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/walkera0701.txt>
   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 WK0701_DEBUG */
  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 crc1, crc2;
  71
  72         for (crc1 = crc2 = i = 0; i < 10; i++) {
  73                 crc1 += w->buf[i] & 7;
  74                 crc2 += (w->buf[i] & 8) >> 3;
  75         }
  76         if ((w->buf[10] & 7) != (crc1 & 7))
  77                 return;
  78         if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  79                 return;
  80         for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
  81                 crc1 += w->buf[i] & 7;
  82                 crc2 += (w->buf[i] & 8) >> 3;
  83         }
  84         if ((w->buf[23] & 7) != (crc1 & 7))
  85                 return;
  86         if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  87                 return;
  88         val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
  89         val1 *= ((w->buf[0] >> 2) & 2) - 1;     /* sign */
  90         val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
  91         val2 *= (w->buf[2] & 2) - 1;    /* sign */
  92         val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
  93         val3 *= ((w->buf[5] >> 2) & 2) - 1;     /* sign */
  94         val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
  95         val4 *= (w->buf[7] & 2) - 1;    /* sign */
  96         val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
  97         val5 *= ((w->buf[11] >> 2) & 2) - 1;    /* sign */
  98         val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
  99         val6 *= (w->buf[13] & 2) - 1;   /* sign */
 100         val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
 101         val7 *= ((w->buf[16] >> 2) & 2) - 1;    /*sign */
 102         val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
 103         val8 *= (w->buf[18] & 2) - 1;   /*sign */
 104
 105 #ifdef WK0701_DEBUG
 106         {
 107                 int magic, magic_bit;
 108                 magic = (w->buf[21] << 4) | w->buf[22];
 109                 magic_bit = (w->buf[24] & 8) >> 3;
 110                 printk(KERN_DEBUG
 111                        "walkera0701: %4d %4d %4d %4d  %4d %4d %4d %4d (magic %2x %d)\n",
 112                        val1, val2, val3, val4, val5, val6, val7, val8, magic,
 113                        magic_bit);
 114         }
 115 #endif
 116         input_report_abs(w->input_dev, ABS_X, val2);
 117         input_report_abs(w->input_dev, ABS_Y, val1);
 118         input_report_abs(w->input_dev, ABS_Z, val6);
 119         input_report_abs(w->input_dev, ABS_THROTTLE, val3);
 120         input_report_abs(w->input_dev, ABS_RUDDER, val4);
 121         input_report_abs(w->input_dev, ABS_MISC, val7);
 122         input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
 123 }
 124
 125 static inline int read_ack(struct pardevice *p)
 126 {
 127         return parport_read_status(p->port) & 0x40;
 128 }
 129
 130 /* falling edge, prepare to BIN value calculation */
 131 static void walkera0701_irq_handler(void *handler_data)
 132 {
 133         u64 pulse_time;
 134         struct walkera_dev *w = handler_data;
 135
 136         w->irq_time = ktime_to_ns(ktime_get());
 137         pulse_time = w->irq_time - w->irq_lasttime;
 138         w->irq_lasttime = w->irq_time;
 139
 140         /* cancel timer, if in handler or active do resync */
 141         if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
 142                 w->counter = NO_SYNC;
 143                 return;
 144         }
 145
 146         if (w->counter < NO_SYNC) {
 147                 if (w->ack) {
 148                         pulse_time -= BIN1_PULSE;
 149                         w->buf[w->counter] = 8;
 150                 } else {
 151                         pulse_time -= BIN0_PULSE;
 152                         w->buf[w->counter] = 0;
 153                 }
 154                 if (w->counter == 24) { /* full frame */
 155                         walkera0701_parse_frame(w);
 156                         w->counter = NO_SYNC;
 157                         if (abs(pulse_time - SYNC_PULSE) < RESERVE)     /* new frame sync */
 158                                 w->counter = 0;
 159                 } else {
 160                         if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
 161                              && (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
 162                                 pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
 163                                 pulse_time = (u32) pulse_time / ANALOG_DELTA;   /* overtiping is safe, pulsetime < s32.. */
