mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
![Fabien Chouteau](/assets/img/avatar_default.png)
g_hid is a USB gadget driver implementing the Human Interface Device class specification. The driver handles basic HID protocol handling in the kernel, and allows userspace to read/write HID reports trough /dev/hidgX character devices. Signed-off-by: Fabien Chouteau <fabien.chouteau@barco.com> Signed-off-by: Peter Korsgaard <peter.korsgaard@barco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
445 lines
11 KiB
Text
445 lines
11 KiB
Text
|
||
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.
|
||
|
||
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:
|
||
|
||
#include <linux/platform_device.h>
|
||
#include <linux/usb/g_hid.h>
|
||
|
||
/* hid descriptor for a keyboard */
|
||
static struct hidg_func_descriptor my_hid_data = {
|
||
.subclass = 0, /* No subclass */
|
||
.protocol = 1, /* Keyboard */
|
||
.report_length = 8,
|
||
.report_desc_length = 63,
|
||
.report_desc = {
|
||
0x05, 0x01, /* USAGE_PAGE (Generic Desktop) */
|
||
0x09, 0x06, /* USAGE (Keyboard) */
|
||
0xa1, 0x01, /* COLLECTION (Application) */
|
||
0x05, 0x07, /* USAGE_PAGE (Keyboard) */
|
||
0x19, 0xe0, /* USAGE_MINIMUM (Keyboard LeftControl) */
|
||
0x29, 0xe7, /* USAGE_MAXIMUM (Keyboard Right GUI) */
|
||
0x15, 0x00, /* LOGICAL_MINIMUM (0) */
|
||
0x25, 0x01, /* LOGICAL_MAXIMUM (1) */
|
||
0x75, 0x01, /* REPORT_SIZE (1) */
|
||
0x95, 0x08, /* REPORT_COUNT (8) */
|
||
0x81, 0x02, /* INPUT (Data,Var,Abs) */
|
||
0x95, 0x01, /* REPORT_COUNT (1) */
|
||
0x75, 0x08, /* REPORT_SIZE (8) */
|
||
0x81, 0x03, /* INPUT (Cnst,Var,Abs) */
|
||
0x95, 0x05, /* REPORT_COUNT (5) */
|
||
0x75, 0x01, /* REPORT_SIZE (1) */
|
||
0x05, 0x08, /* USAGE_PAGE (LEDs) */
|
||
0x19, 0x01, /* USAGE_MINIMUM (Num Lock) */
|
||
0x29, 0x05, /* USAGE_MAXIMUM (Kana) */
|
||
0x91, 0x02, /* OUTPUT (Data,Var,Abs) */
|
||
0x95, 0x01, /* REPORT_COUNT (1) */
|
||
0x75, 0x03, /* REPORT_SIZE (3) */
|
||
0x91, 0x03, /* OUTPUT (Cnst,Var,Abs) */
|
||
0x95, 0x06, /* REPORT_COUNT (6) */
|
||
0x75, 0x08, /* REPORT_SIZE (8) */
|
||
0x15, 0x00, /* LOGICAL_MINIMUM (0) */
|
||
0x25, 0x65, /* LOGICAL_MAXIMUM (101) */
|
||
0x05, 0x07, /* USAGE_PAGE (Keyboard) */
|
||
0x19, 0x00, /* USAGE_MINIMUM (Reserved) */
|
||
0x29, 0x65, /* USAGE_MAXIMUM (Keyboard Application) */
|
||
0x81, 0x00, /* INPUT (Data,Ary,Abs) */
|
||
0xc0 /* END_COLLECTION */
|
||
}
|
||
};
|
||
|
||
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.
|
||
|
||
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_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
|
||
|
||
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
|
||
|
||
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.
|
||
|
||
--caps-lock
|
||
recv report:2
|
||
|
||
With this command:
|
||
|
||
# hid_gadget_test /dev/hidg1 mouse
|
||
|
||
You can test the mouse emulation. Values are two signed numbers.
