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
  27 #define DRIVER_DESC     "Hampshire serial touchscreen driver"
  28
  29 MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
  30 MODULE_DESCRIPTION(DRIVER_DESC);
  31 MODULE_LICENSE("GPL");
  32
  33 /*
  34  * Definitions & global arrays.
  35  */
  36
  37 #define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
  38 #define HAMPSHIRE_FORMAT_LENGTH 4
  39 #define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
  40
  41 #define HAMPSHIRE_MIN_XC 0
  42 #define HAMPSHIRE_MAX_XC 0x1000
  43 #define HAMPSHIRE_MIN_YC 0
  44 #define HAMPSHIRE_MAX_YC 0x1000
  45
  46 #define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
  47 #define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
  48 #define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
  49
  50 /*
  51  * Per-touchscreen data.
  52  */
  53
  54 struct hampshire {
  55         struct input_dev *dev;
  56         struct serio *serio;
  57         int idx;
  58         unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
  59         char phys[32];
  60 };
  61
  62 static void hampshire_process_data(struct hampshire *phampshire)
  63 {
  64         struct input_dev *dev = phampshire->dev;
  65
  66         if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
  67                 input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
  68                 input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
  69                 input_report_key(dev, BTN_TOUCH,
  70                                  HAMPSHIRE_GET_TOUCHED(phampshire->data));
  71                 input_sync(dev);
  72
  73                 phampshire->idx = 0;
  74         }
  75 }
  76
  77 static irqreturn_t hampshire_interrupt(struct serio *serio,
  78                 unsigned char data, unsigned int flags)
  79 {
  80         struct hampshire *phampshire = serio_get_drvdata(serio);
  81
  82         phampshire->data[phampshire->idx] = data;
  83
  84         if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
  85                 hampshire_process_data(phampshire);
  86         else
  87                 dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
  88                         phampshire->data[0]);
  89
  90         return IRQ_HANDLED;
  91 }
  92
  93 static void hampshire_disconnect(struct serio *serio)
  94 {
  95         struct hampshire *phampshire = serio_get_drvdata(serio);
  96
  97         input_get_device(phampshire->dev);
  98         input_unregister_device(phampshire->dev);
  99         serio_close(serio);
 100         serio_set_drvdata(serio, NULL);
 101         input_put_device(phampshire->dev);
 102         kfree(phampshire);
 103 }
 104
 105 /*
 106  * hampshire_connect() is the routine that is called when someone adds a
 107  * new serio device that supports hampshire protocol and registers it as
 108  * an input device. This is usually accomplished using inputattach.
 109  */
 110
 111 static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
 112 {
 113         struct hampshire *phampshire;
 114         struct input_dev *input_dev;
 115         int err;
 116
 117         phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL);
 118         input_dev = input_allocate_device();
 119         if (!phampshire || !input_dev) {
 120                 err = -ENOMEM;
 121                 goto fail1;
 122         }
 123
 124         phampshire->serio = serio;
 125         phampshire->dev = input_dev;
 126         snprintf(phampshire->phys, sizeof(phampshire->phys),
 127                  "%s/input0", serio->phys);
 128
 129         input_dev->name = "Hampshire Serial TouchScreen";
 130         input_dev->phys = phampshire->phys;
 131         input_dev->id.bustype = BUS_RS232;
 132         input_dev->id.vendor = SERIO_HAMPSHIRE;
 133         input_dev->id.product = 0;
 134         input_dev->id.version = 0x0001;
 135         input_dev->dev.parent = &serio->dev;
 136         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 137         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 138         input_set_abs_params(phampshire->dev, ABS_X,
 139                              HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
 140         input_set_abs_params(phampshire->dev, ABS_Y,
 141                              HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
 142
 143         serio_set_drvdata(serio, phampshire);
 144
 145         err = serio_open(serio, drv);
 146         if (err)
 147                 goto fail2;
 148
 149         err = input_register_device(phampshire->dev);
 150         if (err)
 151                 goto fail3;
 152
 153         return 0;
 154
 155  fail3: serio_close(serio);
 156  fail2: serio_set_drvdata(serio, NULL);
 157  fail1: input_free_device(input_dev);
 158         kfree(phampshire);
 159         return err;
 160 }
 161
 162 /*
 163  * The serio driver structure.
 164  */
 165
 166 static struct serio_device_id hampshire_serio_ids[] = {
 167         {
 168                 .type   = SERIO_RS232,
 169                 .proto  = SERIO_HAMPSHIRE,
 170                 .id     = SERIO_ANY,
 171                 .extra  = SERIO_ANY,
 172         },
 173         { 0 }
 174 };
 175
 176 MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
 177
 178 static struct serio_driver hampshire_drv = {
 179         .driver         = {
 180                 .name   = "hampshire",
 181         },
 182         .description    = DRIVER_DESC,
 183         .id_table       = hampshire_serio_ids,
 184         .interrupt      = hampshire_interrupt,
 185         .connect        = hampshire_connect,
 186         .disconnect     = hampshire_disconnect,
 187 };
 188
 189 module_serio_driver(hampshire_drv);