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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * derived from "twidjoy.c"
4 *
5 * Copyright (c) 2008 Martin Kebert
6 * Copyright (c) 2001 Arndt Schoenewald
7 * Copyright (c) 2000-2001 Vojtech Pavlik
8 * Copyright (c) 2000 Mark Fletcher
9 */
10
11/*
12 * Driver to use 4CH RC transmitter using Zhen Hua 5-byte protocol (Walkera Lama,
13 * EasyCopter etc.) as a joystick under Linux.
14 *
15 * RC transmitters using Zhen Hua 5-byte protocol are cheap four channels
16 * transmitters for control a RC planes or RC helicopters with possibility to
17 * connect on a serial port.
18 * Data coming from transmitter is in this order:
19 * 1. byte = synchronisation byte
20 * 2. byte = X axis
21 * 3. byte = Y axis
22 * 4. byte = RZ axis
23 * 5. byte = Z axis
24 * (and this is repeated)
25 *
26 * For questions or feedback regarding this driver module please contact:
27 * Martin Kebert <gkmarty@gmail.com> - but I am not a C-programmer nor kernel
28 * coder :-(
29 */
30
31#include <linux/kernel.h>
32#include <linux/module.h>
33#include <linux/slab.h>
34#include <linux/bitrev.h>
35#include <linux/input.h>
36#include <linux/serio.h>
37
38#define DRIVER_DESC "RC transmitter with 5-byte Zhen Hua protocol joystick driver"
39
40MODULE_DESCRIPTION(DRIVER_DESC);
41MODULE_LICENSE("GPL");
42
43/*
44 * Constants.
45 */
46
47#define ZHENHUA_MAX_LENGTH 5
48
49/*
50 * Zhen Hua data.
51 */
52
53struct zhenhua {
54 struct input_dev *dev;
55 int idx;
56 unsigned char data[ZHENHUA_MAX_LENGTH];
57 char phys[32];
58};
59
60/*
61 * zhenhua_process_packet() decodes packets the driver receives from the
62 * RC transmitter. It updates the data accordingly.
63 */
64
65static void zhenhua_process_packet(struct zhenhua *zhenhua)
66{
67 struct input_dev *dev = zhenhua->dev;
68 unsigned char *data = zhenhua->data;
69
70 input_report_abs(dev, ABS_Y, data[1]);
71 input_report_abs(dev, ABS_X, data[2]);
72 input_report_abs(dev, ABS_RZ, data[3]);
73 input_report_abs(dev, ABS_Z, data[4]);
74
75 input_sync(dev);
76}
77
78/*
79 * zhenhua_interrupt() is called by the low level driver when characters
80 * are ready for us. We then buffer them for further processing, or call the
81 * packet processing routine.
82 */
83
84static irqreturn_t zhenhua_interrupt(struct serio *serio, unsigned char data, unsigned int flags)
85{
86 struct zhenhua *zhenhua = serio_get_drvdata(serio);
87
88 /* All Zhen Hua packets are 5 bytes. The fact that the first byte
89 * is allways 0xf7 and all others are in range 0x32 - 0xc8 (50-200)
90 * can be used to check and regain sync. */
91
92 if (data == 0xef)
93 zhenhua->idx = 0; /* this byte starts a new packet */
94 else if (zhenhua->idx == 0)
95 return IRQ_HANDLED; /* wrong MSB -- ignore this byte */
96
97 if (zhenhua->idx < ZHENHUA_MAX_LENGTH)
98 zhenhua->data[zhenhua->idx++] = bitrev8(data);
99
100 if (zhenhua->idx == ZHENHUA_MAX_LENGTH) {
101 zhenhua_process_packet(zhenhua);
102 zhenhua->idx = 0;
103 }
104
105 return IRQ_HANDLED;
106}
107
108/*
109 * zhenhua_disconnect() is the opposite of zhenhua_connect()
110 */
111
112static void zhenhua_disconnect(struct serio *serio)
113{
114 struct zhenhua *zhenhua = serio_get_drvdata(serio);
115
116 serio_close(serio);
117 serio_set_drvdata(serio, NULL);
118 input_unregister_device(zhenhua->dev);
119 kfree(zhenhua);
120}
121
122/*
123 * zhenhua_connect() is the routine that is called when someone adds a
124 * new serio device. It looks for the Twiddler, and if found, registers
125 * it as an input device.
