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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 | |
56 | MODULE_DESCRIPTION(DRIVER_DESC); |
57 | MODULE_LICENSE("GPL"); |
58 | |
59 | /* |
60 | * Constants. |
61 | */ |
62 | |
63 | #define ZHENHUA_MAX_LENGTH 5 |
64 | |
65 | /* |
66 | * Zhen Hua data. |
67 | */ |
68 | |
69 | struct 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" */ |
78 | static 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 | |
91 | static 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 | |
110 | static 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 | |
138 | static 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 | |
154 | static 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 | |
205 | static 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 | |
215 | MODULE_DEVICE_TABLE(serio, zhenhua_serio_ids); |
216 | |
217 | static 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 | module_serio_driver(zhenhua_drv); |
229 |
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