return. A report is then sent by the
- gadget and you should receive the host answer, corresponding
- to the caps lock LED status.
+Another interesting example is the caps lock test. Type
+--caps-lock and hit return. A report is then sent by the
+gadget and you should receive the host answer, corresponding
+to the caps lock LED status::
- --caps-lock
- recv report:2
+ --caps-lock
+ recv report:2
- With this command:
+With this command::
- # hid_gadget_test /dev/hidg1 mouse
+ # hid_gadget_test /dev/hidg1 mouse
- You can test the mouse emulation. Values are two signed numbers.
+You can test the mouse emulation. Values are two signed numbers.
-Sample code
+Sample code::
-/* hid_gadget_test */
+ /* hid_gadget_test */
-#include <pthread.h>
-#include <string.h>
-#include <stdio.h>
-#include <ctype.h>
-#include <fcntl.h>
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
+ #include <string.h>
+ #include <stdio.h>
+ #include <ctype.h>
+ #include <fcntl.h>
+ #include <errno.h>
+ #include <stdio.h>
+ #include <stdlib.h>
+ #include <unistd.h>
-#define BUF_LEN 512
+ #define BUF_LEN 512
-struct options {
+ struct options {
const char *opt;
unsigned char val;
-};
+ };
-static struct options kmod[] = {
+ static struct options kmod[] = {
{.opt = "--left-ctrl", .val = 0x01},
{.opt = "--right-ctrl", .val = 0x10},
{.opt = "--left-shift", .val = 0x02},
{.opt = "--left-meta", .val = 0x08},
{.opt = "--right-meta", .val = 0x80},
{.opt = NULL}
-};
+ };
-static struct options kval[] = {
+ static struct options kval[] = {
{.opt = "--return", .val = 0x28},
{.opt = "--esc", .val = 0x29},
{.opt = "--bckspc", .val = 0x2a},
{.opt = "--up", .val = 0x52},
{.opt = "--num-lock", .val = 0x53},
{.opt = NULL}
-};
+ };
-int keyboard_fill_report(char report[8], char buf[BUF_LEN], int *hold)
-{
+ int keyboard_fill_report(char report[8], char buf[BUF_LEN], int *hold)
+ {
char *tok = strtok(buf, " ");
int key = 0;
int i = 0;
fprintf(stderr, "unknown option: %s\n", tok);
}
return 8;
-}
+ }
-static struct options mmod[] = {
+ static struct options mmod[] = {
{.opt = "--b1", .val = 0x01},
{.opt = "--b2", .val = 0x02},
{.opt = "--b3", .val = 0x04},
{.opt = NULL}
-};
+ };
-int mouse_fill_report(char report[8], char buf[BUF_LEN], int *hold)
-{
+ int mouse_fill_report(char report[8], char buf[BUF_LEN], int *hold)
+ {
char *tok = strtok(buf, " ");
int mvt = 0;
int i = 0;
fprintf(stderr, "unknown option: %s\n", tok);
}
return 3;
-}
+ }
-static struct options jmod[] = {
+ static struct options jmod[] = {
{.opt = "--b1", .val = 0x10},
{.opt = "--b2", .val = 0x20},
{.opt = "--b3", .val = 0x40},
{.opt = "--hat4", .val = 0x03},
{.opt = "--hatneutral", .val = 0x04},
{.opt = NULL}
-};
+ };
-int joystick_fill_report(char report[8], char buf[BUF_LEN], int *hold)
-{
+ int joystick_fill_report(char report[8], char buf[BUF_LEN], int *hold)
+ {
char *tok = strtok(buf, " ");
int mvt = 0;
int i = 0;
fprintf(stderr, "unknown option: %s\n", tok);
}
return 4;
-}
+ }
-void print_options(char c)
-{
+ void print_options(char c)
+ {
int i = 0;
if (c == 'k') {
" three signed numbers\n"
"--quit to close\n");
}
-}
+ }
-int main(int argc, const char *argv[])
-{
+ int main(int argc, const char *argv[])
+ {
const char *filename = NULL;
int fd = 0;
char buf[BUF_LEN];
close(fd);
return 0;
-}
+ }
git.samba.org / sfrench / cifs-2.6.git / blobdiff