// SPDX-License-Identifier: GPL-2.0-only/* * Sahara TouchIT-213 serial touchscreen driver * * Copyright (c) 2007-2008 Claudio Nieder <private@claudio.ch> * * Based on Touchright driver (drivers/input/touchscreen/touchright.c) * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com> * Copyright (c) 2004 Vojtech Pavlik * and Dan Streetman <ddstreet@ieee.org> */  #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	"Sahara TouchIT-213 serial touchscreen driver" MODULE_AUTHOR("Claudio Nieder <private@claudio.ch>");MODULE_DESCRIPTION(DRIVER_DESC);MODULE_LICENSE("GPL"); /* * 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	0x01#define T213_FORMAT_STATUS_BYTE	0x80#define T213_FORMAT_STATUS_MASK	~T213_FORMAT_TOUCH_BIT /* * 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 0#define T213_MAX_XC 0x07ff#define T213_MIN_YC 0#define T213_MAX_YC 0x07ff /* * Per-touchscreen data. */ struct touchit213 {	struct input_dev *dev;	struct serio *serio;	int idx;	unsigned char csum;	unsigned char data[5];	char phys[32];}; static irqreturn_t touchit213_interrupt(struct serio *serio,		unsigned char data, unsigned int flags){	struct touchit213 *touchit213 = serio_get_drvdata(serio);	struct input_dev *dev = touchit213->dev; 	touchit213->data[touchit213->idx] = data; 	switch (touchit213->idx++) {	case 0:		if ((touchit213->data[0] & T213_FORMAT_STATUS_MASK) !=				T213_FORMAT_STATUS_BYTE) {			pr_debug("unsynchronized data: 0x%02x\n", data);			touchit213->idx = 0;		}		break; 	case 4:		touchit213->idx = 0;		input_report_abs(dev, ABS_X,			(touchit213->data[1] << 7) | touchit213->data[2]);		input_report_abs(dev, ABS_Y,			(touchit213->data[3] << 7) | touchit213->data[4]);		input_report_key(dev, BTN_TOUCH,			touchit213->data[0] & T213_FORMAT_TOUCH_BIT);		input_sync(dev);		break;	} 	return IRQ_HANDLED;} /* * touchit213_disconnect() is the opposite of touchit213_connect() */ static void touchit213_disconnect(struct serio *serio){	struct touchit213 *touchit213 = serio_get_drvdata(serio); 	input_get_device(touchit213->dev);	input_unregister_device(touchit213->dev);	serio_close(serio);	serio_set_drvdata(serio, NULL);	input_put_device(touchit213->dev);	kfree(touchit213);} /* * 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){	struct touchit213 *touchit213;	struct input_dev *input_dev;	int err; 	touchit213 = kzalloc_obj(*touchit213);	input_dev = input_allocate_device();	if (!touchit213 || !input_dev) {		err = -ENOMEM;		goto fail1;	} 	touchit213->serio = serio;	touchit213->dev = input_dev;	scnprintf(touchit213->phys, sizeof(touchit213->phys),		  "%s/input0", serio->phys); 	input_dev->name = "Sahara Touch-iT213 Serial TouchScreen";	input_dev->phys = touchit213->phys;	input_dev->id.bustype = BUS_RS232;	input_dev->id.vendor = SERIO_TOUCHIT213;	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(touchit213->dev, ABS_X,			     T213_MIN_XC, T213_MAX_XC, 0, 0);	input_set_abs_params(touchit213->dev, ABS_Y,			     T213_MIN_YC, T213_MAX_YC, 0, 0); 	serio_set_drvdata(serio, touchit213); 	err = serio_open(serio, drv);	if (err)		goto fail2; 	err = input_register_device(touchit213->dev);	if (err)		goto fail3; 	return 0;  fail3:	serio_close(serio); fail2:	serio_set_drvdata(serio, NULL); fail1:	input_free_device(input_dev);	kfree(touchit213);	return err;} /* * The serio driver structure. */ static const struct serio_device_id touchit213_serio_ids[] = {	{		.type	= SERIO_RS232,		.proto	= SERIO_TOUCHIT213,		.id	= SERIO_ANY,		.extra	= SERIO_ANY,	},	{ 0 }}; MODULE_DEVICE_TABLE(serio, touchit213_serio_ids); static struct serio_driver touchit213_drv = {	.driver		= {		.name	= "touchit213",	},	.description	= DRIVER_DESC,	.id_table	= touchit213_serio_ids,	.interrupt	= touchit213_interrupt,	.connect	= touchit213_connect,	.disconnect	= touchit213_disconnect,}; module_serio_driver(touchit213_drv);