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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
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#define RESERVE 20000
14#define SYNC_PULSE 1306000
15#define BIN0_PULSE 288000
16#define BIN1_PULSE 438000
17
18#define ANALOG_MIN_PULSE 318000
19#define ANALOG_MAX_PULSE 878000
20#define ANALOG_DELTA 80000
21
22#define BIN_SAMPLE ((BIN0_PULSE + BIN1_PULSE) / 2)
23
24#define NO_SYNC 25
25
26#include <linux/kernel.h>
27#include <linux/module.h>
28#include <linux/parport.h>
29#include <linux/input.h>
30#include <linux/hrtimer.h>
31
32MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
33MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
34MODULE_LICENSE("GPL");
35
36static unsigned int walkera0701_pp_no;
37module_param_named(port, walkera0701_pp_no, int, 0);
38MODULE_PARM_DESC(port,
39 "Parallel port adapter for Walkera WK-0701 TX (default is 0)");
40
41/*
42 * For now, only one device is supported, if somebody need more devices, code
43 * can be expanded, one struct walkera_dev per device must be allocated and
44 * set up by walkera0701_connect (release of device by walkera0701_disconnect)
45 */
46
47struct walkera_dev {
48 unsigned char buf[25];
49 u64 irq_time, irq_lasttime;
50 int counter;
51 int ack;
52
53 struct input_dev *input_dev;
54 struct hrtimer timer;
55
56 struct parport *parport;
57 struct pardevice *pardevice;
58};
59
60static struct walkera_dev w_dev;
61
62static inline void walkera0701_parse_frame(struct walkera_dev *w)
63{
64 int i;
65 int val1, val2, val3, val4, val5, val6, val7, val8;
66 int magic, magic_bit;
67 int crc1, crc2;
68
69 for (crc1 = crc2 = i = 0; i < 10; i++) {
70 crc1 += w->buf[i] & 7;
71 crc2 += (w->buf[i] & 8) >> 3;
72 }
73 if ((w->buf[10] & 7) != (crc1 & 7))
74 return;
75 if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
76 return;
77 for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
78 crc1 += w->buf[i] & 7;
79 crc2 += (w->buf[i] & 8) >> 3;
80 }
81 if ((w->buf[23] & 7) != (crc1 & 7))
82 return;
83 if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
84 return;
85 val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
86 val1 *= ((w->buf[0] >> 2) & 2) - 1; /* sign */
87 val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
88 val2 *= (w->buf[2] & 2) - 1; /* sign */
89 val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
90 val3 *= ((w->buf[5] >> 2) & 2) - 1; /* sign */
91 val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
92 val4 *= (w->buf[7] & 2) - 1; /* sign */
93 val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
94 val5 *= ((w->buf[11] >> 2) & 2) - 1; /* sign */
95 val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
96 val6 *= (w->buf[13] & 2) - 1; /* sign */
97 val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
98 val7 *= ((w->buf[16] >> 2) & 2) - 1; /*sign */
99 val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
100 val8 *= (w->buf[18] & 2) - 1; /*sign */
101
102 magic = (w->buf[21] << 4) | w->buf[22];
103 magic_bit = (w->buf[24] & 8) >> 3;
104 pr_debug("%4d %4d %4d %4d %4d %4d %4d %4d (magic %2x %d)\n",
105 val1, val2, val3, val4, val5, val6, val7, val8,
106 magic, magic_bit);
107
108 input_report_abs(w->input_dev, ABS_X, val2);
109 input_report_abs(w->input_dev, ABS_Y, val1);
110 input_report_abs(w->input_dev, ABS_Z, val6);
111 input_report_abs(w->input_dev, ABS_THROTTLE, val3);
112 input_report_abs(w->input_dev, ABS_RUDDER, val4);
113 input_report_abs(w->input_dev, ABS_MISC, val7);
114 input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
