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 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 */ 124 125 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 */ 152 153 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 */ 168 169 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