|
||
|
||
|
||
Sample code
|
||
|
||
/* 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>
|
||
|
||
#define BUF_LEN 512
|
||
|
||
struct options {
|
||
const char *opt;
|
||
unsigned char val;
|
||
};
|
||
|
||
static struct options kmod[] = {
|
||
{.opt = "--left-ctrl", .val = 0x01},
|
||
{.opt = "--right-ctrl", .val = 0x10},
|
||
{.opt = "--left-shift", .val = 0x02},
|
||
{.opt = "--right-shift", .val = 0x20},
|
||
{.opt = "--left-alt", .val = 0x04},
|
||
{.opt = "--right-alt", .val = 0x40},
|
||
{.opt = "--left-meta", .val = 0x08},
|
||
{.opt = "--right-meta", .val = 0x80},
|
||
{.opt = NULL}
|
||
};
|
||
|
||
static struct options kval[] = {
|
||
{.opt = "--return", .val = 0x28},
|
||
{.opt = "--esc", .val = 0x29},
|
||
{.opt = "--bckspc", .val = 0x2a},
|
||
{.opt = "--tab", .val = 0x2b},
|
||
{.opt = "--spacebar", .val = 0x2c},
|
||
{.opt = "--caps-lock", .val = 0x39},
|
||
{.opt = "--f1", .val = 0x3a},
|
||
{.opt = "--f2", .val = 0x3b},
|
||
{.opt = "--f3", .val = 0x3c},
|
||
{.opt = "--f4", .val = 0x3d},
|
||
{.opt = "--f5", .val = 0x3e},
|
||
{.opt = "--f6", .val = 0x3f},
|
||
{.opt = "--f7", .val = 0x40},
|
||
{.opt = "--f8", .val = 0x41},
|
||
{.opt = "--f9", .val = 0x42},
|
||
{.opt = "--f10", .val = 0x43},
|
||
{.opt = "--f11", .val = 0x44},
|
||
{.opt = "--f12", .val = 0x45},
|
||
{.opt = "--insert", .val = 0x49},
|
||
{.opt = "--home", .val = 0x4a},
|
||
{.opt = "--pageup", .val = 0x4b},
|
||
{.opt = "--del", .val = 0x4c},
|
||
{.opt = "--end", .val = 0x4d},
|
||
{.opt = "--pagedown", .val = 0x4e},
|
||
{.opt = "--right", .val = 0x4f},
|
||
{.opt = "--left", .val = 0x50},
|
||
{.opt = "--down", .val = 0x51},
|
||
{.opt = "--kp-enter", .val = 0x58},
|
||
{.opt = "--up", .val = 0x52},
|
||
{.opt = "--num-lock", .val = 0x53},
|
||
{.opt = NULL}
|
||
};
|
||
|
||
int keyboard_fill_report(char report[8], char buf[BUF_LEN], int *hold)
|
||
{
|
||
char *tok = strtok(buf, " ");
|
||
int key = 0;
|
||
int i = 0;
|
||
|
||
for (; tok != NULL; tok = strtok(NULL, " ")) {
|
||
|
||
if (strcmp(tok, "--quit") == 0)
|
||
return -1;
|
||
|
||
if (strcmp(tok, "--hold") == 0) {
|
||
*hold = 1;
|
||
continue;
|
||
}
|
||
|
||
if (key < 6) {
|
||
for (i = 0; kval[i].opt != NULL; i++)
|
||
if (strcmp(tok, kval[i].opt) == 0) {
|
||
report[2 + key++] = kval[i].val;
|
||
break;
|
||
}
|
||
if (kval[i].opt != NULL)
|
||
continue;
|
||
}
|
||
|
||
if (key < 6)
|
||
if (islower(tok[0])) {
|
||
report[2 + key++] = (tok[0] - ('a' - 0x04));
|
||
continue;
|
||
}
|
||
|
||
for (i = 0; kmod[i].opt != NULL; i++)
|
||
if (strcmp(tok, kmod[i].opt) == 0) {
|
||
report[0] = report[0] | kmod[i].val;
|
