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 /*
36 */
37
38 #include <linux/kernel.h>
39 #include <linux/module.h>
40 #include <linux/slab.h>
41 #include <linux/input.h>
42 #include <linux/serio.h>
43
44 #define DRIVER_DESC "Handykey Twiddler keyboard as a joystick driver"
45
46 MODULE_DESCRIPTION(DRIVER_DESC);
47 MODULE_LICENSE("GPL");
48
49 /*
50 * Constants.
51 */
52
53 #define TWIDJOY_MAX_LENGTH 5
54
55 static struct twidjoy_button_spec {
56 int bitshift;
57 int bitmask;
58 int buttons[3];
59 }
60 twidjoy_buttons[] = {
61 { 0, 3, { BTN_A, BTN_B, BTN_C } },
62 { 2, 3, { BTN_X, BTN_Y, BTN_Z } },
63 { 4, 3, { BTN_TL, BTN_TR, BTN_TR2 } },
64 { 6, 3, { BTN_SELECT, BTN_START, BTN_MODE } },
65 { 8, 1, { BTN_BASE5 } },
66 { 9, 1, { BTN_BASE } },
67 { 10, 1, { BTN_BASE3 } },
68 { 11, 1, { BTN_BASE4 } },
69 { 12, 1, { BTN_BASE2 } },
70 { 13, 1, { BTN_BASE6 } },
71 { 0, 0, { 0 } }
72 };
73
74 /*
75 * Per-Twiddler data.
76 */
77
78 struct twidjoy {
79 struct input_dev *dev;
80 int idx;
81 unsigned char data[TWIDJOY_MAX_LENGTH];
82 char phys[32];
83 };
84
85 /*
86 * twidjoy_process_packet() decodes packets the driver receives from the
87 * Twiddler. It updates the data accordingly.
88 */
89
twidjoy_process_packet(struct twidjoy * twidjoy)90 static void twidjoy_process_packet(struct twidjoy *twidjoy)
91 {
92 struct input_dev *dev = twidjoy->dev;
93 unsigned char *data = twidjoy->data;
94 struct twidjoy_button_spec *bp;
95 int button_bits, abs_x, abs_y;
96
97 button_bits = ((data[1] & 0x7f) << 7) | (data[0] & 0x7f);
98
99 for (bp = twidjoy_buttons; bp->bitmask; bp++) {
100 int value = (button_bits & (bp->bitmask << bp->bitshift)) >> bp->bitshift;
101 int i;
102
103 for (i = 0; i < bp->bitmask; i++)
104 input_report_key(dev, bp->buttons[i], i+1 == value);
105 }
106
107 abs_x = ((data[4] & 0x07) << 5) | ((data[3] & 0x7C) >> 2);
108 if (data[4] & 0x08) abs_x -= 256;
109
110 abs_y = ((data[3] & 0x01) << 7) | ((data[2] & 0x7F) >> 0);
111 if (data[3] & 0x02) abs_y -= 256;
112
113 input_report_abs(dev, ABS_X, -abs_x);
114 input_report_abs(dev, ABS_Y, +abs_y);
115
116 input_sync(dev);
117 }
118
119 /*
120 * twidjoy_interrupt() is called by the low level driver when characters
121 * are ready for us. We then buffer them for further processing, or call the
122 * packet processing routine.
