1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Copyright (c) 2001 Arndt Schoenewald |
4 | * Copyright (c) 2000-2001 Vojtech Pavlik |
5 | * Copyright (c) 2000 Mark Fletcher |
6 | * |
7 | * Sponsored by Quelltext AG (http://www.quelltext-ag.de), Dortmund, Germany |
8 | */ |
9 | |
10 | /* |
11 | * Driver to use Handykey's Twiddler (the first edition, i.e. the one with |
12 | * the RS232 interface) as a joystick under Linux |
13 | * |
14 | * The Twiddler is a one-handed chording keyboard featuring twelve buttons on |
15 | * the front, six buttons on the top, and a built-in tilt sensor. The buttons |
16 | * on the front, which are grouped as four rows of three buttons, are pressed |
17 | * by the four fingers (this implies only one button per row can be held down |
18 | * at the same time) and the buttons on the top are for the thumb. The tilt |
19 | * sensor delivers X and Y axis data depending on how the Twiddler is held. |
20 | * Additional information can be found at http://www.handykey.com. |
21 | * |
22 | * This driver does not use the Twiddler for its intended purpose, i.e. as |
23 | * a chording keyboard, but as a joystick: pressing and releasing a button |
24 | * immediately sends a corresponding button event, and tilting it generates |
25 | * corresponding ABS_X and ABS_Y events. This turns the Twiddler into a game |
26 | * controller with amazing 18 buttons :-) |
27 | * |
28 | * Note: The Twiddler2 (the successor of the Twiddler that connects directly |
29 | * to the PS/2 keyboard and mouse ports) is NOT supported by this driver! |
30 | * |
31 | * For questions or feedback regarding this driver module please contact: |
32 | * Arndt Schoenewald <arndt@quelltext.com> |
33 | */ |
34 | |
35 | #include <linux/kernel.h> |
36 | #include <linux/module.h> |
37 | #include <linux/slab.h> |
38 | #include <linux/input.h> |
39 | #include <linux/serio.h> |
40 | |
41 | #define DRIVER_DESC "Handykey Twiddler keyboard as a joystick driver" |
42 | |
43 | MODULE_DESCRIPTION(DRIVER_DESC); |
44 | MODULE_LICENSE("GPL" ); |
45 | |
46 | /* |
47 | * Constants. |
48 | */ |
49 | |
50 | #define TWIDJOY_MAX_LENGTH 5 |
51 | |
52 | static struct twidjoy_button_spec { |
53 | int bitshift; |
54 | int bitmask; |
55 | int buttons[3]; |
56 | } |
57 | twidjoy_buttons[] = { |
58 | { 0, 3, { BTN_A, BTN_B, BTN_C } }, |
59 | { 2, 3, { BTN_X, BTN_Y, BTN_Z } }, |
60 | { 4, 3, { BTN_TL, BTN_TR, BTN_TR2 } }, |
61 | { 6, 3, { BTN_SELECT, BTN_START, BTN_MODE } }, |
62 | { 8, 1, { BTN_BASE5 } }, |
63 | { 9, 1, { BTN_BASE } }, |
64 | { 10, 1, { BTN_BASE3 } }, |
65 | { 11, 1, { BTN_BASE4 } }, |
66 | { 12, 1, { BTN_BASE2 } }, |
67 | { 13, 1, { BTN_BASE6 } }, |
68 | { 0, 0, { 0 } } |
69 | }; |
70 | |
71 | /* |
72 | * Per-Twiddler data. |
73 | */ |
74 | |
75 | struct twidjoy { |
76 | struct input_dev *dev; |
77 | int idx; |
78 | unsigned char data[TWIDJOY_MAX_LENGTH]; |
79 | char phys[32]; |
80 | }; |
81 | |
82 | /* |
83 | * twidjoy_process_packet() decodes packets the driver receives from the |
84 | * Twiddler. It updates the data accordingly. |
85 | */ |
86 | |
87 | static void twidjoy_process_packet(struct twidjoy *twidjoy) |
88 | { |
89 | struct input_dev *dev = twidjoy->dev; |
90 | unsigned char *data = twidjoy->data; |
91 | struct twidjoy_button_spec *bp; |
92 | int button_bits, abs_x, abs_y; |
93 | |
94 | button_bits = ((data[1] & 0x7f) << 7) | (data[0] & 0x7f); |
95 | |
96 | for (bp = twidjoy_buttons; bp->bitmask; bp++) { |
97 | int value = (button_bits & (bp->bitmask << bp->bitshift)) >> bp->bitshift; |
98 | int i; |
99 | |
100 | for (i = 0; i < bp->bitmask; i++) |
101 | input_report_key(dev, code: bp->buttons[i], value: i+1 == value); |
102 | } |
103 | |
104 | abs_x = ((data[4] & 0x07) << 5) | ((data[3] & 0x7C) >> 2); |
105 | if (data[4] & 0x08) abs_x -= 256; |
106 | |
107 | abs_y = ((data[3] & 0x01) << 7) | ((data[2] & 0x7F) >> 0); |
108 | if (data[3] & 0x02) abs_y -= 256; |
109 | |
110 | input_report_abs(dev, ABS_X, value: -abs_x); |
111 | input_report_abs(dev, ABS_Y, value: +abs_y); |
112 | |
113 | input_sync(dev); |
114 | } |
115 | |
116 | /* |
117 | * twidjoy_interrupt() is called by the low level driver when characters |
