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;
+}