Touchscreen USB HID gadget

[Constantine Shulyupin]

Once up on a time I've  emulated a usb touchscreen using USB HID
gadget driver. I captured and configured report descriptor and wrote
sample application to just move cursor. Sources are attached.

-- 
Constantine Shulyupin
http://www.MakeLinux.com/
Embedded Linux Systems,
Device Drivers, TI DaVinci

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/usb/g_hid.h>
#include <linux/hid.h>

static struct hidg_func_descriptor hidg_touchscreen_dev_data = {
	.subclass		= 0, /* No subclass */
	.protocol		= USB_INTERFACE_PROTOCOL_MOUSE,
	.report_length		= 64,
	.report_desc_length	= 249,
	.report_desc		= {
    0x06, 0xff, 0xff, 0x09, 0xff, 0xa1, 0x01, 0x85, 0x01, 0x09, 0xff, 0x15, 0x80, 0x25, 0x7f, 0x75,
    0x08, 0x95, 0x20, 0x81, 0x00, 0x85, 0x02, 0x09, 0xff, 0x91, 0x00, 0xc0, 0x05, 0x0d, 0x09, 0x04,
    0xa1, 0x01, 0x85, 0x04, 0x09, 0x22, 0xa1, 0x02, 0x09, 0x42, 0x15, 0x00, 0x25, 0x01, 0x75, 0x01,
    0x95, 0x01, 0x81, 0x02, 0x09, 0x32, 0x81, 0x02, 0x09, 0x47, 0x81, 0x02, 0x95, 0x05, 0x81, 0x03,
    0x75, 0x08, 0x09, 0x51, 0x95, 0x01, 0x81, 0x02, 0x05, 0x01, 0x26, 0xff, 0x7f, 0x75, 0x10, 0x55,
    0x00, 0x65, 0x00, 0x09, 0x30, 0x35, 0x00, 0x46, 0x00, 0x00, 0x81, 0x02, 0x09, 0x31, 0x26, 0xff,
    0x7f, 0x46, 0x00, 0x00, 0x81, 0x02, 0xc0, 0xa1, 0x02, 0x05, 0x0d, 0x09, 0x42, 0x15, 0x00, 0x25,
    0x01, 0x75, 0x01, 0x95, 0x01, 0x81, 0x02, 0x09, 0x32, 0x81, 0x02, 0x09, 0x47, 0x81, 0x02, 0x95,
    0x05, 0x81, 0x03, 0x75, 0x08, 0x09, 0x51, 0x95, 0x01, 0x81, 0x02, 0x05, 0x01, 0x26, 0xff, 0x7f,
    0x75, 0x10, 0x55, 0x00, 0x65, 0x00, 0x09, 0x30, 0x35, 0x00, 0x46, 0x00, 0x00, 0x81, 0x02, 0x09,
    0x31, 0x26, 0xff, 0x7f, 0x46, 0x00, 0x00, 0x81, 0x02, 0xc0, 0x05, 0x0d, 0x09, 0x54, 0x95, 0x01,
    0x75, 0x08, 0x15, 0x00, 0x25, 0x08, 0x81, 0x02, 0x09, 0x55, 0xb1, 0x02, 0xc0, 0x05, 0x01, 0x09,
    0x02, 0xa1, 0x01, 0x85, 0x05, 0x09, 0x01, 0xa1, 0x00, 0x05, 0x09, 0x19, 0x01, 0x29, 0x03, 0x15,
    0x00, 0x25, 0x01, 0x95, 0x03, 0x75, 0x01, 0x81, 0x02, 0x95, 0x01, 0x75, 0x05, 0x81, 0x01, 0x05,
    0x01, 0x09, 0x30, 0x15, 0x00, 0x26, 0xff, 0x7f, 0x35, 0x00, 0x46, 0xff, 0x7f, 0x75, 0x10, 0x95,
    0x01, 0x81, 0x02, 0x09, 0x31, 0x81, 0x02, 0xc0, 0xc0,
	}
};

static struct platform_device hidg_pdev = {
	.name			= "hidg",
	.dev.platform_data	= &hidg_touchscreen_dev_data,
};

static int __init hidg_pdev_init(void)
{
	return platform_device_register(&hidg_pdev);
}
module_init(hidg_pdev_init);

static void __exit hidg_pdev_cleanup(void)
{
	platform_device_unregister(&hidg_pdev);
}
module_exit(hidg_pdev_cleanup);

MODULE_LICENSE("GPL");

#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 <arpa/inet.h>
#define BUF_LEN 512

int main(int argc, const char *argv[])
{
	int fd = 0;
	char buf[BUF_LEN];
	int cmd_len;
	struct report {
		short a;
		short b;
		unsigned xyz;
	} report;
	int to_send;
	int hold = 1;
	fd_set rfds;
	int retval, i;

	if ((fd = open("/dev/hidg0", O_RDWR, 0666)) == -1) {
		perror("open");
		return -1;
	}
	report.xyz = htonl(0x12345678);
	write(fd, &report, sizeof(report));	// conversion test
	for (i = 0x1000; i < 0x6000; i += 0x1111) {
		// finger move
		memset(&report, 0x0, sizeof(report));
		report.a = htons(0x0407);
		report.b = htons(0x0110);
		report.xyz = htonl((i << 16) | (i << 4) | 7);

		to_send = sizeof(report);
		sleep(1);
		write(fd, &report, sizeof(report));
	}
	{			// finger up
		memset(&report, 0x0, sizeof(report));
		report.a = htons(0x0400);
		write(fd, &report, sizeof(report));
	}
	close(fd);
}

Makefile
Description: Binary data