126 */
127
128static int zhenhua_connect(struct serio *serio, struct serio_driver *drv)
129{
130 struct zhenhua *zhenhua;
131 struct input_dev *input_dev;
132 int err = -ENOMEM;
133
134 zhenhua = kzalloc(sizeof(struct zhenhua), GFP_KERNEL);
135 input_dev = input_allocate_device();
136 if (!zhenhua || !input_dev)
137 goto fail1;
138
139 zhenhua->dev = input_dev;
140 snprintf(zhenhua->phys, sizeof(zhenhua->phys), "%s/input0", serio->phys);
141
142 input_dev->name = "Zhen Hua 5-byte device";
143 input_dev->phys = zhenhua->phys;
144 input_dev->id.bustype = BUS_RS232;
145 input_dev->id.vendor = SERIO_ZHENHUA;
146 input_dev->id.product = 0x0001;
147 input_dev->id.version = 0x0100;
148 input_dev->dev.parent = &serio->dev;
149
150 input_dev->evbit[0] = BIT(EV_ABS);
151 input_set_abs_params(input_dev, ABS_X, 50, 200, 0, 0);
152 input_set_abs_params(input_dev, ABS_Y, 50, 200, 0, 0);
153 input_set_abs_params(input_dev, ABS_Z, 50, 200, 0, 0);
154 input_set_abs_params(input_dev, ABS_RZ, 50, 200, 0, 0);
155
156 serio_set_drvdata(serio, zhenhua);
157
158 err = serio_open(serio, drv);
159 if (err)
160 goto fail2;
161
162 err = input_register_device(zhenhua->dev);
163 if (err)
164 goto fail3;
165
166 return 0;
167
168 fail3: serio_close(serio);
169 fail2: serio_set_drvdata(serio, NULL);
170 fail1: input_free_device(input_dev);
171 kfree(zhenhua);
172 return err;
173}
174
175/*
176 * The serio driver structure.
177 */
178
179static const struct serio_device_id zhenhua_serio_ids[] = {
180 {
181 .type = SERIO_RS232,
182 .proto = SERIO_ZHENHUA,
183 .id = SERIO_ANY,
184 .extra = SERIO_ANY,
185 },
186 { 0 }
187};
188
189MODULE_DEVICE_TABLE(serio, zhenhua_serio_ids);
190
191static struct serio_driver zhenhua_drv = {
192 .driver = {
193 .name = "zhenhua",
194 },
195 .description = DRIVER_DESC,
196 .id_table = zhenhua_serio_ids,
197 .interrupt = zhenhua_interrupt,
198 .connect = zhenhua_connect,
199 .disconnect = zhenhua_disconnect,
200};
201
202module_serio_driver(zhenhua_drv);
1/*
2 * derived from "twidjoy.c"
3 *
4 * Copyright (c) 2008 Martin Kebert
5 * Copyright (c) 2001 Arndt Schoenewald
6 * Copyright (c) 2000-2001 Vojtech Pavlik
7 * Copyright (c) 2000 Mark Fletcher
8 *
9 */
10
11/*
12 * Driver to use 4CH RC transmitter using Zhen Hua 5-byte protocol (Walkera Lama,
13 * EasyCopter etc.) as a joystick under Linux.
14 *
15 * RC transmitters using Zhen Hua 5-byte protocol are cheap four channels
16 * transmitters for control a RC planes or RC helicopters with possibility to
17 * connect on a serial port.
18 * Data coming from transmitter is in this order:
19 * 1. byte = synchronisation byte
20 * 2. byte = X axis
21 * 3. byte = Y axis
22 * 4. byte = RZ axis
23 * 5. byte = Z axis
24 * (and this is repeated)
25 *
26 * For questions or feedback regarding this driver module please contact:
27 * Martin Kebert <gkmarty@gmail.com> - but I am not a C-programmer nor kernel
28 * coder :-(
29 */
30
31/*
32 * This program is free software; you can redistribute it and/or modify
33 * it under the terms of the GNU General Public License as published by
34 * the Free Software Foundation; either version 2 of the License, or
35 * (at your option) any later version.
36 *
37 * This program is distributed in the hope that it will be useful,
38 * but WITHOUT ANY WARRANTY; without even the implied warranty of
39 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
40 * GNU General Public License for more details.
41 *
42 * You should have received a copy of the GNU General Public License
43 * along with this program; if not, write to the Free Software
44 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
45 */
46
47#include <linux/kernel.h>
48#include <linux/module.h>
49#include <linux/slab.h>
50#include <linux/input.h>
51#include <linux/serio.h>
52#include <linux/init.h>
53
54#define DRIVER_DESC "RC transmitter with 5-byte Zhen Hua protocol joystick driver"
55
56MODULE_DESCRIPTION(DRIVER_DESC);
57MODULE_LICENSE("GPL");
58
59/*
60 * Constants.
61 */
62
63#define ZHENHUA_MAX_LENGTH 5
64
65/*
66 * Zhen Hua data.
67 */
68
69struct zhenhua {
70 struct input_dev *dev;
71 int idx;
72 unsigned char data[ZHENHUA_MAX_LENGTH];
73 char phys[32];
74};
75
76
77/* bits in all incoming bytes needs to be "reversed" */
78static int zhenhua_bitreverse(int x)
79{
80 x = ((x & 0xaa) >> 1) | ((x & 0x55) << 1);
81 x = ((x & 0xcc) >> 2) | ((x & 0x33) << 2);
82 x = ((x & 0xf0) >> 4) | ((x & 0x0f) << 4);
83 return x;
84}
85
86/*
87 * zhenhua_process_packet() decodes packets the driver receives from the
88 * RC transmitter. It updates the data accordingly.
