drivers/input/joystick/walkera0701.c

   1 /*
   2  *  Parallel port to Walkera WK-0701 TX joystick
   3  *
   4  *  Copyright (c) 2008 Peter Popovec
   5  *
   6  *  More about driver:  <file:Documentation/input/devices/walkera0701.rst>
   7  */
   8
   9 /*
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License version 2 as published by
  12  * the Free Software Foundation.
  13 */
  14
  15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #define RESERVE 20000
  18 #define SYNC_PULSE 1306000
  19 #define BIN0_PULSE 288000
  20 #define BIN1_PULSE 438000
  21
  22 #define ANALOG_MIN_PULSE 318000
  23 #define ANALOG_MAX_PULSE 878000
  24 #define ANALOG_DELTA 80000
  25
  26 #define BIN_SAMPLE ((BIN0_PULSE + BIN1_PULSE) / 2)
  27
  28 #define NO_SYNC 25
  29
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/parport.h>
  33 #include <linux/input.h>
  34 #include <linux/hrtimer.h>
  35
  36 MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
  37 MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
  38 MODULE_LICENSE("GPL");
  39
  40 static unsigned int walkera0701_pp_no;
  41 module_param_named(port, walkera0701_pp_no, int, 0);
  42 MODULE_PARM_DESC(port,
  43                  "Parallel port adapter for Walkera WK-0701 TX (default is 0)");
  44
  45 /*
  46  * For now, only one device is supported, if somebody need more devices, code
  47  * can be expanded, one struct walkera_dev per device must be allocated and
  48  * set up by walkera0701_connect (release of device by walkera0701_disconnect)
  49  */
  50
  51 struct walkera_dev {
  52         unsigned char buf[25];
  53         u64 irq_time, irq_lasttime;
  54         int counter;
  55         int ack;
  56
  57         struct input_dev *input_dev;
  58         struct hrtimer timer;
  59
  60         struct parport *parport;
  61         struct pardevice *pardevice;
  62 };
  63
  64 static struct walkera_dev w_dev;
  65
  66 static inline void walkera0701_parse_frame(struct walkera_dev *w)
  67 {
  68         int i;
  69         int val1, val2, val3, val4, val5, val6, val7, val8;
  70         int magic, magic_bit;
  71         int crc1, crc2;
  72
  73         for (crc1 = crc2 = i = 0; i < 10; i++) {
  74                 crc1 += w->buf[i] & 7;
  75                 crc2 += (w->buf[i] & 8) >> 3;
  76         }
  77         if ((w->buf[10] & 7) != (crc1 & 7))
  78                 return;
  79         if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  80                 return;
  81         for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
  82                 crc1 += w->buf[i] & 7;
  83                 crc2 += (w->buf[i] & 8) >> 3;
  84         }
  85         if ((w->buf[23] & 7) != (crc1 & 7))
  86                 return;
  87         if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  88                 return;
  89         val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
  90         val1 *= ((w->buf[0] >> 2) & 2) - 1;     /* sign */
  91         val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
  92         val2 *= (w->buf[2] & 2) - 1;    /* sign */
  93         val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
  94         val3 *= ((w->buf[5] >> 2) & 2) - 1;     /* sign */
  95         val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
  96         val4 *= (w->buf[7] & 2) - 1;    /* sign */
  97         val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
  98         val5 *= ((w->buf[11] >> 2) & 2) - 1;    /* sign */
  99         val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
 100         val6 *= (w->buf[13] & 2) - 1;   /* sign */
 101         val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
 102         val7 *= ((w->buf[16] >> 2) & 2) - 1;    /*sign */
 103         val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
 104         val8 *= (w->buf[18] & 2) - 1;   /*sign */
 105
 106         magic = (w->buf[21] << 4) | w->buf[22];
 107         magic_bit = (w->buf[24] & 8) >> 3;
 108         pr_debug("%4d %4d %4d %4d  %4d %4d %4d %4d (magic %2x %d)\n",
 109                  val1, val2, val3, val4, val5, val6, val7, val8,
 110                  magic, magic_bit);
 111
 112         input_report_abs(w->input_dev, ABS_X, val2);
 113         input_report_abs(w->input_dev, ABS_Y, val1);
 114         input_report_abs(w->input_dev, ABS_Z, val6);
 115         input_report_abs(w->input_dev, ABS_THROTTLE, val3);
 116         input_report_abs(w->input_dev, ABS_RUDDER, val4);
 117         input_report_abs(w->input_dev, ABS_MISC, val7);
 118         input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
 119 }
 120
 121 static inline int read_ack(struct pardevice *p)
 122 {
 123         return parport_read_status(p->port) & 0x40;
 124 }
 125
 126 /* falling edge, prepare to BIN value calculation */
 127 static void walkera0701_irq_handler(void *handler_data)
 128 {
 129         u64 pulse_time;
 130         struct walkera_dev *w = handler_data;
 131
 132         w->irq_time = ktime_to_ns(ktime_get());
 133         pulse_time = w->irq_time - w->irq_lasttime;
 134         w->irq_lasttime = w->irq_time;
 135
 136         /* cancel timer, if in handler or active do resync */
 137         if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
 138                 w->counter = NO_SYNC;
 139                 return;
 140         }
 141
 142         if (w->counter < NO_SYNC) {
 143                 if (w->ack) {
 144                         pulse_time -= BIN1_PULSE;
 145                         w->buf[w->counter] = 8;
 146                 } else {
 147                         pulse_time -= BIN0_PULSE;
 148                         w->buf[w->counter] = 0;
 149                 }
 150                 if (w->counter == 24) { /* full frame */
 151                         walkera0701_parse_frame(w);
 152                         w->counter = NO_SYNC;
 153                         if (abs(pulse_time - SYNC_PULSE) < RESERVE)     /* new frame sync */
 154                                 w->counter = 0;
