USB: gadget: add HID gadget driver

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>

1 files changed, 445 insertions, 0 deletions

diff --git a/Documentation/usb/gadget_hid.txt b/Documentation/usb/gadget_hid.txt
new file mode 100644
index 000000000000..f4a51f567427
--- /dev/null
+++ b/Documentation/usb/gadget_hid.txt
@@ -0,0 +1,445 @@
+
+                     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;
+}