drivers/input/joystick/walkera0701.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Parallel port to Walkera WK-0701 TX joystick
   4  *
   5  *  Copyright (c) 2008 Peter Popovec
   6  *
   7  *  More about driver:  <file:Documentation/input/devices/walkera0701.rst>
   8  */
   9
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #define RESERVE 20000
  14 #define SYNC_PULSE 1306000
  15 #define BIN0_PULSE 288000
  16 #define BIN1_PULSE 438000
  17
  18 #define ANALOG_MIN_PULSE 318000
  19 #define ANALOG_MAX_PULSE 878000
  20 #define ANALOG_DELTA 80000
  21
  22 #define BIN_SAMPLE ((BIN0_PULSE + BIN1_PULSE) / 2)
  23
  24 #define NO_SYNC 25
  25
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/parport.h>
  29 #include <linux/input.h>
  30 #include <linux/hrtimer.h>
  31
  32 MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
  33 MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
  34 MODULE_LICENSE("GPL");
  35
  36 static unsigned int walkera0701_pp_no;
  37 module_param_named(port, walkera0701_pp_no, int, 0);
  38 MODULE_PARM_DESC(port,
  39                  "Parallel port adapter for Walkera WK-0701 TX (default is 0)");
  40
  41 /*
  42  * For now, only one device is supported, if somebody need more devices, code
  43  * can be expanded, one struct walkera_dev per device must be allocated and
  44  * set up by walkera0701_connect (release of device by walkera0701_disconnect)
  45  */
  46
  47 struct walkera_dev {
  48         unsigned char buf[25];
  49         u64 irq_time, irq_lasttime;
  50         int counter;
  51         int ack;
  52
  53         struct input_dev *input_dev;
  54         struct hrtimer timer;
  55
  56         struct parport *parport;
  57         struct pardevice *pardevice;
  58 };
  59
  60 static struct walkera_dev w_dev;
  61
  62 static inline void walkera0701_parse_frame(struct walkera_dev *w)
  63 {
  64         int i;
  65         int val1, val2, val3, val4, val5, val6, val7, val8;
  66         int magic, magic_bit;
  67         int crc1, crc2;
  68
  69         for (crc1 = crc2 = i = 0; i < 10; i++) {
  70                 crc1 += w->buf[i] & 7;
  71                 crc2 += (w->buf[i] & 8) >> 3;
  72         }
  73         if ((w->buf[10] & 7) != (crc1 & 7))
  74                 return;
  75         if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  76                 return;
  77         for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
  78                 crc1 += w->buf[i] & 7;
  79                 crc2 += (w->buf[i] & 8) >> 3;
  80         }
  81         if ((w->buf[23] & 7) != (crc1 & 7))
  82                 return;
  83         if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  84                 return;
  85         val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
  86         val1 *= ((w->buf[0] >> 2) & 2) - 1;     /* sign */
  87         val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
  88         val2 *= (w->buf[2] & 2) - 1;    /* sign */
  89         val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
  90         val3 *= ((w->buf[5] >> 2) & 2) - 1;     /* sign */
  91         val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
  92         val4 *= (w->buf[7] & 2) - 1;    /* sign */
  93         val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
  94         val5 *= ((w->buf[11] >> 2) & 2) - 1;    /* sign */
  95         val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
  96         val6 *= (w->buf[13] & 2) - 1;   /* sign */
  97         val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
  98         val7 *= ((w->buf[16] >> 2) & 2) - 1;    /*sign */
  99         val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
 100         val8 *= (w->buf[18] & 2) - 1;   /*sign */
 101
 102         magic = (w->buf[21] << 4) | w->buf[22];
 103         magic_bit = (w->buf[24] & 8) >> 3;
 104         pr_debug("%4d %4d %4d %4d  %4d %4d %4d %4d (magic %2x %d)\n",
 105                  val1, val2, val3, val4, val5, val6, val7, val8,
 106                  magic, magic_bit);
 107
 108         input_report_abs(w->input_dev, ABS_X, val2);
 109         input_report_abs(w->input_dev, ABS_Y, val1);
 110         input_report_abs(w->input_dev, ABS_Z, val6);
 111         input_report_abs(w->input_dev, ABS_THROTTLE, val3);
 112         input_report_abs(w->input_dev, ABS_RUDDER, val4);
 113         input_report_abs(w->input_dev, ABS_MISC, val7);
 114         input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
 115 }
 116
 117 static inline int read_ack(struct pardevice *p)
 118 {
 119         return parport_read_status(p->port) & 0x40;
 120 }
 121
 122 /* falling edge, prepare to BIN value calculation */
 123 static void walkera0701_irq_handler(void *handler_data)
 124 {
 125         u64 pulse_time;
 126         struct walkera_dev *w = handler_data;
 127
 128         w->irq_time = ktime_to_ns(ktime_get());
 129         pulse_time = w->irq_time - w->irq_lasttime;
 130         w->irq_lasttime = w->irq_time;
 131
 132         /* cancel timer, if in handler or active do resync */
 133         if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
 134                 w->counter = NO_SYNC;
 135                 return;
 136         }
 137
 138         if (w->counter < NO_SYNC) {
 139                 if (w->ack) {
 140                         pulse_time -= BIN1_PULSE;
 141                         w->buf[w->counter] = 8;
 142                 } else {
 143                         pulse_time -= BIN0_PULSE;
 144                         w->buf[w->counter] = 0;
 145                 }
 146                 if (w->counter == 24) { /* full frame */
 147                         walkera0701_parse_frame(w);
 148                         w->counter = NO_SYNC;
 149                         if (abs(pulse_time - SYNC_PULSE) < RESERVE)     /* new frame sync */
 150                                 w->counter = 0;
 151                 } else {