 155                 } else {
 156                         if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
 157                              && (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
 158                                 pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
 159                                 pulse_time = (u32) pulse_time / ANALOG_DELTA;   /* overtiping is safe, pulsetime < s32.. */
 160                                 w->buf[w->counter++] |= (pulse_time & 7);
 161                         } else
 162                                 w->counter = NO_SYNC;
 163                 }
 164         } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
 165                                 RESERVE + BIN1_PULSE - BIN0_PULSE)      /* frame sync .. */
 166                 w->counter = 0;
 167
 168         hrtimer_start(&w->timer, BIN_SAMPLE, HRTIMER_MODE_REL);
 169 }
 170
 171 static enum hrtimer_restart timer_handler(struct hrtimer
 172                                           *handle)
 173 {
 174         struct walkera_dev *w;
 175
 176         w = container_of(handle, struct walkera_dev, timer);
 177         w->ack = read_ack(w->pardevice);
 178
 179         return HRTIMER_NORESTART;
 180 }
 181
 182 static int walkera0701_open(struct input_dev *dev)
 183 {
 184         struct walkera_dev *w = input_get_drvdata(dev);
 185
 186         if (parport_claim(w->pardevice))
 187                 return -EBUSY;
 188
 189         parport_enable_irq(w->parport);
 190         return 0;
 191 }
 192
 193 static void walkera0701_close(struct input_dev *dev)
 194 {
 195         struct walkera_dev *w = input_get_drvdata(dev);
 196
 197         parport_disable_irq(w->parport);
 198         hrtimer_cancel(&w->timer);
 199
 200         parport_release(w->pardevice);
 201 }
 202
 203 static void walkera0701_attach(struct parport *pp)
 204 {
 205         struct pardev_cb walkera0701_parport_cb;
 206         struct walkera_dev *w = &w_dev;
 207
 208         if (pp->number != walkera0701_pp_no) {
 209                 pr_debug("Not using parport%d.\n", pp->number);
 210                 return;
 211         }
 212
 213         if (pp->irq == -1) {
 214                 pr_err("parport %d does not have interrupt assigned\n",
 215                         pp->number);
 216                 return;
 217         }
 218
 219         w->parport = pp;
 220
 221         memset(&walkera0701_parport_cb, 0, sizeof(walkera0701_parport_cb));
 222         walkera0701_parport_cb.flags = PARPORT_FLAG_EXCL;
 223         walkera0701_parport_cb.irq_func = walkera0701_irq_handler;
 224         walkera0701_parport_cb.private = w;
 225
 226         w->pardevice = parport_register_dev_model(pp, "walkera0701",
 227                                                   &walkera0701_parport_cb, 0);
 228
 229         if (!w->pardevice) {
 230                 pr_err("failed to register parport device\n");
 231                 return;
 232         }
 233
 234         if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) {
 235                 pr_err("failed to negotiate parport mode\n");
 236                 goto err_unregister_device;
 237         }
 238
 239         hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 240         w->timer.function = timer_handler;
 241
 242         w->input_dev = input_allocate_device();
 243         if (!w->input_dev) {
 244                 pr_err("failed to allocate input device\n");
 245                 goto err_unregister_device;
 246         }
 247
 248         input_set_drvdata(w->input_dev, w);
 249         w->input_dev->name = "Walkera WK-0701 TX";
 250         w->input_dev->phys = w->parport->name;
 251         w->input_dev->id.bustype = BUS_PARPORT;
 252
 253         /* TODO what id vendor/product/version ? */
 254         w->input_dev->id.vendor = 0x0001;
 255         w->input_dev->id.product = 0x0001;
 256         w->input_dev->id.version = 0x0100;
 257         w->input_dev->dev.parent = w->parport->dev;
 258         w->input_dev->open = walkera0701_open;
 259         w->input_dev->close = walkera0701_close;
 260
 261         w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
 262         w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
 263
 264         input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
 265         input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
 266         input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
 267         input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
 268         input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
 269         input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
 270
 271         if (input_register_device(w->input_dev)) {
 272                 pr_err("failed to register input device\n");
 273                 goto err_free_input_dev;
 274         }
 275
 276         return;
 277
 278 err_free_input_dev:
 279         input_free_device(w->input_dev);
 280 err_unregister_device:
 281         parport_unregister_device(w->pardevice);
 282 }
 283
 284 static void walkera0701_detach(struct parport *port)
 285 {
 286         struct walkera_dev *w = &w_dev;
 287
 288         if (!w->pardevice || w->parport->number != port->number)
 289                 return;
 290
 291         input_unregister_device(w->input_dev);
 292         parport_unregister_device(w->pardevice);
 293         w->parport = NULL;
 294 }
 295
 296 static struct parport_driver walkera0701_parport_driver = {
 297         .name = "walkera0701",
 298         .match_port = walkera0701_attach,
 299         .detach = walkera0701_detach,
 300         .devmodel = true,
 301 };
 302
 303 static int __init walkera0701_init(void)
 304 {
 305         return parport_register_driver(&walkera0701_parport_driver);
 306 }
 307
 308 static void __exit walkera0701_exit(void)
 309 {
 310         parport_unregister_driver(&walkera0701_parport_driver);
 311 }
 312
 313 module_init(walkera0701_init);
 314 module_exit(walkera0701_exit);