// SPDX-License-Identifier: GPL-2.0-only/* * Touchwindow serial touchscreen driver * * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com> * * Based on MicroTouch driver (drivers/input/touchscreen/mtouch.c) * Copyright (c) 2004 Vojtech Pavlik * and Dan Streetman <ddstreet@ieee.org> */  /* * 2005/02/19 Rick Koch: *   The Touchwindow I used is made by Edmark Corp. and *   constantly outputs a stream of 0's unless it is touched. *   It then outputs 3 bytes: X, Y, and a copy of Y. */ #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	"Touchwindow serial touchscreen driver" MODULE_AUTHOR("Rick Koch <n1gp@hotmail.com>");MODULE_DESCRIPTION(DRIVER_DESC);MODULE_LICENSE("GPL"); /* * Definitions & global arrays. */ #define TW_LENGTH 3 #define TW_MIN_XC 0#define TW_MAX_XC 0xff#define TW_MIN_YC 0#define TW_MAX_YC 0xff /* * Per-touchscreen data. */ struct tw {	struct input_dev *dev;	struct serio *serio;	int idx;	int touched;	unsigned char data[TW_LENGTH];	char phys[32];}; static irqreturn_t tw_interrupt(struct serio *serio,		unsigned char data, unsigned int flags){	struct tw *tw = serio_get_drvdata(serio);	struct input_dev *dev = tw->dev; 	if (data) {		/* touch */		tw->touched = 1;		tw->data[tw->idx++] = data;		/* verify length and that the two Y's are the same */		if (tw->idx == TW_LENGTH && tw->data[1] == tw->data[2]) {			input_report_abs(dev, ABS_X, tw->data[0]);			input_report_abs(dev, ABS_Y, tw->data[1]);			input_report_key(dev, BTN_TOUCH, 1);			input_sync(dev);			tw->idx = 0;		}	} else if (tw->touched) {	/* untouch */		input_report_key(dev, BTN_TOUCH, 0);		input_sync(dev);		tw->idx = 0;		tw->touched = 0;	} 	return IRQ_HANDLED;} /* * tw_disconnect() is the opposite of tw_connect() */ static void tw_disconnect(struct serio *serio){	struct tw *tw = serio_get_drvdata(serio); 	input_get_device(tw->dev);	input_unregister_device(tw->dev);	serio_close(serio);	serio_set_drvdata(serio, NULL);	input_put_device(tw->dev);	kfree(tw);} /* * tw_connect() is the routine that is called when someone adds a * new serio device that supports the Touchwin protocol and registers it as * an input device. */ static int tw_connect(struct serio *serio, struct serio_driver *drv){	struct tw *tw;	struct input_dev *input_dev;	int err; 	tw = kzalloc(sizeof(struct tw), GFP_KERNEL);	input_dev = input_allocate_device();	if (!tw || !input_dev) {		err = -ENOMEM;		goto fail1;	} 	tw->serio = serio;	tw->dev = input_dev;	snprintf(tw->phys, sizeof(tw->phys), "%s/input0", serio->phys); 	input_dev->name = "Touchwindow Serial TouchScreen";	input_dev->phys = tw->phys;	input_dev->id.bustype = BUS_RS232;	input_dev->id.vendor = SERIO_TOUCHWIN;	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(tw->dev, ABS_X, TW_MIN_XC, TW_MAX_XC, 0, 0);	input_set_abs_params(tw->dev, ABS_Y, TW_MIN_YC, TW_MAX_YC, 0, 0); 	serio_set_drvdata(serio, tw); 	err = serio_open(serio, drv);	if (err)		goto fail2; 	err = input_register_device(tw->dev);	if (err)		goto fail3; 	return 0;  fail3:	serio_close(serio); fail2:	serio_set_drvdata(serio, NULL); fail1:	input_free_device(input_dev);	kfree(tw);	return err;} /* * The serio driver structure. */ static const struct serio_device_id tw_serio_ids[] = {	{		.type	= SERIO_RS232,		.proto	= SERIO_TOUCHWIN,		.id	= SERIO_ANY,		.extra	= SERIO_ANY,	},	{ 0 }}; MODULE_DEVICE_TABLE(serio, tw_serio_ids); static struct serio_driver tw_drv = {	.driver		= {		.name	= "touchwin",	},	.description	= DRIVER_DESC,	.id_table	= tw_serio_ids,	.interrupt	= tw_interrupt,	.connect	= tw_connect,	.disconnect	= tw_disconnect,}; module_serio_driver(tw_drv);