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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
36MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
37MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
38MODULE_LICENSE("GPL");
39
40static unsigned int walkera0701_pp_no;
41module_param_named(port, walkera0701_pp_no, int, 0);
42MODULE_PARM_DESC(port,
43 "Parallel port adapter for Walkera WK-0701 TX (default is 0)");
44
45
46
47
48
49
50
51struct 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
64static struct walkera_dev w_dev;
65
66static 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;
90 val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
91 val2 *= (w->buf[2] & 2) - 1;
92 val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
93 val3 *= ((w->buf[5] >> 2) & 2) - 1;
94 val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
95 val4 *= (w->buf[7] & 2) - 1;
96 val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
97 val5 *= ((w->buf[11] >> 2) & 2) - 1;
98 val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
99 val6 *= (w->buf[13] & 2) - 1;
100 val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
101 val7 *= ((w->buf[16] >> 2) & 2) - 1;
102 val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
103 val8 *= (w->buf[18] & 2) - 1;
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
125static inline int read_ack(struct pardevice *p)
126{
127 return parport_read_status(p->port) & 0x40;
128}
129
130
131static 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
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) {
155 walkera0701_parse_frame(w);
156 w->counter = NO_SYNC;
157 if (abs(pulse_time - SYNC_PULSE) < RESERVE)
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;
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)
170 w->counter = 0;
171
172 hrtimer_start(&w->timer, ktime_set(0, BIN_SAMPLE), HRTIMER_MODE_REL);
173}
174
175static 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
186static 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
194static 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
201static 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
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
272static 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
281static int __init walkera0701_init(void)
282{
283 return walkera0701_connect(&w_dev, walkera0701_pp_no);
284}
285
286static void __exit walkera0701_exit(void)
287{
288 walkera0701_disconnect(&w_dev);
289}
290
291module_init(walkera0701_init);
292module_exit(walkera0701_exit);
293
