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// SPDX-License-Identifier: GPL-2.0-only
/*
* Hampshire serial touchscreen driver
*
* Copyright (c) 2010 Adam Bennett
* Based on the dynapro driver (c) Tias Guns
*/
/*
* 2010/04/08 Adam Bennett <abennett72@gmail.com>
* Copied dynapro.c and edited for Hampshire 4-byte protocol
*/
#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 "Hampshire serial touchscreen driver"
MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
/*
* Definitions & global arrays.
*/
#define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
#define HAMPSHIRE_FORMAT_LENGTH 4
#define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
#define HAMPSHIRE_MIN_XC 0
#define HAMPSHIRE_MAX_XC 0x1000
#define HAMPSHIRE_MIN_YC 0
#define HAMPSHIRE_MAX_YC 0x1000
#define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
#define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
#define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
/*
* Per-touchscreen data.
*/
struct hampshire {
struct input_dev *dev;
struct serio *serio;
int idx;
unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
char phys[32];
};
static void hampshire_process_data(struct hampshire *phampshire)
{
struct input_dev *dev = phampshire->dev;
if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
input_report_key(dev, BTN_TOUCH,
HAMPSHIRE_GET_TOUCHED(phampshire->data));
input_sync(dev);
phampshire->idx = 0;
}
}
static irqreturn_t hampshire_interrupt(struct serio *serio,
unsigned char data, unsigned int flags)
{
struct hampshire *phampshire = serio_get_drvdata(serio);
phampshire->data[phampshire->idx] = data;
if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
hampshire_process_data(phampshire);
else
dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
phampshire->data[0]);
return IRQ_HANDLED;
}
static void hampshire_disconnect(struct serio *serio)
{
struct hampshire *phampshire = serio_get_drvdata(serio);
input_get_device(phampshire->dev);
input_unregister_device(phampshire->dev);
serio_close(serio);
serio_set_drvdata(serio, NULL);
input_put_device(phampshire->dev);
kfree(phampshire);
}
/*
* hampshire_connect() is the routine that is called when someone adds a
* new serio device that supports hampshire protocol and registers it as
* an input device. This is usually accomplished using inputattach.
*/
static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
{
struct hampshire *phampshire;
struct input_dev *input_dev;
int err;
phampshire = kzalloc(sizeof(*phampshire), GFP_KERNEL);
input_dev = input_allocate_device();
if (!phampshire || !input_dev) {
err = -ENOMEM;
goto fail1;
}
phampshire->serio = serio;
phampshire->dev = input_dev;
snprintf(phampshire->phys, sizeof(phampshire->phys),
"%s/input0", serio->phys);
input_dev->name = "Hampshire Serial TouchScreen";
input_dev->phys = phampshire->phys;
input_dev->id.bustype = BUS_RS232;
input_dev->id.vendor = SERIO_HAMPSHIRE;
input_dev->id.product = 0;
input_dev->id.version = 0x0001;
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(phampshire->dev, ABS_X,
HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
input_set_abs_params(phampshire->dev, ABS_Y,
HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
serio_set_drvdata(serio, phampshire);
err = serio_open(serio, drv);
if (err)
goto fail2;
err = input_register_device(phampshire->dev);
if (err)
goto fail3;
return 0;
fail3: serio_close(serio);
fail2: serio_set_drvdata(serio, NULL);
fail1: input_free_device(input_dev);
kfree(phampshire);
return err;
}
/*
* The serio driver structure.
*/
static const struct serio_device_id hampshire_serio_ids[] = {
{
.type = SERIO_RS232,
.proto = SERIO_HAMPSHIRE,
.id = SERIO_ANY,
.extra = SERIO_ANY,
},
{ 0 }
};
MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
static struct serio_driver hampshire_drv = {
.driver = {
.name = "hampshire",
},
.description = DRIVER_DESC,
.id_table = hampshire_serio_ids,
.interrupt = hampshire_interrupt,
.connect = hampshire_connect,
.disconnect = hampshire_disconnect,
};
module_serio_driver(hampshire_drv);
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