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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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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 | |
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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 | ||
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31 | #include <linux/kernel.h> |
32 | #include <linux/module.h> | |
33 | #include <linux/slab.h> | |
012bd2a5 | 34 | #include <linux/bitrev.h> |
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35 | #include <linux/input.h> |
36 | #include <linux/serio.h> | |
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37 | |
38 | #define DRIVER_DESC "RC transmitter with 5-byte Zhen Hua protocol joystick driver" | |
39 | ||
40 | MODULE_DESCRIPTION(DRIVER_DESC); | |
41 | MODULE_LICENSE("GPL"); | |
42 | ||
43 | /* | |
44 | * Constants. | |
45 | */ | |
46 | ||
47 | #define ZHENHUA_MAX_LENGTH 5 | |
48 | ||
49 | /* | |
50 | * Zhen Hua data. | |
51 | */ | |
52 | ||
53 | struct zhenhua { | |
54 | struct input_dev *dev; | |
55 | int idx; | |
56 | unsigned char data[ZHENHUA_MAX_LENGTH]; | |
57 | char phys[32]; | |
58 | }; | |
59 | ||
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60 | /* |
61 | * zhenhua_process_packet() decodes packets the driver receives from the | |
62 | * RC transmitter. It updates the data accordingly. | |
63 | */ | |
64 | ||
65 | static 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 | ||
84 | static 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) | |
012bd2a5 | 98 | zhenhua->data[zhenhua->idx++] = bitrev8(data); |
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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 | ||
112 | static 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 | ||
128 | static 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 | ||
b06bc6b6 | 179 | static const struct serio_device_id zhenhua_serio_ids[] = { |
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180 | { |
181 | .type = SERIO_RS232, | |
182 | .proto = SERIO_ZHENHUA, | |
183 | .id = SERIO_ANY, | |
184 | .extra = SERIO_ANY, | |
185 | }, | |
186 | { 0 } | |
187 | }; | |
188 | ||
189 | MODULE_DEVICE_TABLE(serio, zhenhua_serio_ids); | |
190 | ||
191 | static 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 | ||
65ac9f7a | 202 | module_serio_driver(zhenhua_drv); |