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
twidjoy_process_packet(struct twidjoy * twidjoy)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, bp->buttons[i], 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, -abs_x);
111 input_report_abs(dev, ABS_Y, +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
twidjoy_interrupt(struct serio * serio,unsigned char data,unsigned int flags)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
twidjoy_disconnect(struct serio * serio)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(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
twidjoy_connect(struct serio * serio,struct serio_driver * drv)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(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(twidjoy->phys, sizeof(twidjoy->phys), "%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(input_dev, ABS_X, -50, 50, 4, 4);
192 input_set_abs_params(input_dev, ABS_Y, -50, 50, 4, 4);
193
194 for (bp = twidjoy_buttons; bp->bitmask; bp++)
195 for (i = 0; i < bp->bitmask; i++)
196 set_bit(bp->buttons[i], input_dev->keybit);
197
198 serio_set_drvdata(serio, 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(input_dev);
213 kfree(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