input/joystick/walkera0701.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *  Parallel port to Walkera WK-0701 TX joystick
0004  *
0005  *  Copyright (c) 2008 Peter Popovec
0006  *
0007  *  More about driver:  <file:Documentation/input/devices/walkera0701.rst>
0008  */
0009
0010
0011 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0012
0013 #define RESERVE 20000
0014 #define SYNC_PULSE 1306000
0015 #define BIN0_PULSE 288000
0016 #define BIN1_PULSE 438000
0017
0018 #define ANALOG_MIN_PULSE 318000
0019 #define ANALOG_MAX_PULSE 878000
0020 #define ANALOG_DELTA 80000
0021
0022 #define BIN_SAMPLE ((BIN0_PULSE + BIN1_PULSE) / 2)
0023
0024 #define NO_SYNC 25
0025
0026 #include <linux/kernel.h>
0027 #include <linux/module.h>
0028 #include <linux/parport.h>
0029 #include <linux/input.h>
0030 #include <linux/hrtimer.h>
0031
0032 MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
0033 MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
0034 MODULE_LICENSE("GPL");
0035
0036 static unsigned int walkera0701_pp_no;
0037 module_param_named(port, walkera0701_pp_no, int, 0);
0038 MODULE_PARM_DESC(port,
0039          "Parallel port adapter for Walkera WK-0701 TX (default is 0)");
0040
0041 /*
0042  * For now, only one device is supported, if somebody need more devices, code
0043  * can be expanded, one struct walkera_dev per device must be allocated and
0044  * set up by walkera0701_connect (release of device by walkera0701_disconnect)
0045  */
0046
0047 struct walkera_dev {
0048     unsigned char buf[25];
0049     u64 irq_time, irq_lasttime;
0050     int counter;
0051     int ack;
0052
0053     struct input_dev *input_dev;
0054     struct hrtimer timer;
0055
0056     struct parport *parport;
0057     struct pardevice *pardevice;
0058 };
0059
0060 static struct walkera_dev w_dev;
0061
0062 static inline void walkera0701_parse_frame(struct walkera_dev *w)
0063 {
0064     int i;
0065     int val1, val2, val3, val4, val5, val6, val7, val8;
0066     int magic, magic_bit;
0067     int crc1, crc2;
0068
0069     for (crc1 = crc2 = i = 0; i < 10; i++) {
0070         crc1 += w->buf[i] & 7;
0071         crc2 += (w->buf[i] & 8) >> 3;
0072     }
0073     if ((w->buf[10] & 7) != (crc1 & 7))
0074         return;
0075     if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
0076         return;
0077     for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
0078         crc1 += w->buf[i] & 7;
0079         crc2 += (w->buf[i] & 8) >> 3;
0080     }
0081     if ((w->buf[23] & 7) != (crc1 & 7))
0082         return;
0083     if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
0084         return;
0085     val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
0086     val1 *= ((w->buf[0] >> 2) & 2) - 1; /* sign */
0087     val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
0088     val2 *= (w->buf[2] & 2) - 1;    /* sign */
0089     val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
0090     val3 *= ((w->buf[5] >> 2) & 2) - 1; /* sign */
0091     val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
0092     val4 *= (w->buf[7] & 2) - 1;    /* sign */
0093     val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
0094     val5 *= ((w->buf[11] >> 2) & 2) - 1;    /* sign */
0095     val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
0096     val6 *= (w->buf[13] & 2) - 1;   /* sign */
0097     val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
0098     val7 *= ((w->buf[16] >> 2) & 2) - 1;    /*sign */
0099     val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
0100     val8 *= (w->buf[18] & 2) - 1;   /*sign */
0101
0102     magic = (w->buf[21] << 4) | w->buf[22];
0103     magic_bit = (w->buf[24] & 8) >> 3;
0104     pr_debug("%4d %4d %4d %4d  %4d %4d %4d %4d (magic %2x %d)\n",
0105          val1, val2, val3, val4, val5, val6, val7, val8,
0106          magic, magic_bit);
0107
0108     input_report_abs(w->input_dev, ABS_X, val2);
0109     input_report_abs(w->input_dev, ABS_Y, val1);
0110     input_report_abs(w->input_dev, ABS_Z, val6);
0111     input_report_abs(w->input_dev, ABS_THROTTLE, val3);
0112     input_report_abs(w->input_dev, ABS_RUDDER, val4);
0113     input_report_abs(w->input_dev, ABS_MISC, val7);
0114     input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
0115 }
0116
0117 static inline int read_ack(struct pardevice *p)
0118 {
0119     return parport_read_status(p->port) & 0x40;
0120 }
0121
0122 /* falling edge, prepare to BIN value calculation */
0123 static void walkera0701_irq_handler(void *handler_data)
0124 {
0125     u64 pulse_time;
0126     struct walkera_dev *w = handler_data;
0127
0128     w->irq_time = ktime_to_ns(ktime_get());
0129     pulse_time = w->irq_time - w->irq_lasttime;
0130     w->irq_lasttime = w->irq_time;
0131
0132     /* cancel timer, if in handler or active do resync */
0133     if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
0134         w->counter = NO_SYNC;
0135         return;
0136     }
0137
0138     if (w->counter < NO_SYNC) {
0139         if (w->ack) {
0140             pulse_time -= BIN1_PULSE;
0141             w->buf[w->counter] = 8;
0142         } else {
0143             pulse_time -= BIN0_PULSE;
0144             w->buf[w->counter] = 0;
0145         }
0146         if (w->counter == 24) { /* full frame */
0147             walkera0701_parse_frame(w);
0148             w->counter = NO_SYNC;
0149             if (abs(pulse_time - SYNC_PULSE) < RESERVE) /* new frame sync */