 152                         if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
 153                              && (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
 154                                 pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
 155                                 pulse_time = (u32) pulse_time / ANALOG_DELTA;   /* overtiping is safe, pulsetime < s32.. */
 156                                 w->buf[w->counter++] |= (pulse_time & 7);
 157                         } else
 158                                 w->counter = NO_SYNC;
 159                 }
 160         } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
 161                                 RESERVE + BIN1_PULSE - BIN0_PULSE)      /* frame sync .. */
 162                 w->counter = 0;
 163
 164         hrtimer_start(&w->timer, BIN_SAMPLE, HRTIMER_MODE_REL);
 165 }
 166
 167 static enum hrtimer_restart timer_handler(struct hrtimer
 168                                           *handle)
 169 {
 170         struct walkera_dev *w;
 171
 172         w = container_of(handle, struct walkera_dev, timer);
 173         w->ack = read_ack(w->pardevice);
 174
 175         return HRTIMER_NORESTART;
 176 }
 177
 178 static int walkera0701_open(struct input_dev *dev)
 179 {
 180         struct walkera_dev *w = input_get_drvdata(dev);
 181
 182         if (parport_claim(w->pardevice))
 183                 return -EBUSY;
 184
 185         parport_enable_irq(w->parport);
 186         return 0;
 187 }
 188
 189 static void walkera0701_close(struct input_dev *dev)
 190 {
 191         struct walkera_dev *w = input_get_drvdata(dev);
 192
 193         parport_disable_irq(w->parport);
 194         hrtimer_cancel(&w->timer);
 195
 196         parport_release(w->pardevice);
 197 }
 198
 199 static void walkera0701_attach(struct parport *pp)
 200 {
 201         struct pardev_cb walkera0701_parport_cb;
 202         struct walkera_dev *w = &w_dev;
 203
 204         if (pp->number != walkera0701_pp_no) {
 205                 pr_debug("Not using parport%d.\n", pp->number);
 206                 return;
 207         }
 208
 209         if (pp->irq == -1) {
 210                 pr_err("parport %d does not have interrupt assigned\n",
 211                         pp->number);
 212                 return;
 213         }
 214
 215         w->parport = pp;
 216
 217         memset(&walkera0701_parport_cb, 0, sizeof(walkera0701_parport_cb));
 218         walkera0701_parport_cb.flags = PARPORT_FLAG_EXCL;
 219         walkera0701_parport_cb.irq_func = walkera0701_irq_handler;
 220         walkera0701_parport_cb.private = w;
 221
 222         w->pardevice = parport_register_dev_model(pp, "walkera0701",
 223                                                   &walkera0701_parport_cb, 0);
 224
 225         if (!w->pardevice) {
 226                 pr_err("failed to register parport device\n");
 227                 return;
 228         }
 229
 230         if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) {
 231                 pr_err("failed to negotiate parport mode\n");
 232                 goto err_unregister_device;
 233         }
 234
 235         hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 236         w->timer.function = timer_handler;
 237
 238         w->input_dev = input_allocate_device();
 239         if (!w->input_dev) {
 240                 pr_err("failed to allocate input device\n");
 241                 goto err_unregister_device;
 242         }
 243
 244         input_set_drvdata(w->input_dev, w);
 245         w->input_dev->name = "Walkera WK-0701 TX";
 246         w->input_dev->phys = w->parport->name;
 247         w->input_dev->id.bustype = BUS_PARPORT;
 248
 249         /* TODO what id vendor/product/version ? */
 250         w->input_dev->id.vendor = 0x0001;
 251         w->input_dev->id.product = 0x0001;
 252         w->input_dev->id.version = 0x0100;
 253         w->input_dev->dev.parent = w->parport->dev;
 254         w->input_dev->open = walkera0701_open;
 255         w->input_dev->close = walkera0701_close;
 256
 257         w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
 258         w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
 259
 260         input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
 261         input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
 262         input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
 263         input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
 264         input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
 265         input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
 266
 267         if (input_register_device(w->input_dev)) {
 268                 pr_err("failed to register input device\n");
 269                 goto err_free_input_dev;
 270         }
 271
 272         return;
 273
 274 err_free_input_dev:
 275         input_free_device(w->input_dev);
 276 err_unregister_device:
 277         parport_unregister_device(w->pardevice);
 278 }
 279
 280 static void walkera0701_detach(struct parport *port)
 281 {
 282         struct walkera_dev *w = &w_dev;
 283
 284         if (!w->pardevice || w->parport->number != port->number)
 285                 return;
 286
 287         input_unregister_device(w->input_dev);
 288         parport_unregister_device(w->pardevice);
 289         w->parport = NULL;
 290 }
 291
 292 static struct parport_driver walkera0701_parport_driver = {
 293         .name = "walkera0701",
 294         .match_port = walkera0701_attach,
 295         .detach = walkera0701_detach,
 296         .devmodel = true,
 297 };
 298
 299 static int __init walkera0701_init(void)
 300 {
 301         return parport_register_driver(&walkera0701_parport_driver);
 302 }
 303
 304 static void __exit walkera0701_exit(void)
 305 {
 306         parport_unregister_driver(&walkera0701_parport_driver);
 307 }
 308
 309 module_init(walkera0701_init);
 310 module_exit(walkera0701_exit);