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 hrtimer_cancel(&w->timer); 200 } 201 202 static int walkera0701_connect(struct walkera_dev *w, int parport) 203 { 204 int err = -ENODEV; 205 206 w->parport = parport_find_number(parport); 207 if (w->parport == NULL) 208 return -ENODEV; 209 210 if (w->parport->irq == -1) { 211 printk(KERN_ERR "walkera0701: parport without interrupt\n"); 212 goto init_err; 213 } 214 215 err = -EBUSY; 216 w->pardevice = parport_register_device(w->parport, "walkera0701", 217 NULL, NULL, walkera0701_irq_handler, 218 PARPORT_DEV_EXCL, w); 219 if (!w->pardevice) 220 goto init_err; 221 222 if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) 223 goto init_err1; 224 225 if (parport_claim(w->pardevice)) 226 goto init_err1; 227 228 hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 229 w->timer.function = timer_handler; 230 231 w->input_dev = input_allocate_device(); 232 if (!w->input_dev) 233 goto init_err2; 234 235 input_set_drvdata(w->input_dev, w); 236 w->input_dev->name = "Walkera WK-0701 TX"; 237 w->input_dev->phys = w->parport->name; 238 w->input_dev->id.bustype = BUS_PARPORT; 239 240 /* TODO what id vendor/product/version ? */ 241 w->input_dev->id.vendor = 0x0001; 242 w->input_dev->id.product = 0x0001; 243 w->input_dev->id.version = 0x0100; 244 w->input_dev->open = walkera0701_open; 245 w->input_dev->close = walkera0701_close; 246 247 w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY); 248 w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN); 249 250 input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0); 251 input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0); 252 input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0); 253 input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0); 254 input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0); 255 input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0); 256 257 err = input_register_device(w->input_dev); 258 if (err) 259 goto init_err3; 260 261 return 0; 262 263 init_err3: 264 input_free_device(w->input_dev); 265 init_err2: 266 parport_release(w->pardevice); 267 init_err1: 268 parport_unregister_device(w->pardevice); 269 init_err: 270 parport_put_port(w->parport); 271 return err; 272 } 273 274 static void walkera0701_disconnect(struct walkera_dev *w) 275 { 276 input_unregister_device(w->input_dev); 277 parport_release(w->pardevice); 278 parport_unregister_device(w->pardevice); 279 parport_put_port(w->parport); 280 } 281 282 static int __init walkera0701_init(void) 283 { 284 return walkera0701_connect(&w_dev, walkera0701_pp_no); 285 } 286 287 static void __exit walkera0701_exit(void) 288 { 289 walkera0701_disconnect(&w_dev); 290 } 291 292 module_init(walkera0701_init); 293 module_exit(walkera0701_exit); 294