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 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, ktime_set(0, 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 int walkera0701_connect(struct walkera_dev *w, int parport) 204 { 205 int error; 206 207 w->parport = parport_find_number(parport); 208 if (!w->parport) { 209 pr_err("parport %d does not exist\n", parport); 210 return -ENODEV; 211 } 212 213 if (w->parport->irq == -1) { 214 pr_err("parport %d does not have interrupt assigned\n", 215 parport); 216 error = -EINVAL; 217 goto err_put_parport; 218 } 219 220 w->pardevice = parport_register_device(w->parport, "walkera0701", 221 NULL, NULL, walkera0701_irq_handler, 222 PARPORT_DEV_EXCL, w); 223 if (!w->pardevice) { 224 pr_err("failed to register parport device\n"); 225 error = -EIO; 226 goto err_put_parport; 227 } 228 229 if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) { 230 pr_err("failed to negotiate parport mode\n"); 231 error = -EIO; 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 error = -ENOMEM; 242 goto err_unregister_device; 243 } 244 245 input_set_drvdata(w->input_dev, w); 246 w->input_dev->name = "Walkera WK-0701 TX"; 247 w->input_dev->phys = w->parport->name; 248 w->input_dev->id.bustype = BUS_PARPORT; 249 250 /* TODO what id vendor/product/version ? */ 251 w->input_dev->id.vendor = 0x0001; 252 w->input_dev->id.product = 0x0001; 253 w->input_dev->id.version = 0x0100; 254 w->input_dev->dev.parent = w->parport->dev; 255 w->input_dev->open = walkera0701_open; 256 w->input_dev->close = walkera0701_close; 257 258 w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY); 259 w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN); 260 261 input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0); 262 input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0); 263 input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0); 264 input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0); 265 input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0); 266 input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0); 267 268 error = input_register_device(w->input_dev); 269 if (error) { 270 pr_err("failed to register input device\n"); 271 goto err_free_input_dev; 272 } 273 274 return 0; 275 276 err_free_input_dev: 277 input_free_device(w->input_dev); 278 err_unregister_device: 279 parport_unregister_device(w->pardevice); 280 err_put_parport: 281 parport_put_port(w->parport); 282 return error; 283 } 284 285 static void walkera0701_disconnect(struct walkera_dev *w) 286 { 287 input_unregister_device(w->input_dev); 288 parport_unregister_device(w->pardevice); 289 parport_put_port(w->parport); 290 } 291 292 static int __init walkera0701_init(void) 293 { 294 return walkera0701_connect(&w_dev, walkera0701_pp_no); 295 } 296 297 static void __exit walkera0701_exit(void) 298 { 299 walkera0701_disconnect(&w_dev); 300 } 301 302 module_init(walkera0701_init); 303 module_exit(walkera0701_exit); 304