drivers/input/touchscreen/penmount.c

/*
 * Penmount serial touchscreen driver
 *
 * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com>
 * Copyright (c) 2011 John Sung <penmount.touch@gmail.com>
 *
 * Based on ELO driver (drivers/input/touchscreen/elo.c)
 * Copyright (c) 2004 Vojtech Pavlik
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/init.h>

#define DRIVER_DESC	"PenMount serial touchscreen driver"

MODULE_AUTHOR("Rick Koch <n1gp@hotmail.com>");
MODULE_AUTHOR("John Sung <penmount.touch@gmail.com>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
 * Definitions & global arrays.
 */

#define	PM_MAX_LENGTH	6

/*
 * Per-touchscreen data.
 */

struct pm {
	struct input_dev *dev;
	struct serio *serio;
	int idx;
	unsigned char data[PM_MAX_LENGTH];
	char phys[32];
	unsigned char packetsize;
};

/*
 * pm_checkpacket() checks if data packet is valid
 */

static bool pm_checkpacket(unsigned char *packet)
{
	int total = 0;
	int i;

	for (i = 0; i < 5; i++)
		total += packet[i];

	return packet[5] == (unsigned char)~(total & 0xff);
}

static irqreturn_t pm_interrupt(struct serio *serio,
		unsigned char data, unsigned int flags)
{
	struct pm *pm = serio_get_drvdata(serio);
	struct input_dev *dev = pm->dev;

	pm->data[pm->idx] = data;

	switch (pm->dev->id.product) {
	case 0x9000:
		if (pm->data[0] & 0x80) {
			if (pm->packetsize == ++pm->idx) {
				input_report_abs(dev, ABS_X, pm->data[1] * 128 + pm->data[2]);
				input_report_abs(dev, ABS_Y, pm->data[3] * 128 + pm->data[4]);
				input_report_key(dev, BTN_TOUCH, !!(pm->data[0] & 0x40));
				input_sync(dev);
				pm->idx = 0;
			}
		}
		break;

	case 0x6000:
		if ((pm->data[0] & 0xbf) == 0x30) {
			if (pm->packetsize == ++pm->idx) {
				if (pm_checkpacket(pm->data)) {
					input_report_abs(dev, ABS_X,
							pm->data[2] * 256 + pm->data[1]);
					input_report_abs(dev, ABS_Y,
							pm->data[4] * 256 + pm->data[3]);
					input_report_key(dev, BTN_TOUCH, !!(pm->data[0] & 0x40));
					input_sync(dev);
				}
				pm->idx = 0;
			}
		}
		break;
	}

	return IRQ_HANDLED;
}

/*
 * pm_disconnect() is the opposite of pm_connect()
 */

static void pm_disconnect(struct serio *serio)
{
	struct pm *pm = serio_get_drvdata(serio);

	input_get_device(pm->dev);
	input_unregister_device(pm->dev);
	serio_close(serio);
	serio_set_drvdata(serio, NULL);
	input_put_device(pm->dev);
	kfree(pm);
}

/*
 * pm_connect() is the routine that is called when someone adds a
 * new serio device that supports PenMount protocol and registers it as
 * an input device.
 */

static int pm_connect(struct serio *serio, struct serio_driver *drv)
{
	struct pm *pm;
	struct input_dev *input_dev;
	int err;

	pm = kzalloc(sizeof(struct pm), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!pm || !input_dev) {
		err = -ENOMEM;
		goto fail1;
	}

	pm->serio = serio;
	pm->dev = input_dev;
	snprintf(pm->phys, sizeof(pm->phys), "%s/input0", serio->phys);

	input_dev->name = "PenMount Serial TouchScreen";
	input_dev->phys = pm->phys;
	input_dev->id.bustype = BUS_RS232;
	input_dev->id.vendor = SERIO_PENMOUNT;
	input_dev->id.product = 0;
	input_dev->id.version = 0x0100;
	input_dev->dev.parent = &serio->dev;

        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
        input_set_abs_params(pm->dev, ABS_X, 0, 0x3ff, 0, 0);
        input_set_abs_params(pm->dev, ABS_Y, 0, 0x3ff, 0, 0);

	switch (serio->id.id) {
	default:
	case 0:
		pm->packetsize = 5;
		input_dev->id.product = 0x9000;
		break;

	case 1:
		pm->packetsize = 6;
		input_dev->id.product = 0x6000;
		break;
	}

	serio_set_drvdata(serio, pm);

	err = serio_open(serio, drv);
	if (err)
		goto fail2;

	err = input_register_device(pm->dev);
	if (err)
		goto fail3;

	return 0;

 fail3:	serio_close(serio);
 fail2:	serio_set_drvdata(serio, NULL);
 fail1:	input_free_device(input_dev);
	kfree(pm);
	return err;
}

/*
 * The serio driver structure.
 */

static struct serio_device_id pm_serio_ids[] = {
	{
		.type	= SERIO_RS232,
		.proto	= SERIO_PENMOUNT,
		.id	= SERIO_ANY,
		.extra	= SERIO_ANY,
	},
	{ 0 }
};

MODULE_DEVICE_TABLE(serio, pm_serio_ids);

static struct serio_driver pm_drv = {
	.driver		= {
		.name	= "serio-penmount",
	},
	.description	= DRIVER_DESC,
	.id_table	= pm_serio_ids,
	.interrupt	= pm_interrupt,
	.connect	= pm_connect,
	.disconnect	= pm_disconnect,
};

/*
 * The functions for inserting/removing us as a module.
 */

static int __init pm_init(void)
{
	return serio_register_driver(&pm_drv);
}

static void __exit pm_exit(void)
{
	serio_unregister_driver(&pm_drv);
}

module_init(pm_init);
module_exit(pm_exit);