89 */
90
91static void zhenhua_process_packet(struct zhenhua *zhenhua)
92{
93 struct input_dev *dev = zhenhua->dev;
94 unsigned char *data = zhenhua->data;
95
96 input_report_abs(dev, ABS_Y, data[1]);
97 input_report_abs(dev, ABS_X, data[2]);
98 input_report_abs(dev, ABS_RZ, data[3]);
99 input_report_abs(dev, ABS_Z, data[4]);
100
101 input_sync(dev);
102}
103
104/*
105 * zhenhua_interrupt() is called by the low level driver when characters
106 * are ready for us. We then buffer them for further processing, or call the
107 * packet processing routine.
108 */
109
110static irqreturn_t zhenhua_interrupt(struct serio *serio, unsigned char data, unsigned int flags)
111{
112 struct zhenhua *zhenhua = serio_get_drvdata(serio);
113
114 /* All Zhen Hua packets are 5 bytes. The fact that the first byte
115 * is allways 0xf7 and all others are in range 0x32 - 0xc8 (50-200)
116 * can be used to check and regain sync. */
117
118 if (data == 0xef)
119 zhenhua->idx = 0; /* this byte starts a new packet */
120 else if (zhenhua->idx == 0)
121 return IRQ_HANDLED; /* wrong MSB -- ignore this byte */
122
123 if (zhenhua->idx < ZHENHUA_MAX_LENGTH)
124 zhenhua->data[zhenhua->idx++] = zhenhua_bitreverse(data);
125
126 if (zhenhua->idx == ZHENHUA_MAX_LENGTH) {
127 zhenhua_process_packet(zhenhua);
128 zhenhua->idx = 0;
129 }
130
131 return IRQ_HANDLED;
132}
133
134/*
135 * zhenhua_disconnect() is the opposite of zhenhua_connect()
136 */
137
138static void zhenhua_disconnect(struct serio *serio)
139{
140 struct zhenhua *zhenhua = serio_get_drvdata(serio);
141
142 serio_close(serio);
143 serio_set_drvdata(serio, NULL);
144 input_unregister_device(zhenhua->dev);
145 kfree(zhenhua);
146}
147
148/*
149 * zhenhua_connect() is the routine that is called when someone adds a
150 * new serio device. It looks for the Twiddler, and if found, registers
151 * it as an input device.
152 */
153
154static int zhenhua_connect(struct serio *serio, struct serio_driver *drv)
155{
156 struct zhenhua *zhenhua;
157 struct input_dev *input_dev;
158 int err = -ENOMEM;
159
160 zhenhua = kzalloc(sizeof(struct zhenhua), GFP_KERNEL);
161 input_dev = input_allocate_device();
162 if (!zhenhua || !input_dev)
163 goto fail1;
164
165 zhenhua->dev = input_dev;
166 snprintf(zhenhua->phys, sizeof(zhenhua->phys), "%s/input0", serio->phys);
167
168 input_dev->name = "Zhen Hua 5-byte device";
169 input_dev->phys = zhenhua->phys;
170 input_dev->id.bustype = BUS_RS232;
171 input_dev->id.vendor = SERIO_ZHENHUA;
172 input_dev->id.product = 0x0001;
173 input_dev->id.version = 0x0100;
174 input_dev->dev.parent = &serio->dev;
175
176 input_dev->evbit[0] = BIT(EV_ABS);
177 input_set_abs_params(input_dev, ABS_X, 50, 200, 0, 0);
178 input_set_abs_params(input_dev, ABS_Y, 50, 200, 0, 0);
179 input_set_abs_params(input_dev, ABS_Z, 50, 200, 0, 0);
180 input_set_abs_params(input_dev, ABS_RZ, 50, 200, 0, 0);
181
182 serio_set_drvdata(serio, zhenhua);
183
184 err = serio_open(serio, drv);
185 if (err)
186 goto fail2;
187
188 err = input_register_device(zhenhua->dev);
189 if (err)
190 goto fail3;
191
192 return 0;
193
194 fail3: serio_close(serio);
195 fail2: serio_set_drvdata(serio, NULL);
196 fail1: input_free_device(input_dev);
197 kfree(zhenhua);
198 return err;
199}
200
201/*
202 * The serio driver structure.
203 */
204
205static struct serio_device_id zhenhua_serio_ids[] = {
206 {
207 .type = SERIO_RS232,
208 .proto = SERIO_ZHENHUA,
209 .id = SERIO_ANY,
210 .extra = SERIO_ANY,
211 },
212 { 0 }
213};
214
215MODULE_DEVICE_TABLE(serio, zhenhua_serio_ids);
216
217static struct serio_driver zhenhua_drv = {
218 .driver = {
219 .name = "zhenhua",
220 },
221 .description = DRIVER_DESC,
222 .id_table = zhenhua_serio_ids,
223 .interrupt = zhenhua_interrupt,
224 .connect = zhenhua_connect,
225 .disconnect = zhenhua_disconnect,
226};
227
228/*
229 * The functions for inserting/removing us as a module.
230 */
231
232static int __init zhenhua_init(void)
233{
234 return serio_register_driver(&zhenhua_drv);
235}
236
237static void __exit zhenhua_exit(void)
238{
239 serio_unregister_driver(&zhenhua_drv);
240}
241
242module_init(zhenhua_init);
243module_exit(zhenhua_exit);