 164                                 w->buf[w->counter++] |= (pulse_time & 7);
 165                         } else
 166                                 w->counter = NO_SYNC;
 167                 }
 168         } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
 169                                 RESERVE + BIN1_PULSE - BIN0_PULSE)      /* frame sync .. */
 170                 w->counter = 0;
 171
 172         hrtimer_start(&w->timer, ktime_set(0, BIN_SAMPLE), HRTIMER_MODE_REL);
 173 }
 174
 175 static enum hrtimer_restart timer_handler(struct hrtimer
 176                                           *handle)
 177 {
 178         struct walkera_dev *w;
 179
 180         w = container_of(handle, struct walkera_dev, timer);
 181         w->ack = read_ack(w->pardevice);
 182
 183         return HRTIMER_NORESTART;
 184 }
 185
 186 static int walkera0701_open(struct input_dev *dev)
 187 {
 188         struct walkera_dev *w = input_get_drvdata(dev);
 189
 190         parport_enable_irq(w->parport);
 191         return 0;
 192 }
 193
 194 static void walkera0701_close(struct input_dev *dev)
 195 {
 196         struct walkera_dev *w = input_get_drvdata(dev);
 197
 198         parport_disable_irq(w->parport);
 199 }
 200
 201 static int walkera0701_connect(struct walkera_dev *w, int parport)
 202 {
 203         int err = -ENODEV;
 204
 205         w->parport = parport_find_number(parport);
 206         if (w->parport == NULL)
 207                 return -ENODEV;
 208
 209         if (w->parport->irq == -1) {
 210                 printk(KERN_ERR "walkera0701: parport without interrupt\n");
 211                 goto init_err;
 212         }
 213
 214         err = -EBUSY;
 215         w->pardevice = parport_register_device(w->parport, "walkera0701",
 216                                     NULL, NULL, walkera0701_irq_handler,
 217                                     PARPORT_DEV_EXCL, w);
 218         if (!w->pardevice)
 219                 goto init_err;
 220
 221         if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT))
 222                 goto init_err1;
 223
 224         if (parport_claim(w->pardevice))
 225                 goto init_err1;
 226
 227         w->input_dev = input_allocate_device();
 228         if (!w->input_dev)
 229                 goto init_err2;
 230
 231         input_set_drvdata(w->input_dev, w);
 232         w->input_dev->name = "Walkera WK-0701 TX";
 233         w->input_dev->phys = w->parport->name;
 234         w->input_dev->id.bustype = BUS_PARPORT;
 235
 236         /* TODO what id vendor/product/version ? */
 237         w->input_dev->id.vendor = 0x0001;
 238         w->input_dev->id.product = 0x0001;
 239         w->input_dev->id.version = 0x0100;
 240         w->input_dev->open = walkera0701_open;
 241         w->input_dev->close = walkera0701_close;
 242
 243         w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
 244         w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
 245
 246         input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
 247         input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
 248         input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
 249         input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
 250         input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
 251         input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
 252
 253         err = input_register_device(w->input_dev);
 254         if (err)
 255                 goto init_err3;
 256
 257         hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 258         w->timer.function = timer_handler;
 259         return 0;
 260
 261  init_err3:
 262         input_free_device(w->input_dev);
 263  init_err2:
 264         parport_release(w->pardevice);
 265  init_err1:
 266         parport_unregister_device(w->pardevice);
 267  init_err:
 268         parport_put_port(w->parport);
 269         return err;
 270 }
 271
 272 static void walkera0701_disconnect(struct walkera_dev *w)
 273 {
 274         hrtimer_cancel(&w->timer);
 275         input_unregister_device(w->input_dev);
 276         parport_release(w->pardevice);
 277         parport_unregister_device(w->pardevice);
 278         parport_put_port(w->parport);
 279 }
 280
 281 static int __init walkera0701_init(void)
 282 {
 283         return walkera0701_connect(&w_dev, walkera0701_pp_no);
 284 }
 285
 286 static void __exit walkera0701_exit(void)
 287 {
 288         walkera0701_disconnect(&w_dev);
 289 }
 290
 291 module_init(walkera0701_init);
 292 module_exit(walkera0701_exit);