root/drivers/input/joystick/magellan.c

DEFINITIONS

1. magellan_crunch_nibbles
2. magellan_process_packet
3. magellan_interrupt
4. magellan_disconnect
5. magellan_connect

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (c) 1999-2001 Vojtech Pavlik
   4  */
   5 
   6 /*
   7  * Magellan and Space Mouse 6dof controller driver for Linux
   8  */
   9 
  10 /*
  11  */
  12 
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/input.h>
  17 #include <linux/serio.h>
  18 
  19 #define DRIVER_DESC     "Magellan and SpaceMouse 6dof controller driver"
  20 
  21 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  22 MODULE_DESCRIPTION(DRIVER_DESC);
  23 MODULE_LICENSE("GPL");
  24 
  25 /*
  26  * Definitions & global arrays.
  27  */
  28 
  29 #define MAGELLAN_MAX_LENGTH     32
  30 
  31 static int magellan_buttons[] = { BTN_0, BTN_1, BTN_2, BTN_3, BTN_4, BTN_5, BTN_6, BTN_7, BTN_8 };
  32 static int magellan_axes[] = { ABS_X, ABS_Y, ABS_Z, ABS_RX, ABS_RY, ABS_RZ };
  33 
  34 /*
  35  * Per-Magellan data.
  36  */
  37 
  38 struct magellan {
  39         struct input_dev *dev;
  40         int idx;
  41         unsigned char data[MAGELLAN_MAX_LENGTH];
  42         char phys[32];
  43 };
  44 
  45 /*
  46  * magellan_crunch_nibbles() verifies that the bytes sent from the Magellan
  47  * have correct upper nibbles for the lower ones, if not, the packet will
  48  * be thrown away. It also strips these upper halves to simplify further
  49  * processing.
  50  */
  51 
  52 static int magellan_crunch_nibbles(unsigned char *data, int count)
  53 {
  54         static unsigned char nibbles[16] = "0AB3D56GH9:K<MN?";
  55 
  56         do {
  57                 if (data[count] == nibbles[data[count] & 0xf])
  58                         data[count] = data[count] & 0xf;
  59                 else
  60                         return -1;
  61         } while (--count);
  62 
  63         return 0;
  64 }
  65 
  66 static void magellan_process_packet(struct magellan* magellan)
  67 {
  68         struct input_dev *dev = magellan->dev;
  69         unsigned char *data = magellan->data;
  70         int i, t;
  71 
  72         if (!magellan->idx) return;
  73 
  74         switch (magellan->data[0]) {
  75 
  76                 case 'd':                               /* Axis data */
  77                         if (magellan->idx != 25) return;
  78                         if (magellan_crunch_nibbles(data, 24)) return;
  79                         for (i = 0; i < 6; i++)
  80                                 input_report_abs(dev, magellan_axes[i],
  81                                         (data[(i << 2) + 1] << 12 | data[(i << 2) + 2] << 8 |
  82                                          data[(i << 2) + 3] <<  4 | data[(i << 2) + 4]) - 32768);
  83                         break;
  84 
  85                 case 'k':                               /* Button data */
  86                         if (magellan->idx != 4) return;
  87                         if (magellan_crunch_nibbles(data, 3)) return;
  88                         t = (data[1] << 1) | (data[2] << 5) | data[3];
  89                         for (i = 0; i < 9; i++) input_report_key(dev, magellan_buttons[i], (t >> i) & 1);
  90                         break;
  91         }
  92 
  93         input_sync(dev);
  94 }
  95 
  96 static irqreturn_t magellan_interrupt(struct serio *serio,
  97                 unsigned char data, unsigned int flags)
  98 {
  99         struct magellan* magellan = serio_get_drvdata(serio);
 100 
 101         if (data == '\r') {
 102                 magellan_process_packet(magellan);
 103                 magellan->idx = 0;
 104         } else {
 105                 if (magellan->idx < MAGELLAN_MAX_LENGTH)
 106                         magellan->data[magellan->idx++] = data;
 107         }
 108         return IRQ_HANDLED;
 109 }
 110 
 111 /*
 112  * magellan_disconnect() is the opposite of magellan_connect()
 113  */
 114 
 115 static void magellan_disconnect(struct serio *serio)
 116 {
 117         struct magellan* magellan = serio_get_drvdata(serio);
 118 
 119         serio_close(serio);
 120         serio_set_drvdata(serio, NULL);
 121         input_unregister_device(magellan->dev);
 122         kfree(magellan);
 123 }
 124 
 125 /*
 126  * magellan_connect() is the routine that is called when someone adds a
 127  * new serio device that supports Magellan protocol and registers it as
 128  * an input device.
 129  */
 130 
 131 static int magellan_connect(struct serio *serio, struct serio_driver *drv)
 132 {
 133         struct magellan *magellan;
 134         struct input_dev *input_dev;
 135         int err = -ENOMEM;
 136         int i;
 137 
 138         magellan = kzalloc(sizeof(struct magellan), GFP_KERNEL);
 139         input_dev = input_allocate_device();
 140         if (!magellan || !input_dev)
 141                 goto fail1;
 142 
 143         magellan->dev = input_dev;
 144         snprintf(magellan->phys, sizeof(magellan->phys), "%s/input0", serio->phys);
 145 
 146         input_dev->name = "LogiCad3D Magellan / SpaceMouse";
 147         input_dev->phys = magellan->phys;
 148         input_dev->id.bustype = BUS_RS232;
 149         input_dev->id.vendor = SERIO_MAGELLAN;
 150         input_dev->id.product = 0x0001;
 151         input_dev->id.version = 0x0100;
 152         input_dev->dev.parent = &serio->dev;
 153 
 154         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 155 
 156         for (i = 0; i < 9; i++)
 157                 set_bit(magellan_buttons[i], input_dev->keybit);
 158 
 159         for (i = 0; i < 6; i++)
 160                 input_set_abs_params(input_dev, magellan_axes[i], -360, 360, 0, 0);
 161 
 162         serio_set_drvdata(serio, magellan);
 163 
 164         err = serio_open(serio, drv);
 165         if (err)
 166                 goto fail2;
 167 
 168         err = input_register_device(magellan->dev);
 169         if (err)
 170                 goto fail3;
 171 
 172         return 0;
 173 
 174  fail3: serio_close(serio);
 175  fail2: serio_set_drvdata(serio, NULL);
 176  fail1: input_free_device(input_dev);
 177         kfree(magellan);
 178         return err;
 179 }
 180 
 181 /*
 182  * The serio driver structure.
 183  */
 184 
 185 static const struct serio_device_id magellan_serio_ids[] = {
 186         {
 187                 .type   = SERIO_RS232,
 188                 .proto  = SERIO_MAGELLAN,
 189                 .id     = SERIO_ANY,
 190                 .extra  = SERIO_ANY,
 191         },
 192         { 0 }
 193 };
 194 
 195 MODULE_DEVICE_TABLE(serio, magellan_serio_ids);
 196 
 197 static struct serio_driver magellan_drv = {
 198         .driver         = {
 199                 .name   = "magellan",
 200         },
 201         .description    = DRIVER_DESC,
 202         .id_table       = magellan_serio_ids,
 203         .interrupt      = magellan_interrupt,
 204         .connect        = magellan_connect,
 205         .disconnect     = magellan_disconnect,
 206 };
 207 
 208 module_serio_driver(magellan_drv);