||
break;
|
||
}
|
||
if (kmod[i].opt != NULL)
|
||
continue;
|
||
|
||
if (key < 6)
|
||
fprintf(stderr, "unknown option: %s\n", tok);
|
||
}
|
||
return 8;
|
||
}
|
||
|
||
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)
|
||
{
|
||
char *tok = strtok(buf, " ");
|
||
int mvt = 0;
|
||
int i = 0;
|
||
for (; tok != NULL; tok = strtok(NULL, " ")) {
|
||
|
||
if (strcmp(tok, "--quit") == 0)
|
||
return -1;
|
||
|
||
if (strcmp(tok, "--hold") == 0) {
|
||
*hold = 1;
|
||
continue;
|
||
}
|
||
|
||
for (i = 0; mmod[i].opt != NULL; i++)
|
||
if (strcmp(tok, mmod[i].opt) == 0) {
|
||
report[0] = report[0] | mmod[i].val;
|
||
break;
|
||
}
|
||
if (mmod[i].opt != NULL)
|
||
continue;
|
||
|
||
if (!(tok[0] == '-' && tok[1] == '-') && mvt < 2) {
|
||
errno = 0;
|
||
report[1 + mvt++] = (char)strtol(tok, NULL, 0);
|
||
if (errno != 0) {
|
||
fprintf(stderr, "Bad value:'%s'\n", tok);
|
||
report[1 + mvt--] = 0;
|
||
}
|
||
continue;
|
||
}
|
||
|
||
fprintf(stderr, "unknown option: %s\n", tok);
|
||
}
|
||
return 3;
|
||
}
|
||
|
||
static struct options jmod[] = {
|
||
{.opt = "--b1", .val = 0x10},
|
||
{.opt = "--b2", .val = 0x20},
|
||
{.opt = "--b3", .val = 0x40},
|
||
{.opt = "--b4", .val = 0x80},
|
||
{.opt = "--hat1", .val = 0x00},
|
||
{.opt = "--hat2", .val = 0x01},
|
||
{.opt = "--hat3", .val = 0x02},
|
||
{.opt = "--hat4", .val = 0x03},
|
||
{.opt = "--hatneutral", .val = 0x04},
|
||
{.opt = NULL}
|
||
};
|
||
|
||
int joystick_fill_report(char report[8], char buf[BUF_LEN], int *hold)
|
||
{
|
||
char *tok = strtok(buf, " ");
|
||
int mvt = 0;
|
||
int i = 0;
|
||
|
||
*hold = 1;
|
||
|
||
/* set default hat position: neutral */
|
||
report[3] = 0x04;
|
||
|
||
for (; tok != NULL; tok = strtok(NULL, " ")) {
|
||
|
||
if (strcmp(tok, "--quit") == 0)
|
||
return -1;
|
||
|
||
for (i = 0; jmod[i].opt != NULL; i++)
|
||
if (strcmp(tok, jmod[i].opt) == 0) {
|
||
report[3] = (report[3] & 0xF0) | jmod[i].val;
|
||
break;
|
||
}
|
||
if (jmod[i].opt != NULL)
|
||
continue;
|
||
|
||
if (!(tok[0] == '-' && tok[1] == '-') && mvt < 3) {
|
||
errno = 0;
|
||
report[mvt++] = (char)strtol(tok, NULL, 0);
|
||
if (errno != 0) {
|
||
fprintf(stderr, "Bad value:'%s'\n", tok);
|
||
report[mvt--] = 0;
|
||
}
|
||
continue;
|
||
}
|
||
|
||
fprintf(stderr, "unknown option: %s\n", tok);
|
||
}
|
||
return 4;
|
||
}
|
||
|
||
void print_options(char c)
|
||
{
|
||
int i = 0;
|
||
|
||
if (c == 'k') {
|
||
printf(" keyboard options:\n"
|
||
" --hold\n");
|
||
for (i = 0; kmod[i].opt != NULL; i++)
|
||
printf("\t\t%s\n", kmod[i].opt);
|
||
printf("\n keyboard values:\n"
|
||
" [a-z] or\n");
|
||
