walkera0701.c 8.5 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Parallel port to Walkera WK-0701 TX joystick
  4. *
  5. * Copyright (c) 2008 Peter Popovec
  6. *
  7. * More about driver: <file:Documentation/input/devices/walkera0701.rst>
  8. */
  9. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10. #define RESERVE 20000
  11. #define SYNC_PULSE 1306000
  12. #define BIN0_PULSE 288000
  13. #define BIN1_PULSE 438000
  14. #define ANALOG_MIN_PULSE 318000
  15. #define ANALOG_MAX_PULSE 878000
  16. #define ANALOG_DELTA 80000
  17. #define BIN_SAMPLE ((BIN0_PULSE + BIN1_PULSE) / 2)
  18. #define NO_SYNC 25
  19. #include <linux/kernel.h>
  20. #include <linux/module.h>
  21. #include <linux/parport.h>
  22. #include <linux/input.h>
  23. #include <linux/hrtimer.h>
  24. MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
  25. MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
  26. MODULE_LICENSE("GPL");
  27. static unsigned int walkera0701_pp_no;
  28. module_param_named(port, walkera0701_pp_no, int, 0);
  29. MODULE_PARM_DESC(port,
  30. "Parallel port adapter for Walkera WK-0701 TX (default is 0)");
  31. /*
  32. * For now, only one device is supported, if somebody need more devices, code
  33. * can be expanded, one struct walkera_dev per device must be allocated and
  34. * set up by walkera0701_connect (release of device by walkera0701_disconnect)
  35. */
  36. struct walkera_dev {
  37. unsigned char buf[25];
  38. u64 irq_time, irq_lasttime;
  39. int counter;
  40. int ack;
  41. struct input_dev *input_dev;
  42. struct hrtimer timer;
  43. struct parport *parport;
  44. struct pardevice *pardevice;
  45. };
  46. static struct walkera_dev w_dev;
  47. static inline void walkera0701_parse_frame(struct walkera_dev *w)
  48. {
  49. int i;
  50. int val1, val2, val3, val4, val5, val6, val7, val8;
  51. int magic, magic_bit;
  52. int crc1, crc2;
  53. for (crc1 = crc2 = i = 0; i < 10; i++) {
  54. crc1 += w->buf[i] & 7;
  55. crc2 += (w->buf[i] & 8) >> 3;
  56. }
  57. if ((w->buf[10] & 7) != (crc1 & 7))
  58. return;
  59. if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  60. return;
  61. for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
  62. crc1 += w->buf[i] & 7;
  63. crc2 += (w->buf[i] & 8) >> 3;
  64. }
  65. if ((w->buf[23] & 7) != (crc1 & 7))
  66. return;
  67. if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
  68. return;
  69. val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
  70. val1 *= ((w->buf[0] >> 2) & 2) - 1; /* sign */
  71. val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
  72. val2 *= (w->buf[2] & 2) - 1; /* sign */
  73. val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
  74. val3 *= ((w->buf[5] >> 2) & 2) - 1; /* sign */
  75. val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
  76. val4 *= (w->buf[7] & 2) - 1; /* sign */
  77. val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
  78. val5 *= ((w->buf[11] >> 2) & 2) - 1; /* sign */
  79. val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
  80. val6 *= (w->buf[13] & 2) - 1; /* sign */
  81. val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
  82. val7 *= ((w->buf[16] >> 2) & 2) - 1; /*sign */
  83. val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
  84. val8 *= (w->buf[18] & 2) - 1; /*sign */
  85. magic = (w->buf[21] << 4) | w->buf[22];
  86. magic_bit = (w->buf[24] & 8) >> 3;
  87. pr_debug("%4d %4d %4d %4d %4d %4d %4d %4d (magic %2x %d)\n",
  88. val1, val2, val3, val4, val5, val6, val7, val8,
  89. magic, magic_bit);
  90. input_report_abs(w->input_dev, ABS_X, val2);
  91. input_report_abs(w->input_dev, ABS_Y, val1);
  92. input_report_abs(w->input_dev, ABS_Z, val6);
  93. input_report_abs(w->input_dev, ABS_THROTTLE, val3);
  94. input_report_abs(w->input_dev, ABS_RUDDER, val4);
  95. input_report_abs(w->input_dev, ABS_MISC, val7);
  96. input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
  97. }
  98. static inline int read_ack(struct pardevice *p)
  99. {
  100. return parport_read_status(p->port) & 0x40;
  101. }
  102. /* falling edge, prepare to BIN value calculation */
  103. static void walkera0701_irq_handler(void *handler_data)
  104. {
  105. u64 pulse_time;
  106. struct walkera_dev *w = handler_data;
  107. w->irq_time = ktime_to_ns(ktime_get());
  108. pulse_time = w->irq_time - w->irq_lasttime;
  109. w->irq_lasttime = w->irq_time;
  110. /* cancel timer, if in handler or active do resync */
  111. if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
  112. w->counter = NO_SYNC;
  113. return;
  114. }
  115. if (w->counter < NO_SYNC) {
  116. if (w->ack) {
  117. pulse_time -= BIN1_PULSE;
  118. w->buf[w->counter] = 8;
  119. } else {
  120. pulse_time -= BIN0_PULSE;
  121. w->buf[w->counter] = 0;
  122. }
  123. if (w->counter == 24) { /* full frame */
  124. walkera0701_parse_frame(w);
  125. w->counter = NO_SYNC;
  126. if (abs(pulse_time - SYNC_PULSE) < RESERVE) /* new frame sync */
