// SPDX-License-Identifier: GPL-2.0-only/* * Fujitsu serial touchscreen driver * * Copyright (c) Dmitry Torokhov <dtor@mail.ru> */  #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	"Fujitsu serial touchscreen driver" MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");MODULE_DESCRIPTION(DRIVER_DESC);MODULE_LICENSE("GPL"); #define FUJITSU_LENGTH 5 /* * Per-touchscreen data. */struct fujitsu {	struct input_dev *dev;	struct serio *serio;	int idx;	unsigned char data[FUJITSU_LENGTH];	char phys[32];}; /* * Decode serial data (5 bytes per packet) * First byte * 1 C 0 0 R S S S * Where C is 1 while in calibration mode (which we don't use) * R is 1 when no coordinate corection was done. * S are button state */static irqreturn_t fujitsu_interrupt(struct serio *serio,				     unsigned char data, unsigned int flags){	struct fujitsu *fujitsu = serio_get_drvdata(serio);	struct input_dev *dev = fujitsu->dev; 	if (fujitsu->idx == 0) {		/* resync skip until start of frame */		if ((data & 0xf0) != 0x80)			return IRQ_HANDLED;	} else {		/* resync skip garbage */		if (data & 0x80) {			fujitsu->idx = 0;			return IRQ_HANDLED;		}	} 	fujitsu->data[fujitsu->idx++] = data;	if (fujitsu->idx == FUJITSU_LENGTH) {		input_report_abs(dev, ABS_X,				 (fujitsu->data[2] << 7) | fujitsu->data[1]);		input_report_abs(dev, ABS_Y,				 (fujitsu->data[4] << 7) | fujitsu->data[3]);		input_report_key(dev, BTN_TOUCH,				 (fujitsu->data[0] & 0x03) != 2);		input_sync(dev);		fujitsu->idx = 0;	} 	return IRQ_HANDLED;} /* * fujitsu_disconnect() is the opposite of fujitsu_connect() */static void fujitsu_disconnect(struct serio *serio){	struct fujitsu *fujitsu = serio_get_drvdata(serio); 	input_get_device(fujitsu->dev);	input_unregister_device(fujitsu->dev);	serio_close(serio);	serio_set_drvdata(serio, NULL);	input_put_device(fujitsu->dev);	kfree(fujitsu);} /* * fujitsu_connect() is the routine that is called when someone adds a * new serio device that supports the Fujitsu protocol and registers it * as input device. */static int fujitsu_connect(struct serio *serio, struct serio_driver *drv){	struct fujitsu *fujitsu;	struct input_dev *input_dev;	int err; 	fujitsu = kzalloc_obj(*fujitsu);	input_dev = input_allocate_device();	if (!fujitsu || !input_dev) {		err = -ENOMEM;		goto fail1;	} 	fujitsu->serio = serio;	fujitsu->dev = input_dev;	scnprintf(fujitsu->phys, sizeof(fujitsu->phys), "%s/input0", serio->phys); 	input_dev->name = "Fujitsu Serial Touchscreen";	input_dev->phys = fujitsu->phys;	input_dev->id.bustype = BUS_RS232;	input_dev->id.vendor = SERIO_FUJITSU;	input_dev->id.product = 0;	input_dev->id.version = 0x0100;	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(input_dev, ABS_X, 0, 4096, 0, 0);	input_set_abs_params(input_dev, ABS_Y, 0, 4096, 0, 0);	serio_set_drvdata(serio, fujitsu); 	err = serio_open(serio, drv);	if (err)		goto fail2; 	err = input_register_device(fujitsu->dev);	if (err)		goto fail3; 	return 0;  fail3:	serio_close(serio); fail2:	serio_set_drvdata(serio, NULL); fail1:	input_free_device(input_dev);	kfree(fujitsu);	return err;} /* * The serio driver structure. */static const struct serio_device_id fujitsu_serio_ids[] = {	{		.type	= SERIO_RS232,		.proto	= SERIO_FUJITSU,		.id	= SERIO_ANY,		.extra	= SERIO_ANY,	},	{ 0 }}; MODULE_DEVICE_TABLE(serio, fujitsu_serio_ids); static struct serio_driver fujitsu_drv = {	.driver		= {		.name	= "fujitsu_ts",	},	.description	= DRIVER_DESC,	.id_table	= fujitsu_serio_ids,	.interrupt	= fujitsu_interrupt,	.connect	= fujitsu_connect,	.disconnect	= fujitsu_disconnect,}; module_serio_driver(fujitsu_drv);