linux/drivers/input/joystick/twidjoy.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  Copyright (c) 2001 Arndt Schoenewald
   4 *  Copyright (c) 2000-2001 Vojtech Pavlik
   5 *  Copyright (c) 2000 Mark Fletcher
   6 *
   7 *  Sponsored by Quelltext AG (http://www.quelltext-ag.de), Dortmund, Germany
   8 */
   9
  10/*
  11 * Driver to use Handykey's Twiddler (the first edition, i.e. the one with
  12 * the RS232 interface) as a joystick under Linux
  13 *
  14 * The Twiddler is a one-handed chording keyboard featuring twelve buttons on
  15 * the front, six buttons on the top, and a built-in tilt sensor. The buttons
  16 * on the front, which are grouped as four rows of three buttons, are pressed
  17 * by the four fingers (this implies only one button per row can be held down
  18 * at the same time) and the buttons on the top are for the thumb. The tilt
  19 * sensor delivers X and Y axis data depending on how the Twiddler is held.
  20 * Additional information can be found at http://www.handykey.com.
  21 *
  22 * This driver does not use the Twiddler for its intended purpose, i.e. as
  23 * a chording keyboard, but as a joystick: pressing and releasing a button
  24 * immediately sends a corresponding button event, and tilting it generates
  25 * corresponding ABS_X and ABS_Y events. This turns the Twiddler into a game
  26 * controller with amazing 18 buttons :-)
  27 *
  28 * Note: The Twiddler2 (the successor of the Twiddler that connects directly
  29 * to the PS/2 keyboard and mouse ports) is NOT supported by this driver!
  30 *
  31 * For questions or feedback regarding this driver module please contact:
  32 * Arndt Schoenewald <arndt@quelltext.com>
  33 */
  34
  35/*
  36 */
  37
  38#include <linux/kernel.h>
  39#include <linux/module.h>
  40#include <linux/slab.h>
  41#include <linux/input.h>
  42#include <linux/serio.h>
  43
  44#define DRIVER_DESC     "Handykey Twiddler keyboard as a joystick driver"
  45
  46MODULE_DESCRIPTION(DRIVER_DESC);
  47MODULE_LICENSE("GPL");
  48
  49/*
  50 * Constants.
  51 */
  52
  53#define TWIDJOY_MAX_LENGTH 5
  54
  55static struct twidjoy_button_spec {
  56        int bitshift;
  57        int bitmask;
  58        int buttons[3];
  59}
  60twidjoy_buttons[] = {
  61        {  0, 3, { BTN_A,      BTN_B,     BTN_C    } },
  62        {  2, 3, { BTN_X,      BTN_Y,     BTN_Z    } },
  63        {  4, 3, { BTN_TL,     BTN_TR,    BTN_TR2  } },
  64        {  6, 3, { BTN_SELECT, BTN_START, BTN_MODE } },
  65        {  8, 1, { BTN_BASE5                       } },
  66        {  9, 1, { BTN_BASE                        } },
  67        { 10, 1, { BTN_BASE3                       } },
  68        { 11, 1, { BTN_BASE4                       } },
  69        { 12, 1, { BTN_BASE2                       } },
  70        { 13, 1, { BTN_BASE6                       } },
  71        { 0,  0, { 0                               } }
  72};
  73
  74/*
  75 * Per-Twiddler data.
  76 */
  77
  78struct twidjoy {
  79        struct input_dev *dev;
  80        int idx;
  81        unsigned char data[TWIDJOY_MAX_LENGTH];
  82        char phys[32];
  83};
  84
  85/*
  86 * twidjoy_process_packet() decodes packets the driver receives from the
  87 * Twiddler. It updates the data accordingly.
  88 */
  89
  90static void twidjoy_process_packet(struct twidjoy *twidjoy)
  91{
  92        struct input_dev *dev = twidjoy->dev;
  93        unsigned char *data = twidjoy->data;
  94        struct twidjoy_button_spec *bp;
  95        int button_bits, abs_x, abs_y;
  96
  97        button_bits = ((data[1] & 0x7f) << 7) | (data[0] & 0x7f);
  98
  99        for (bp = twidjoy_buttons; bp->bitmask; bp++) {
 100                int value = (button_bits & (bp->bitmask << bp->bitshift)) >> bp->bitshift;
 101                int i;
 102
 103                for (i = 0; i < bp->bitmask; i++)
 104                        input_report_key(dev, bp->buttons[i], i+1 == value);
 105        }
 106
 107        abs_x = ((data[4] & 0x07) << 5) | ((data[3] & 0x7C) >> 2);
 108        if (data[4] & 0x08) abs_x -= 256;
 109
 110        abs_y = ((data[3] & 0x01) << 7) | ((data[2] & 0x7F) >> 0);
 111        if (data[3] & 0x02) abs_y -= 256;
 112
 113        input_report_abs(dev, ABS_X, -abs_x);
 114        input_report_abs(dev, ABS_Y, +abs_y);
 115
 116        input_sync(dev);
 117}
 118
 119/*
 120 * twidjoy_interrupt() is called by the low level driver when characters
 121 * are ready for us. We then buffer them for further processing, or call the
 122 * packet processing routine.
