linux/drivers/input/touchscreen/touchit213.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Sahara TouchIT-213 serial touchscreen driver
 *
 * Copyright (c) 2007-2008 Claudio Nieder <[email protected]>
 *
 * Based on Touchright driver (drivers/input/touchscreen/touchright.c)
 * Copyright (c) 2006 Rick Koch <[email protected]>
 * Copyright (c) 2004 Vojtech Pavlik
 * and Dan Streetman <[email protected]>
 */


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

#define DRIVER_DESC …

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…);
MODULE_LICENSE(…) …;

/*
 * Definitions & global arrays.
 */

/*
 * Data is received through COM1 at 9600bit/s,8bit,no parity in packets
 * of 5 byte each.
 *
 *   +--------+   +--------+   +--------+   +--------+   +--------+
 *   |1000000p|   |0xxxxxxx|   |0xxxxxxx|   |0yyyyyyy|   |0yyyyyyy|
 *   +--------+   +--------+   +--------+   +--------+   +--------+
 *                    MSB          LSB          MSB          LSB
 *
 * The value of p is 1 as long as the screen is touched and 0 when
 * reporting the location where touching stopped, e.g. where the pen was
 * lifted from the screen.
 *
 * When holding the screen in landscape mode as the BIOS text output is
 * presented, x is the horizontal axis with values growing from left to
 * right and y is the vertical axis with values growing from top to
 * bottom.
 *
 * When holding the screen in portrait mode with the Sahara logo in its
 * correct position, x ist the vertical axis with values growing from
 * top to bottom and y is the horizontal axis with values growing from
 * right to left.
 */

#define T213_FORMAT_TOUCH_BIT …
#define T213_FORMAT_STATUS_BYTE …
#define T213_FORMAT_STATUS_MASK …

/*
 * On my Sahara Touch-IT 213 I have observed x values from 0 to 0x7f0
 * and y values from 0x1d to 0x7e9, so the actual measurement is
 * probably done with an 11 bit precision.
 */
#define T213_MIN_XC …
#define T213_MAX_XC …
#define T213_MIN_YC …
#define T213_MAX_YC …

/*
 * Per-touchscreen data.
 */

struct touchit213 { … };

static irqreturn_t touchit213_interrupt(struct serio *serio,
		unsigned char data, unsigned int flags)
{ … }

/*
 * touchit213_disconnect() is the opposite of touchit213_connect()
 */

static void touchit213_disconnect(struct serio *serio)
{ … }

/*
 * touchit213_connect() is the routine that is called when someone adds a
 * new serio device that supports the Touchright protocol and registers it as
 * an input device.
 */

static int touchit213_connect(struct serio *serio, struct serio_driver *drv)
{ … }

/*
 * The serio driver structure.
 */

static const struct serio_device_id touchit213_serio_ids[] = …;

MODULE_DEVICE_TABLE(serio, touchit213_serio_ids);

static struct serio_driver touchit213_drv = …;

module_serio_driver(…) …;