115}
116
117static inline int read_ack(struct pardevice *p)
118{
119 return parport_read_status(p->port) & 0x40;
120}
121
122/* falling edge, prepare to BIN value calculation */
123static void walkera0701_irq_handler(void *handler_data)
124{
125 u64 pulse_time;
126 struct walkera_dev *w = handler_data;
127
128 w->irq_time = ktime_to_ns(ktime_get());
129 pulse_time = w->irq_time - w->irq_lasttime;
130 w->irq_lasttime = w->irq_time;
131
132 /* cancel timer, if in handler or active do resync */
133 if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
134 w->counter = NO_SYNC;
135 return;
136 }
137
138 if (w->counter < NO_SYNC) {
139 if (w->ack) {
140 pulse_time -= BIN1_PULSE;
141 w->buf[w->counter] = 8;
142 } else {
143 pulse_time -= BIN0_PULSE;
144 w->buf[w->counter] = 0;
145 }
146 if (w->counter == 24) { /* full frame */
147 walkera0701_parse_frame(w);
148 w->counter = NO_SYNC;
149 if (abs(pulse_time - SYNC_PULSE) < RESERVE) /* new frame sync */
150 w->counter = 0;
151 } else {
152 if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
153 && (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
154 pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
155 pulse_time = (u32) pulse_time / ANALOG_DELTA; /* overtiping is safe, pulsetime < s32.. */
156 w->buf[w->counter++] |= (pulse_time & 7);
157 } else
158 w->counter = NO_SYNC;
159 }
160 } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
161 RESERVE + BIN1_PULSE - BIN0_PULSE) /* frame sync .. */
162 w->counter = 0;
163
164 hrtimer_start(&w->timer, BIN_SAMPLE, HRTIMER_MODE_REL);
165}
166
167static enum hrtimer_restart timer_handler(struct hrtimer
168 *handle)
169{
170 struct walkera_dev *w;
171
172 w = container_of(handle, struct walkera_dev, timer);
173 w->ack = read_ack(w->pardevice);
174
175 return HRTIMER_NORESTART;
176}
177
178static int walkera0701_open(struct input_dev *dev)
179{
180 struct walkera_dev *w = input_get_drvdata(dev);
181
182 if (parport_claim(w->pardevice))
183 return -EBUSY;
184
185 parport_enable_irq(w->parport);
186 return 0;
187}
188
189static void walkera0701_close(struct input_dev *dev)
190{
191 struct walkera_dev *w = input_get_drvdata(dev);
192
193 parport_disable_irq(w->parport);
194 hrtimer_cancel(&w->timer);
195
196 parport_release(w->pardevice);
197}
198
199static void walkera0701_attach(struct parport *pp)
200{
201 struct pardev_cb walkera0701_parport_cb;
202 struct walkera_dev *w = &w_dev;
203
204 if (pp->number != walkera0701_pp_no) {
205 pr_debug("Not using parport%d.\n", pp->number);
206 return;
207 }
208
209 if (pp->irq == -1) {
210 pr_err("parport %d does not have interrupt assigned\n",
211 pp->number);
212 return;
213 }
214
215 w->parport = pp;
216
217 memset(&walkera0701_parport_cb, 0, sizeof(walkera0701_parport_cb));
218 walkera0701_parport_cb.flags = PARPORT_FLAG_EXCL;
219 walkera0701_parport_cb.irq_func = walkera0701_irq_handler;
220 walkera0701_parport_cb.private = w;
221
222 w->pardevice = parport_register_dev_model(pp, "walkera0701",
223 &walkera0701_parport_cb, 0);
224
225 if (!w->pardevice) {
226 pr_err("failed to register parport device\n");
227 return;
228 }
229
230 if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) {
231 pr_err("failed to negotiate parport mode\n");
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 goto err_unregister_device;
242 }
243
244 input_set_drvdata(w->input_dev, w);
245 w->input_dev->name = "Walkera WK-0701 TX";
246 w->input_dev->phys = w->parport->name;
247 w->input_dev->id.bustype = BUS_PARPORT;
248