  127. w->counter = 0;
  128. } else {
  129. if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
  130. && (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
  131. pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
  132. pulse_time = (u32) pulse_time / ANALOG_DELTA; /* overtiping is safe, pulsetime < s32.. */
  133. w->buf[w->counter++] |= (pulse_time & 7);
  134. } else
  135. w->counter = NO_SYNC;
  136. }
  137. } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
  138. RESERVE + BIN1_PULSE - BIN0_PULSE) /* frame sync .. */
  139. w->counter = 0;
  140. hrtimer_start(&w->timer, BIN_SAMPLE, HRTIMER_MODE_REL);
  141. }
  142. static enum hrtimer_restart timer_handler(struct hrtimer
  143. *handle)
  144. {
  145. struct walkera_dev *w;
  146. w = container_of(handle, struct walkera_dev, timer);
  147. w->ack = read_ack(w->pardevice);
  148. return HRTIMER_NORESTART;
  149. }
  150. static int walkera0701_open(struct input_dev *dev)
  151. {
  152. struct walkera_dev *w = input_get_drvdata(dev);
  153. if (parport_claim(w->pardevice))
  154. return -EBUSY;
  155. parport_enable_irq(w->parport);
  156. return 0;
  157. }
  158. static void walkera0701_close(struct input_dev *dev)
  159. {
  160. struct walkera_dev *w = input_get_drvdata(dev);
  161. parport_disable_irq(w->parport);
  162. hrtimer_cancel(&w->timer);
  163. parport_release(w->pardevice);
  164. }
  165. static void walkera0701_attach(struct parport *pp)
  166. {
  167. struct pardev_cb walkera0701_parport_cb;
  168. struct walkera_dev *w = &w_dev;
  169. if (pp->number != walkera0701_pp_no) {
  170. pr_debug("Not using parport%d.\n", pp->number);
  171. return;
  172. }
  173. if (pp->irq == -1) {
  174. pr_err("parport %d does not have interrupt assigned\n",
  175. pp->number);
  176. return;
  177. }
  178. w->parport = pp;
  179. memset(&walkera0701_parport_cb, 0, sizeof(walkera0701_parport_cb));
  180. walkera0701_parport_cb.flags = PARPORT_FLAG_EXCL;
  181. walkera0701_parport_cb.irq_func = walkera0701_irq_handler;
  182. walkera0701_parport_cb.private = w;
  183. w->pardevice = parport_register_dev_model(pp, "walkera0701",
  184. &walkera0701_parport_cb, 0);
  185. if (!w->pardevice) {
  186. pr_err("failed to register parport device\n");
  187. return;
  188. }
  189. if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) {
  190. pr_err("failed to negotiate parport mode\n");
  191. goto err_unregister_device;
  192. }
  193. hrtimer_init(&w->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
  194. w->timer.function = timer_handler;
  195. w->input_dev = input_allocate_device();
  196. if (!w->input_dev) {
  197. pr_err("failed to allocate input device\n");
  198. goto err_unregister_device;
  199. }
  200. input_set_drvdata(w->input_dev, w);
  201. w->input_dev->name = "Walkera WK-0701 TX";
  202. w->input_dev->phys = w->parport->name;
  203. w->input_dev->id.bustype = BUS_PARPORT;
  204. /* TODO what id vendor/product/version ? */
  205. w->input_dev->id.vendor = 0x0001;
  206. w->input_dev->id.product = 0x0001;
  207. w->input_dev->id.version = 0x0100;
  208. w->input_dev->dev.parent = w->parport->dev;
  209. w->input_dev->open = walkera0701_open;
  210. w->input_dev->close = walkera0701_close;
  211. w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
  212. w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
  213. input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
  214. input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
  215. input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
  216. input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
  217. input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
  218. input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
  219. if (input_register_device(w->input_dev)) {
  220. pr_err("failed to register input device\n");
  221. goto err_free_input_dev;
  222. }
  223. return;
  224. err_free_input_dev:
  225. input_free_device(w->input_dev);
  226. err_unregister_device:
  227. parport_unregister_device(w->pardevice);
  228. }
  229. static void walkera0701_detach(struct parport *port)
  230. {
  231. struct walkera_dev *w = &w_dev;
  232. if (!w->pardevice || w->parport->number != port->number)
  233. return;
  234. input_unregister_device(w->input_dev);
  235. parport_unregister_device(w->pardevice);
  236. w->parport = NULL;
  237. }
  238. static struct parport_driver walkera0701_parport_driver = {
  239. .name = "walkera0701",
  240. .match_port = walkera0701_attach,
  241. .detach = walkera0701_detach,
  242. .devmodel = true,
  243. };
  244. static int __init walkera0701_init(void)
  245. {
  246. return parport_register_driver(&walkera0701_parport_driver);
  247. }
  248. static void __exit walkera0701_exit(void)
  249. {
  250. parport_unregister_driver(&walkera0701_parport_driver);
  251. }
  252. module_init(walkera0701_init);
  253. module_exit(walkera0701_exit);