 123 */
 124
 125static irqreturn_t twidjoy_interrupt(struct serio *serio, unsigned char data, unsigned int flags)
 126{
 127        struct twidjoy *twidjoy = serio_get_drvdata(serio);
 128
 129        /* All Twiddler packets are 5 bytes. The fact that the first byte
 130         * has a MSB of 0 and all other bytes have a MSB of 1 can be used
 131         * to check and regain sync. */
 132
 133        if ((data & 0x80) == 0)
 134                twidjoy->idx = 0;       /* this byte starts a new packet */
 135        else if (twidjoy->idx == 0)
 136                return IRQ_HANDLED;     /* wrong MSB -- ignore this byte */
 137
 138        if (twidjoy->idx < TWIDJOY_MAX_LENGTH)
 139                twidjoy->data[twidjoy->idx++] = data;
 140
 141        if (twidjoy->idx == TWIDJOY_MAX_LENGTH) {
 142                twidjoy_process_packet(twidjoy);
 143                twidjoy->idx = 0;
 144        }
 145
 146        return IRQ_HANDLED;
 147}
 148
 149/*
 150 * twidjoy_disconnect() is the opposite of twidjoy_connect()
 151 */
 152
 153static void twidjoy_disconnect(struct serio *serio)
 154{
 155        struct twidjoy *twidjoy = serio_get_drvdata(serio);
 156
 157        serio_close(serio);
 158        serio_set_drvdata(serio, NULL);
 159        input_unregister_device(twidjoy->dev);
 160        kfree(twidjoy);
 161}
 162
 163/*
 164 * twidjoy_connect() is the routine that is called when someone adds a
 165 * new serio device. It looks for the Twiddler, and if found, registers
 166 * it as an input device.
 167 */
 168
 169static int twidjoy_connect(struct serio *serio, struct serio_driver *drv)
 170{
 171        struct twidjoy_button_spec *bp;
 172        struct twidjoy *twidjoy;
 173        struct input_dev *input_dev;
 174        int err = -ENOMEM;
 175        int i;
 176
 177        twidjoy = kzalloc(sizeof(struct twidjoy), GFP_KERNEL);
 178        input_dev = input_allocate_device();
 179        if (!twidjoy || !input_dev)
 180                goto fail1;
 181
 182        twidjoy->dev = input_dev;
 183        snprintf(twidjoy->phys, sizeof(twidjoy->phys), "%s/input0", serio->phys);
 184
 185        input_dev->name = "Handykey Twiddler";
 186        input_dev->phys = twidjoy->phys;
 187        input_dev->id.bustype = BUS_RS232;
 188        input_dev->id.vendor = SERIO_TWIDJOY;
 189        input_dev->id.product = 0x0001;
 190        input_dev->id.version = 0x0100;
 191        input_dev->dev.parent = &serio->dev;
 192
 193        input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 194        input_set_abs_params(input_dev, ABS_X, -50, 50, 4, 4);
 195        input_set_abs_params(input_dev, ABS_Y, -50, 50, 4, 4);
 196
 197        for (bp = twidjoy_buttons; bp->bitmask; bp++)
 198                for (i = 0; i < bp->bitmask; i++)
 199                        set_bit(bp->buttons[i], input_dev->keybit);
 200
 201        serio_set_drvdata(serio, twidjoy);
 202
 203        err = serio_open(serio, drv);
 204        if (err)
 205                goto fail2;
 206
 207        err = input_register_device(twidjoy->dev);
 208        if (err)
 209                goto fail3;
 210
 211        return 0;
 212
 213 fail3: serio_close(serio);
 214 fail2: serio_set_drvdata(serio, NULL);
 215 fail1: input_free_device(input_dev);
 216        kfree(twidjoy);
 217        return err;
 218}
 219
 220/*
 221 * The serio driver structure.
 222 */
 223
 224static const struct serio_device_id twidjoy_serio_ids[] = {
 225        {
 226                .type   = SERIO_RS232,
 227                .proto  = SERIO_TWIDJOY,
 228                .id     = SERIO_ANY,
 229                .extra  = SERIO_ANY,
 230        },
 231        { 0 }
 232};
 233
 234MODULE_DEVICE_TABLE(serio, twidjoy_serio_ids);
 235
 236static struct serio_driver twidjoy_drv = {
 237        .driver         = {
 238                .name   = "twidjoy",
 239        },
 240        .description    = DRIVER_DESC,
 241        .id_table       = twidjoy_serio_ids,
 242        .interrupt      = twidjoy_interrupt,
 243        .connect        = twidjoy_connect,
 244        .disconnect     = twidjoy_disconnect,
 245};
 246
 247module_serio_driver(twidjoy_drv);
 248