LXR linux/drivers/input/touchscreen/hampshire.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Hampshire serial touchscreen driver
   4 *
   5 * Copyright (c) 2010 Adam Bennett
   6 * Based on the dynapro driver (c) Tias Guns
   7 */
   8
   9
  10/*
  11 * 2010/04/08 Adam Bennett <abennett72@gmail.com>
  12 *   Copied dynapro.c and edited for Hampshire 4-byte protocol
  13 */
  14
  15#include <linux/errno.h>
  16#include <linux/kernel.h>
  17#include <linux/module.h>
  18#include <linux/slab.h>
  19#include <linux/input.h>
  20#include <linux/serio.h>
  21
  22#define DRIVER_DESC     "Hampshire serial touchscreen driver"
  23
  24MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
  25MODULE_DESCRIPTION(DRIVER_DESC);
  26MODULE_LICENSE("GPL");
  27
  28/*
  29 * Definitions & global arrays.
  30 */
  31
  32#define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
  33#define HAMPSHIRE_FORMAT_LENGTH 4
  34#define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
  35
  36#define HAMPSHIRE_MIN_XC 0
  37#define HAMPSHIRE_MAX_XC 0x1000
  38#define HAMPSHIRE_MIN_YC 0
  39#define HAMPSHIRE_MAX_YC 0x1000
  40
  41#define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
  42#define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
  43#define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
  44
  45/*
  46 * Per-touchscreen data.
  47 */
  48
  49struct hampshire {
  50        struct input_dev *dev;
  51        struct serio *serio;
  52        int idx;
  53        unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
  54        char phys[32];
  55};
  56
  57static void hampshire_process_data(struct hampshire *phampshire)
  58{
  59        struct input_dev *dev = phampshire->dev;
  60
  61        if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
  62                input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
  63                input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
  64                input_report_key(dev, BTN_TOUCH,
  65                                 HAMPSHIRE_GET_TOUCHED(phampshire->data));
  66                input_sync(dev);
  67
  68                phampshire->idx = 0;
  69        }
  70}
  71
  72static irqreturn_t hampshire_interrupt(struct serio *serio,
  73                unsigned char data, unsigned int flags)
  74{
  75        struct hampshire *phampshire = serio_get_drvdata(serio);
  76
  77        phampshire->data[phampshire->idx] = data;
  78
  79        if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
  80                hampshire_process_data(phampshire);
  81        else
  82                dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
  83                        phampshire->data[0]);
  84
  85        return IRQ_HANDLED;
  86}
  87
  88static void hampshire_disconnect(struct serio *serio)
  89{
  90        struct hampshire *phampshire = serio_get_drvdata(serio);
  91
  92        input_get_device(phampshire->dev);
  93        input_unregister_device(phampshire->dev);
  94        serio_close(serio);
  95        serio_set_drvdata(serio, NULL);
  96        input_put_device(phampshire->dev);
  97        kfree(phampshire);
  98}
  99
 100/*
 101 * hampshire_connect() is the routine that is called when someone adds a
 102 * new serio device that supports hampshire protocol and registers it as
 103 * an input device. This is usually accomplished using inputattach.
 104 */
 105
 106static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
 107{
 108        struct hampshire *phampshire;
 109        struct input_dev *input_dev;
 110        int err;
 111
 112        phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL);
 113        input_dev = input_allocate_device();
 114        if (!phampshire || !input_dev) {
 115                err = -ENOMEM;
 116                goto fail1;
 117        }
 118
 119        phampshire->serio = serio;
 120        phampshire->dev = input_dev;
 121        snprintf(phampshire->phys, sizeof(phampshire->phys),
 122                 "%s/input0", serio->phys);
 123
 124        input_dev->name = "Hampshire Serial TouchScreen";
 125        input_dev->phys = phampshire->phys;
 126        input_dev->id.bustype = BUS_RS232;
 127        input_dev->id.vendor = SERIO_HAMPSHIRE;
 128        input_dev->id.product = 0;
 129        input_dev->id.version = 0x0001;
 130        input_dev->dev.parent = &serio->dev;
 131        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 132        input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 133        input_set_abs_params(phampshire->dev, ABS_X,
 134                             HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
 135        input_set_abs_params(phampshire->dev, ABS_Y,
 136                             HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
 137
 138        serio_set_drvdata(serio, phampshire);
 139
 140        err = serio_open(serio, drv);
 141        if (err)
 142                goto fail2;
 143
 144        err = input_register_device(phampshire->dev);
 145        if (err)
 146                goto fail3;
 147
 148        return 0;
 149
 150 fail3: serio_close(serio);
 151 fail2: serio_set_drvdata(serio, NULL);
 152 fail1: input_free_device(input_dev);
 153        kfree(phampshire);
 154        return err;
 155}
 156
 157/*
 158 * The serio driver structure.
 159 */
 160
 161static const struct serio_device_id hampshire_serio_ids[] = {
 162        {
 163                .type   = SERIO_RS232,
 164                .proto  = SERIO_HAMPSHIRE,
 165                .id     = SERIO_ANY,
 166                .extra  = SERIO_ANY,
 167        },
 168        { 0 }
 169};
 170
 171MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
 172
 173static struct serio_driver hampshire_drv = {
 174        .driver         = {
 175                .name   = "hampshire",
 176        },
 177        .description    = DRIVER_DESC,
 178        .id_table       = hampshire_serio_ids,
 179        .interrupt      = hampshire_interrupt,
 180        .connect        = hampshire_connect,
 181        .disconnect     = hampshire_disconnect,
 182};
 183
 184module_serio_driver(hampshire_drv);
 185