0150                 w->counter = 0;
0151         } else {
0152             if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
0153                  && (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
0154                 pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
0155                 pulse_time = (u32) pulse_time / ANALOG_DELTA;   /* overtiping is safe, pulsetime < s32.. */
0156                 w->buf[w->counter++] |= (pulse_time & 7);
0157             } else
0158                 w->counter = NO_SYNC;
0159         }
0160     } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
0161                 RESERVE + BIN1_PULSE - BIN0_PULSE)  /* frame sync .. */
0162         w->counter = 0;
0163
0164     hrtimer_start(&w->timer, BIN_SAMPLE, HRTIMER_MODE_REL);
0165 }
0166
0167 static enum hrtimer_restart timer_handler(struct hrtimer
0168                       *handle)
0169 {
0170     struct walkera_dev *w;
0171
0172     w = container_of(handle, struct walkera_dev, timer);
0173     w->ack = read_ack(w->pardevice);
0174
0175     return HRTIMER_NORESTART;
0176 }
0177
0178 static int walkera0701_open(struct input_dev *dev)
0179 {
0180     struct walkera_dev *w = input_get_drvdata(dev);
0181
0182     if (parport_claim(w->pardevice))
0183         return -EBUSY;
0184
0185     parport_enable_irq(w->parport);
0186     return 0;
0187 }
0188
0189 static void walkera0701_close(struct input_dev *dev)
0190 {
0191     struct walkera_dev *w = input_get_drvdata(dev);
0192
0193     parport_disable_irq(w->parport);
0194     hrtimer_cancel(&w->timer);
0195
0196     parport_release(w->pardevice);
0197 }
0198
0199 static void walkera0701_attach(struct parport *pp)
0200 {
0201     struct pardev_cb walkera0701_parport_cb;
0202     struct walkera_dev *w = &w_dev;
0203
0204     if (pp->number != walkera0701_pp_no) {
0205         pr_debug("Not using parport%d.\n", pp->number);
0206         return;
0207     }
0208
0209     if (pp->irq == -1) {
0210         pr_err("parport %d does not have interrupt assigned\n",
0211             pp->number);
0212         return;
0213     }
0214
0215     w->parport = pp;
0216
0217     memset(&walkera0701_parport_cb, 0, sizeof(walkera0701_parport_cb));
0218     walkera0701_parport_cb.flags = PARPORT_FLAG_EXCL;
0219     walkera0701_parport_cb.irq_func = walkera0701_irq_handler;
0220     walkera0701_parport_cb.private = w;
0221
0222     w->pardevice = parport_register_dev_model(pp, "walkera0701",
0223                           &walkera0701_parport_cb, 0);
0224
0225     if (!w->pardevice) {
0226         pr_err("failed to register parport device\n");
0227         return;
0228     }
0229
0230     if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) {
0231         pr_err("failed to negotiate parport mode\n");
0232         goto err_unregister_device;
0233     }
0234
0235     hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
0236     w->timer.function = timer_handler;
0237
0238     w->input_dev = input_allocate_device();
0239     if (!w->input_dev) {
0240         pr_err("failed to allocate input device\n");
0241         goto err_unregister_device;
0242     }
0243
0244     input_set_drvdata(w->input_dev, w);
0245     w->input_dev->name = "Walkera WK-0701 TX";
0246     w->input_dev->phys = w->parport->name;
0247     w->input_dev->id.bustype = BUS_PARPORT;
0248
0249     /* TODO what id vendor/product/version ? */
0250     w->input_dev->id.vendor = 0x0001;
0251     w->input_dev->id.product = 0x0001;
0252     w->input_dev->id.version = 0x0100;
0253     w->input_dev->dev.parent = w->parport->dev;
0254     w->input_dev->open = walkera0701_open;
0255     w->input_dev->close = walkera0701_close;
0256
0257     w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
0258     w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
0259
0260     input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
0261     input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
0262     input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
0263     input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
0264     input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
0265     input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
0266
0267     if (input_register_device(w->input_dev)) {
0268         pr_err("failed to register input device\n");
0269         goto err_free_input_dev;
0270     }
0271
0272     return;
0273
0274 err_free_input_dev:
0275     input_free_device(w->input_dev);
0276 err_unregister_device:
0277     parport_unregister_device(w->pardevice);
0278 }
0279
0280 static void walkera0701_detach(struct parport *port)
0281 {
0282     struct walkera_dev *w = &w_dev;
0283
0284     if (!w->pardevice || w->parport->number != port->number)
0285         return;
0286
0287     input_unregister_device(w->input_dev);
0288     parport_unregister_device(w->pardevice);
0289     w->parport = NULL;
0290 }
0291
0292 static struct parport_driver walkera0701_parport_driver = {
0293     .name = "walkera0701",
0294     .match_port = walkera0701_attach,
0295     .detach = walkera0701_detach,
0296     .devmodel = true,
0297 };
0298
0299 static int __init walkera0701_init(void)
0300 {
0301     return parport_register_driver(&walkera0701_parport_driver);
0302 }
0303
0304 static void __exit walkera0701_exit(void)
0305 {
0306     parport_unregister_driver(&walkera0701_parport_driver);
0307 }
0308
0309 module_init(walkera0701_init);
0310 module_exit(walkera0701_exit);