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