118 | * are ready for us. We then buffer them for further processing, or call the |
119 | * packet processing routine. |
120 | */ |
121 | |
122 | static irqreturn_t twidjoy_interrupt(struct serio *serio, unsigned char data, unsigned int flags) |
123 | { |
124 | struct twidjoy *twidjoy = serio_get_drvdata(serio); |
125 | |
126 | /* All Twiddler packets are 5 bytes. The fact that the first byte |
127 | * has a MSB of 0 and all other bytes have a MSB of 1 can be used |
128 | * to check and regain sync. */ |
129 | |
130 | if ((data & 0x80) == 0) |
131 | twidjoy->idx = 0; /* this byte starts a new packet */ |
132 | else if (twidjoy->idx == 0) |
133 | return IRQ_HANDLED; /* wrong MSB -- ignore this byte */ |
134 | |
135 | if (twidjoy->idx < TWIDJOY_MAX_LENGTH) |
136 | twidjoy->data[twidjoy->idx++] = data; |
137 | |
138 | if (twidjoy->idx == TWIDJOY_MAX_LENGTH) { |
139 | twidjoy_process_packet(twidjoy); |
140 | twidjoy->idx = 0; |
141 | } |
142 | |
143 | return IRQ_HANDLED; |
144 | } |
145 | |
146 | /* |
147 | * twidjoy_disconnect() is the opposite of twidjoy_connect() |
148 | */ |
149 | |
150 | static void twidjoy_disconnect(struct serio *serio) |
151 | { |
152 | struct twidjoy *twidjoy = serio_get_drvdata(serio); |
153 | |
154 | serio_close(serio); |
155 | serio_set_drvdata(serio, NULL); |
156 | input_unregister_device(twidjoy->dev); |
157 | kfree(objp: twidjoy); |
158 | } |
159 | |
160 | /* |
161 | * twidjoy_connect() is the routine that is called when someone adds a |
162 | * new serio device. It looks for the Twiddler, and if found, registers |
163 | * it as an input device. |
164 | */ |
165 | |
166 | static int twidjoy_connect(struct serio *serio, struct serio_driver *drv) |
167 | { |
168 | struct twidjoy_button_spec *bp; |
169 | struct twidjoy *twidjoy; |
170 | struct input_dev *input_dev; |
171 | int err = -ENOMEM; |
172 | int i; |
173 | |
174 | twidjoy = kzalloc(size: sizeof(struct twidjoy), GFP_KERNEL); |
175 | input_dev = input_allocate_device(); |
176 | if (!twidjoy || !input_dev) |
177 | goto fail1; |
178 | |
179 | twidjoy->dev = input_dev; |
180 | snprintf(buf: twidjoy->phys, size: sizeof(twidjoy->phys), fmt: "%s/input0" , serio->phys); |
181 | |
182 | input_dev->name = "Handykey Twiddler" ; |
183 | input_dev->phys = twidjoy->phys; |
184 | input_dev->id.bustype = BUS_RS232; |
185 | input_dev->id.vendor = SERIO_TWIDJOY; |
186 | input_dev->id.product = 0x0001; |
187 | input_dev->id.version = 0x0100; |
188 | input_dev->dev.parent = &serio->dev; |
189 | |
190 | input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); |
191 | input_set_abs_params(dev: input_dev, ABS_X, min: -50, max: 50, fuzz: 4, flat: 4); |
192 | input_set_abs_params(dev: input_dev, ABS_Y, min: -50, max: 50, fuzz: 4, flat: 4); |
193 | |
194 | for (bp = twidjoy_buttons; bp->bitmask; bp++) |
195 | for (i = 0; i < bp->bitmask; i++) |
196 | set_bit(nr: bp->buttons[i], addr: input_dev->keybit); |
197 | |
198 | serio_set_drvdata(serio, data: twidjoy); |
199 | |
200 | err = serio_open(serio, drv); |
201 | if (err) |
202 | goto fail2; |
203 | |
204 | err = input_register_device(twidjoy->dev); |
205 | if (err) |
206 | goto fail3; |
207 | |
208 | return 0; |
209 | |
210 | fail3: serio_close(serio); |
211 | fail2: serio_set_drvdata(serio, NULL); |
212 | fail1: input_free_device(dev: input_dev); |
213 | kfree(objp: twidjoy); |
214 | return err; |
215 | } |
216 | |
217 | /* |
218 | * The serio driver structure. |
219 | */ |
220 | |
221 | static const struct serio_device_id twidjoy_serio_ids[] = { |
222 | { |
223 | .type = SERIO_RS232, |
224 | .proto = SERIO_TWIDJOY, |
225 | .id = SERIO_ANY, |
226 | .extra = SERIO_ANY, |
227 | }, |
228 | { 0 } |
229 | }; |
230 | |
231 | MODULE_DEVICE_TABLE(serio, twidjoy_serio_ids); |
232 | |
233 | static struct serio_driver twidjoy_drv = { |
234 | .driver = { |
235 | .name = "twidjoy" , |
236 | }, |
237 | .description = DRIVER_DESC, |
238 | .id_table = twidjoy_serio_ids, |
239 | .interrupt = twidjoy_interrupt, |
240 | .connect = twidjoy_connect, |
241 | .disconnect = twidjoy_disconnect, |
242 | }; |
243 | |
244 | module_serio_driver(twidjoy_drv); |
245 | |