for (i = 0; kval[i].opt != NULL; i++)
|
||
printf("\t\t%-8s%s", kval[i].opt, i % 2 ? "\n" : "");
|
||
printf("\n");
|
||
} else if (c == 'm') {
|
||
printf(" mouse options:\n"
|
||
" --hold\n");
|
||
for (i = 0; mmod[i].opt != NULL; i++)
|
||
printf("\t\t%s\n", mmod[i].opt);
|
||
printf("\n mouse values:\n"
|
||
" Two signed numbers\n"
|
||
"--quit to close\n");
|
||
} else {
|
||
printf(" joystick options:\n");
|
||
for (i = 0; jmod[i].opt != NULL; i++)
|
||
printf("\t\t%s\n", jmod[i].opt);
|
||
printf("\n joystick values:\n"
|
||
" three signed numbers\n"
|
||
"--quit to close\n");
|
||
}
|
||
}
|
||
|
||
int main(int argc, const char *argv[])
|
||
{
|
||
const char *filename = NULL;
|
||
int fd = 0;
|
||
char buf[BUF_LEN];
|
||
int cmd_len;
|
||
char report[8];
|
||
int to_send = 8;
|
||
int hold = 0;
|
||
fd_set rfds;
|
||
int retval, i;
|
||
|
||
if (argc < 3) {
|
||
fprintf(stderr, "Usage: %s devname mouse|keyboard|joystick\n",
|
||
argv[0]);
|
||
return 1;
|
||
}
|
||
|
||
if (argv[2][0] != 'k' && argv[2][0] != 'm' && argv[2][0] != 'j')
|
||
return 2;
|
||
|
||
filename = argv[1];
|
||
|
||
if ((fd = open(filename, O_RDWR, 0666)) == -1) {
|
||
perror(filename);
|
||
return 3;
|
||
}
|
||
|
||
print_options(argv[2][0]);
|
||
|
||
while (42) {
|
||
|
||
FD_ZERO(&rfds);
|
||
FD_SET(STDIN_FILENO, &rfds);
|
||
FD_SET(fd, &rfds);
|
||
|
||
retval = select(fd + 1, &rfds, NULL, NULL, NULL);
|
||
if (retval == -1 && errno == EINTR)
|
||
continue;
|
||
if (retval < 0) {
|
||
perror("select()");
|
||
return 4;
|
||
}
|
||
|
||
if (FD_ISSET(fd, &rfds)) {
|
||
cmd_len = read(fd, buf, BUF_LEN - 1);
|
||
printf("recv report:");
|
||
for (i = 0; i < cmd_len; i++)
|
||
printf(" %02x", buf[i]);
|
||
printf("\n");
|
||
}
|
||
|
||
if (FD_ISSET(STDIN_FILENO, &rfds)) {
|
||
memset(report, 0x0, sizeof(report));
|
||
cmd_len = read(STDIN_FILENO, buf, BUF_LEN - 1);
|
||
|
||
if (cmd_len == 0)
|
||
break;
|
||
|
||
buf[cmd_len - 1] = '\0';
|
||
hold = 0;
|
||
|
||
memset(report, 0x0, sizeof(report));
|
||
if (argv[2][0] == 'k')
|
||
to_send = keyboard_fill_report(report, buf, &hold);
|
||
else if (argv[2][0] == 'm')
|
||
to_send = mouse_fill_report(report, buf, &hold);
|
||
else
|
||
to_send = joystick_fill_report(report, buf, &hold);
|
||
|
||
if (to_send == -1)
|
||
break;
|
||
|
||
if (write(fd, report, to_send) != to_send) {
|
||
perror(filename);
|
||
return 5;
|
||
}
|
||
if (!hold) {
|
||
memset(report, 0x0, sizeof(report));
|
||
if (write(fd, report, to_send) != to_send) {
|
||
perror(filename);
|
||
return 6;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
close(fd);
|
||
return 0;
|
||
}
|