249 /* TODO what id vendor/product/version ? */
250 w->input_dev->id.vendor = 0x0001;
251 w->input_dev->id.product = 0x0001;
252 w->input_dev->id.version = 0x0100;
253 w->input_dev->dev.parent = w->parport->dev;
254 w->input_dev->open = walkera0701_open;
255 w->input_dev->close = walkera0701_close;
256
257 w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
258 w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
259
260 input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
261 input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
262 input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
263 input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
264 input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
265 input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
266
267 if (input_register_device(w->input_dev)) {
268 pr_err("failed to register input device\n");
269 goto err_free_input_dev;
270 }
271
272 return;
273
274err_free_input_dev:
275 input_free_device(w->input_dev);
276err_unregister_device:
277 parport_unregister_device(w->pardevice);
278}
279
280static void walkera0701_detach(struct parport *port)
281{
282 struct walkera_dev *w = &w_dev;
283
284 if (!w->pardevice || w->parport->number != port->number)
285 return;
286
287 input_unregister_device(w->input_dev);
288 parport_unregister_device(w->pardevice);
289 w->parport = NULL;
290}
291
292static struct parport_driver walkera0701_parport_driver = {
293 .name = "walkera0701",
294 .match_port = walkera0701_attach,
295 .detach = walkera0701_detach,
296 .devmodel = true,
297};
298
299static int __init walkera0701_init(void)
300{
301 return parport_register_driver(&walkera0701_parport_driver);
302}
303
304static void __exit walkera0701_exit(void)
305{
306 parport_unregister_driver(&walkera0701_parport_driver);
307}
308
309module_init(walkera0701_init);
310module_exit(walkera0701_exit);
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
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#define RESERVE 20000
14#define SYNC_PULSE 1306000
15#define BIN0_PULSE 288000
16#define BIN1_PULSE 438000
17
18#define ANALOG_MIN_PULSE 318000
19#define ANALOG_MAX_PULSE 878000
20#define ANALOG_DELTA 80000
21
22#define BIN_SAMPLE ((BIN0_PULSE + BIN1_PULSE) / 2)
23
24#define NO_SYNC 25
25
26#include <linux/kernel.h>
27#include <linux/module.h>
28#include <linux/parport.h>
29#include <linux/input.h>
30#include <linux/hrtimer.h>
31
32MODULE_AUTHOR("Peter Popovec <popovec@fei.tuke.sk>");
33MODULE_DESCRIPTION("Walkera WK-0701 TX as joystick");
34MODULE_LICENSE("GPL");
35
36static unsigned int walkera0701_pp_no;
37module_param_named(port, walkera0701_pp_no, int, 0);
38MODULE_PARM_DESC(port,
39 "Parallel port adapter for Walkera WK-0701 TX (default is 0)");
40
41/*
42 * For now, only one device is supported, if somebody need more devices, code
43 * can be expanded, one struct walkera_dev per device must be allocated and
44 * set up by walkera0701_connect (release of device by walkera0701_disconnect)
45 */
46
47struct walkera_dev {
48 unsigned char buf[25];
49 u64 irq_time, irq_lasttime;
50 int counter;
51 int ack;
52
53 struct input_dev *input_dev;
54 struct hrtimer timer;
55
56 struct parport *parport;
57 struct pardevice *pardevice;
58};
59
60static struct walkera_dev w_dev;
61
62static inline void walkera0701_parse_frame(struct walkera_dev *w)
63{
64 int i;
65 int val1, val2, val3, val4, val5, val6, val7, val8;
66 int magic, magic_bit;
67 int crc1, crc2;
68
69 for (crc1 = crc2 = i = 0; i < 10; i++) {
70 crc1 += w->buf[i] & 7;
