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3e24e2b5 MK |
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 | ||
65ac9f7a | 228 | module_serio_driver(zhenhua_drv); |