drivers/input/touchscreen/hampshire.c

   1 /*
   2  * Hampshire serial touchscreen driver
   3  *
   4  * Copyright (c) 2010 Adam Bennett
   5  * Based on the dynapro driver (c) Tias Guns
   6  *
   7  */
   8
   9 /*
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License version 2 as published by
  12  * the Free Software Foundation.
  13  */
  14
  15 /*
  16  * 2010/04/08 Adam Bennett <abennett72@gmail.com>
  17  *   Copied dynapro.c and edited for Hampshire 4-byte protocol
  18  */
  19
  20 #include <linux/errno.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/slab.h>
  24 #include <linux/input.h>
  25 #include <linux/serio.h>
  26 #include <linux/init.h>
  27
  28 #define DRIVER_DESC     "Hampshire serial touchscreen driver"
  29
  30 MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
  31 MODULE_DESCRIPTION(DRIVER_DESC);
  32 MODULE_LICENSE("GPL");
  33
  34 /*
  35  * Definitions & global arrays.
  36  */
  37
  38 #define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
  39 #define HAMPSHIRE_FORMAT_LENGTH 4
  40 #define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
  41
  42 #define HAMPSHIRE_MIN_XC 0
  43 #define HAMPSHIRE_MAX_XC 0x1000
  44 #define HAMPSHIRE_MIN_YC 0
  45 #define HAMPSHIRE_MAX_YC 0x1000
  46
  47 #define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
  48 #define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
  49 #define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
  50
  51 /*
  52  * Per-touchscreen data.
  53  */
  54
  55 struct hampshire {
  56         struct input_dev *dev;
  57         struct serio *serio;
  58         int idx;
  59         unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
  60         char phys[32];
  61 };
  62
  63 static void hampshire_process_data(struct hampshire *phampshire)
  64 {
  65         struct input_dev *dev = phampshire->dev;
  66
  67         if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
  68                 input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
  69                 input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
  70                 input_report_key(dev, BTN_TOUCH,
  71                                  HAMPSHIRE_GET_TOUCHED(phampshire->data));
  72                 input_sync(dev);
  73
  74                 phampshire->idx = 0;
  75         }
  76 }
  77
  78 static irqreturn_t hampshire_interrupt(struct serio *serio,
  79                 unsigned char data, unsigned int flags)
  80 {
  81         struct hampshire *phampshire = serio_get_drvdata(serio);
  82
  83         phampshire->data[phampshire->idx] = data;
  84
  85         if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
  86                 hampshire_process_data(phampshire);
  87         else
  88                 dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
  89                         phampshire->data[0]);
  90
  91         return IRQ_HANDLED;
  92 }
  93
  94 static void hampshire_disconnect(struct serio *serio)
  95 {
  96         struct hampshire *phampshire = serio_get_drvdata(serio);
  97
  98         input_get_device(phampshire->dev);
  99         input_unregister_device(phampshire->dev);
 100         serio_close(serio);
 101         serio_set_drvdata(serio, NULL);
 102         input_put_device(phampshire->dev);
 103         kfree(phampshire);
 104 }
 105
 106 /*
 107  * hampshire_connect() is the routine that is called when someone adds a
 108  * new serio device that supports hampshire protocol and registers it as
 109  * an input device. This is usually accomplished using inputattach.
 110  */
 111
 112 static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
 113 {
 114         struct hampshire *phampshire;
 115         struct input_dev *input_dev;
 116         int err;
 117
 118         phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL);
 119         input_dev = input_allocate_device();
 120         if (!phampshire || !input_dev) {
 121                 err = -ENOMEM;
 122                 goto fail1;
 123         }
 124
 125         phampshire->serio = serio;
 126         phampshire->dev = input_dev;
 127         snprintf(phampshire->phys, sizeof(phampshire->phys),
 128                  "%s/input0", serio->phys);
 129
 130         input_dev->name = "Hampshire Serial TouchScreen";
 131         input_dev->phys = phampshire->phys;
 132         input_dev->id.bustype = BUS_RS232;
 133         input_dev->id.vendor = SERIO_HAMPSHIRE;
 134         input_dev->id.product = 0;
 135         input_dev->id.version = 0x0001;
 136         input_dev->dev.parent = &serio->dev;
 137         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 138         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 139         input_set_abs_params(phampshire->dev, ABS_X,
 140                              HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
 141         input_set_abs_params(phampshire->dev, ABS_Y,
 142                              HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
 143
 144         serio_set_drvdata(serio, phampshire);
 145
 146         err = serio_open(serio, drv);
 147         if (err)
 148                 goto fail2;
 149
 150         err = input_register_device(phampshire->dev);
 151         if (err)
 152                 goto fail3;
 153
 154         return 0;
 155
 156  fail3: serio_close(serio);
 157  fail2: serio_set_drvdata(serio, NULL);
 158  fail1: input_free_device(input_dev);
 159         kfree(phampshire);
 160         return err;
 161 }
 162
 163 /*
 164  * The serio driver structure.
 165  */
 166
 167 static struct serio_device_id hampshire_serio_ids[] = {
 168         {
 169                 .type   = SERIO_RS232,
 170                 .proto  = SERIO_HAMPSHIRE,
 171                 .id     = SERIO_ANY,
 172                 .extra  = SERIO_ANY,
 173         },
 174         { 0 }
 175 };
 176
 177 MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
 178
 179 static struct serio_driver hampshire_drv = {
 180         .driver         = {
 181                 .name   = "hampshire",
 182         },
 183         .description    = DRIVER_DESC,
 184         .id_table       = hampshire_serio_ids,
 185         .interrupt      = hampshire_interrupt,
 186         .connect        = hampshire_connect,
 187         .disconnect     = hampshire_disconnect,
 188 };
 189
 190 /*
 191  * The functions for inserting/removing us as a module.
 192  */
 193
 194 static int __init hampshire_init(void)
 195 {
 196         return serio_register_driver(&hampshire_drv);
 197 }
 198
 199 static void __exit hampshire_exit(void)
 200 {
 201         serio_unregister_driver(&hampshire_drv);
 202 }
 203
 204 module_init(hampshire_init);
 205 module_exit(hampshire_exit);