71 crc2 += (w->buf[i] & 8) >> 3;
72 }
73 if ((w->buf[10] & 7) != (crc1 & 7))
74 return;
75 if (((w->buf[10] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
76 return;
77 for (crc1 = crc2 = 0, i = 11; i < 23; i++) {
78 crc1 += w->buf[i] & 7;
79 crc2 += (w->buf[i] & 8) >> 3;
80 }
81 if ((w->buf[23] & 7) != (crc1 & 7))
82 return;
83 if (((w->buf[23] & 8) >> 3) != (((crc1 >> 3) + crc2) & 1))
84 return;
85 val1 = ((w->buf[0] & 7) * 256 + w->buf[1] * 16 + w->buf[2]) >> 2;
86 val1 *= ((w->buf[0] >> 2) & 2) - 1; /* sign */
87 val2 = (w->buf[2] & 1) << 8 | (w->buf[3] << 4) | w->buf[4];
88 val2 *= (w->buf[2] & 2) - 1; /* sign */
89 val3 = ((w->buf[5] & 7) * 256 + w->buf[6] * 16 + w->buf[7]) >> 2;
90 val3 *= ((w->buf[5] >> 2) & 2) - 1; /* sign */
91 val4 = (w->buf[7] & 1) << 8 | (w->buf[8] << 4) | w->buf[9];
92 val4 *= (w->buf[7] & 2) - 1; /* sign */
93 val5 = ((w->buf[11] & 7) * 256 + w->buf[12] * 16 + w->buf[13]) >> 2;
94 val5 *= ((w->buf[11] >> 2) & 2) - 1; /* sign */
95 val6 = (w->buf[13] & 1) << 8 | (w->buf[14] << 4) | w->buf[15];
96 val6 *= (w->buf[13] & 2) - 1; /* sign */
97 val7 = ((w->buf[16] & 7) * 256 + w->buf[17] * 16 + w->buf[18]) >> 2;
98 val7 *= ((w->buf[16] >> 2) & 2) - 1; /*sign */
99 val8 = (w->buf[18] & 1) << 8 | (w->buf[19] << 4) | w->buf[20];
100 val8 *= (w->buf[18] & 2) - 1; /*sign */
101
102 magic = (w->buf[21] << 4) | w->buf[22];
103 magic_bit = (w->buf[24] & 8) >> 3;
104 pr_debug("%4d %4d %4d %4d %4d %4d %4d %4d (magic %2x %d)\n",
105 val1, val2, val3, val4, val5, val6, val7, val8,
106 magic, magic_bit);
107
108 input_report_abs(w->input_dev, ABS_X, val2);
109 input_report_abs(w->input_dev, ABS_Y, val1);
110 input_report_abs(w->input_dev, ABS_Z, val6);
111 input_report_abs(w->input_dev, ABS_THROTTLE, val3);
112 input_report_abs(w->input_dev, ABS_RUDDER, val4);
113 input_report_abs(w->input_dev, ABS_MISC, val7);
114 input_report_key(w->input_dev, BTN_GEAR_DOWN, val5 > 0);
115}
116
117static inline int read_ack(struct pardevice *p)
118{
119 return parport_read_status(p->port) & 0x40;
120}
121
122/* falling edge, prepare to BIN value calculation */
123static void walkera0701_irq_handler(void *handler_data)
124{
125 u64 pulse_time;
126 struct walkera_dev *w = handler_data;
127
128 w->irq_time = ktime_to_ns(ktime_get());
129 pulse_time = w->irq_time - w->irq_lasttime;
130 w->irq_lasttime = w->irq_time;
131
132 /* cancel timer, if in handler or active do resync */
133 if (unlikely(0 != hrtimer_try_to_cancel(&w->timer))) {
134 w->counter = NO_SYNC;
135 return;
136 }
137
138 if (w->counter < NO_SYNC) {
139 if (w->ack) {
140 pulse_time -= BIN1_PULSE;
141 w->buf[w->counter] = 8;
142 } else {
143 pulse_time -= BIN0_PULSE;
144 w->buf[w->counter] = 0;
145 }
146 if (w->counter == 24) { /* full frame */
147 walkera0701_parse_frame(w);
148 w->counter = NO_SYNC;
149 if (abs(pulse_time - SYNC_PULSE) < RESERVE) /* new frame sync */
150 w->counter = 0;
151 } else {
152 if ((pulse_time > (ANALOG_MIN_PULSE - RESERVE)
153 && (pulse_time < (ANALOG_MAX_PULSE + RESERVE)))) {
154 pulse_time -= (ANALOG_MIN_PULSE - RESERVE);
155 pulse_time = (u32) pulse_time / ANALOG_DELTA; /* overtiping is safe, pulsetime < s32.. */
156 w->buf[w->counter++] |= (pulse_time & 7);
157 } else
158 w->counter = NO_SYNC;
159 }
160 } else if (abs(pulse_time - SYNC_PULSE - BIN0_PULSE) <
161 RESERVE + BIN1_PULSE - BIN0_PULSE) /* frame sync .. */
162 w->counter = 0;
163
164 hrtimer_start(&w->timer, BIN_SAMPLE, HRTIMER_MODE_REL);
165}
166
167static enum hrtimer_restart timer_handler(struct hrtimer
168 *handle)
169{