123 */
124
twidjoy_interrupt(struct serio * serio,unsigned char data,unsigned int flags)125 static irqreturn_t twidjoy_interrupt(struct serio *serio, unsigned char data, unsigned int flags)
126 {
127 struct twidjoy *twidjoy = serio_get_drvdata(serio);
128
129 /* All Twiddler packets are 5 bytes. The fact that the first byte
130 * has a MSB of 0 and all other bytes have a MSB of 1 can be used
131 * to check and regain sync. */
132
133 if ((data & 0x80) == 0)
134 twidjoy->idx = 0; /* this byte starts a new packet */
135 else if (twidjoy->idx == 0)
136 return IRQ_HANDLED; /* wrong MSB -- ignore this byte */
137
138 if (twidjoy->idx < TWIDJOY_MAX_LENGTH)
139 twidjoy->data[twidjoy->idx++] = data;
140
141 if (twidjoy->idx == TWIDJOY_MAX_LENGTH) {
142 twidjoy_process_packet(twidjoy);
143 twidjoy->idx = 0;
144 }
145
146 return IRQ_HANDLED;
147 }
148
149 /*
150 * twidjoy_disconnect() is the opposite of twidjoy_connect()
151 */
152
twidjoy_disconnect(struct serio * serio)153 static void twidjoy_disconnect(struct serio *serio)
154 {
155 struct twidjoy *twidjoy = serio_get_drvdata(serio);
156
157 serio_close(serio);
158 serio_set_drvdata(serio, NULL);
159 input_unregister_device(twidjoy->dev);
160 kfree(twidjoy);
161 }
162
163 /*
164 * twidjoy_connect() is the routine that is called when someone adds a
165 * new serio device. It looks for the Twiddler, and if found, registers
166 * it as an input device.
167 */
168
twidjoy_connect(struct serio * serio,struct serio_driver * drv)169 static int twidjoy_connect(struct serio *serio, struct serio_driver *drv)
170 {
171 struct twidjoy_button_spec *bp;
172 struct twidjoy *twidjoy;
173 struct input_dev *input_dev;
174 int err = -ENOMEM;
175 int i;
176
177 twidjoy = kzalloc(sizeof(struct twidjoy), GFP_KERNEL);
178 input_dev = input_allocate_device();
179 if (!twidjoy || !input_dev)
180 goto fail1;
181
182 twidjoy->dev = input_dev;
183 snprintf(twidjoy->phys, sizeof(twidjoy->phys), "%s/input0", serio->phys);
184
185 input_dev->name = "Handykey Twiddler";
186 input_dev->phys = twidjoy->phys;
187 input_dev->id.bustype = BUS_RS232;
188 input_dev->id.vendor = SERIO_TWIDJOY;
189 input_dev->id.product = 0x0001;
190 input_dev->id.version = 0x0100;
191 input_dev->dev.parent = &serio->dev;
192
193 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
194 input_set_abs_params(input_dev, ABS_X, -50, 50, 4, 4);
195 input_set_abs_params(input_dev, ABS_Y, -50, 50, 4, 4);
196
197 for (bp = twidjoy_buttons; bp->bitmask; bp++)
198 for (i = 0; i < bp->bitmask; i++)
199 set_bit(bp->buttons[i], input_dev->keybit);
200
201 serio_set_drvdata(serio, twidjoy);
202
203 err = serio_open(serio, drv);
204 if (err)
205 goto fail2;
206
207 err = input_register_device(twidjoy->dev);
208 if (err)
209 goto fail3;
210
211 return 0;
212
213 fail3: serio_close(serio);
214 fail2: serio_set_drvdata(serio, NULL);
215 fail1: input_free_device(input_dev);
216 kfree(twidjoy);
217 return err;
218 }
219
220 /*
221 * The serio driver structure.
222 */
223
224 static const struct serio_device_id twidjoy_serio_ids[] = {
225 {
226 .type = SERIO_RS232,
227 .proto = SERIO_TWIDJOY,
228 .id = SERIO_ANY,
229 .extra = SERIO_ANY,
230 },
231 { 0 }
232 };
233
234 MODULE_DEVICE_TABLE(serio, twidjoy_serio_ids);
235
236 static struct serio_driver twidjoy_drv = {
237 .driver = {
238 .name = "twidjoy",
239 },
240 .description = DRIVER_DESC,
241 .id_table = twidjoy_serio_ids,
242 .interrupt = twidjoy_interrupt,
243 .connect = twidjoy_connect,
244 .disconnect = twidjoy_disconnect,
245 };
246
247 module_serio_driver(twidjoy_drv);
248