170 struct walkera_dev *w;
171
172 w = container_of(handle, struct walkera_dev, timer);
173 w->ack = read_ack(w->pardevice);
174
175 return HRTIMER_NORESTART;
176}
177
178static int walkera0701_open(struct input_dev *dev)
179{
180 struct walkera_dev *w = input_get_drvdata(dev);
181
182 if (parport_claim(w->pardevice))
183 return -EBUSY;
184
185 parport_enable_irq(w->parport);
186 return 0;
187}
188
189static void walkera0701_close(struct input_dev *dev)
190{
191 struct walkera_dev *w = input_get_drvdata(dev);
192
193 parport_disable_irq(w->parport);
194 hrtimer_cancel(&w->timer);
195
196 parport_release(w->pardevice);
197}
198
199static void walkera0701_attach(struct parport *pp)
200{
201 struct pardev_cb walkera0701_parport_cb;
202 struct walkera_dev *w = &w_dev;
203
204 if (pp->number != walkera0701_pp_no) {
205 pr_debug("Not using parport%d.\n", pp->number);
206 return;
207 }
208
209 if (pp->irq == -1) {
210 pr_err("parport %d does not have interrupt assigned\n",
211 pp->number);
212 return;
213 }
214
215 w->parport = pp;
216
217 memset(&walkera0701_parport_cb, 0, sizeof(walkera0701_parport_cb));
218 walkera0701_parport_cb.flags = PARPORT_FLAG_EXCL;
219 walkera0701_parport_cb.irq_func = walkera0701_irq_handler;
220 walkera0701_parport_cb.private = w;
221
222 w->pardevice = parport_register_dev_model(pp, "walkera0701",
223 &walkera0701_parport_cb, 0);
224
225 if (!w->pardevice) {
226 pr_err("failed to register parport device\n");
227 return;
228 }
229
230 if (parport_negotiate(w->pardevice->port, IEEE1284_MODE_COMPAT)) {
231 pr_err("failed to negotiate parport mode\n");
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 goto err_unregister_device;
242 }
243
244 input_set_drvdata(w->input_dev, w);
245 w->input_dev->name = "Walkera WK-0701 TX";
246 w->input_dev->phys = w->parport->name;
247 w->input_dev->id.bustype = BUS_PARPORT;
248
249 /* TODO what id vendor/product/version ? */
250 w->input_dev->id.vendor = 0x0001;
251 w->input_dev->id.product = 0x0001;
252 w->input_dev->id.version = 0x0100;
253 w->input_dev->dev.parent = w->parport->dev;
254 w->input_dev->open = walkera0701_open;
255 w->input_dev->close = walkera0701_close;
256
257 w->input_dev->evbit[0] = BIT(EV_ABS) | BIT_MASK(EV_KEY);
258 w->input_dev->keybit[BIT_WORD(BTN_GEAR_DOWN)] = BIT_MASK(BTN_GEAR_DOWN);
259
260 input_set_abs_params(w->input_dev, ABS_X, -512, 512, 0, 0);
261 input_set_abs_params(w->input_dev, ABS_Y, -512, 512, 0, 0);
262 input_set_abs_params(w->input_dev, ABS_Z, -512, 512, 0, 0);
263 input_set_abs_params(w->input_dev, ABS_THROTTLE, -512, 512, 0, 0);
264 input_set_abs_params(w->input_dev, ABS_RUDDER, -512, 512, 0, 0);
265 input_set_abs_params(w->input_dev, ABS_MISC, -512, 512, 0, 0);
266
267 if (input_register_device(w->input_dev)) {
268 pr_err("failed to register input device\n");
269 goto err_free_input_dev;
270 }
271
272 return;
273
274err_free_input_dev:
275 input_free_device(w->input_dev);
276err_unregister_device:
277 parport_unregister_device(w->pardevice);
278}
279
280static void walkera0701_detach(struct parport *port)
281{
282 struct walkera_dev *w = &w_dev;
283
284 if (!w->pardevice || w->parport->number != port->number)
285 return;
286
287 input_unregister_device(w->input_dev);
288 parport_unregister_device(w->pardevice);
289 w->parport = NULL;
290}
291
292static struct parport_driver walkera0701_parport_driver = {
293 .name = "walkera0701",
294 .match_port = walkera0701_attach,
295 .detach = walkera0701_detach,
296 .devmodel = true,
297};
298
299module_parport_driver(walkera0701_parport_driver);