drivers/input/touchscreen/touchit213.c

   1 /*
   2  * Sahara TouchIT-213 serial touchscreen driver
   3  *
   4  * Copyright (c) 2007-2008 Claudio Nieder <private@claudio.ch>
   5  *
   6  * Based on Touchright driver (drivers/input/touchscreen/touchright.c)
   7  * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com>
   8  * Copyright (c) 2004 Vojtech Pavlik
   9  * and Dan Streetman <ddstreet@ieee.org>
  10  */
  11
  12 /*
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms of the GNU General Public License version 2 as published
  15  * by the Free Software Foundation.
  16  */
  17
  18 #include <linux/errno.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/input.h>
  23 #include <linux/serio.h>
  24 #include <linux/init.h>
  25
  26 #define DRIVER_DESC     "Sahara TouchIT-213 serial touchscreen driver"
  27
  28 MODULE_AUTHOR("Claudio Nieder <private@claudio.ch>");
  29 MODULE_DESCRIPTION(DRIVER_DESC);
  30 MODULE_LICENSE("GPL");
  31
  32 /*
  33  * Definitions & global arrays.
  34  */
  35
  36 /*
  37  * Data is received through COM1 at 9600bit/s,8bit,no parity in packets
  38  * of 5 byte each.
  39  *
  40  *   +--------+   +--------+   +--------+   +--------+   +--------+
  41  *   |1000000p|   |0xxxxxxx|   |0xxxxxxx|   |0yyyyyyy|   |0yyyyyyy|
  42  *   +--------+   +--------+   +--------+   +--------+   +--------+
  43  *                    MSB          LSB          MSB          LSB
  44  *
  45  * The value of p is 1 as long as the screen is touched and 0 when
  46  * reporting the location where touching stopped, e.g. where the pen was
  47  * lifted from the screen.
  48  *
  49  * When holding the screen in landscape mode as the BIOS text output is
  50  * presented, x is the horizontal axis with values growing from left to
  51  * right and y is the vertical axis with values growing from top to
  52  * bottom.
  53  *
  54  * When holding the screen in portrait mode with the Sahara logo in its
  55  * correct position, x ist the vertical axis with values growing from
  56  * top to bottom and y is the horizontal axis with values growing from
  57  * right to left.
  58  */
  59
  60 #define T213_FORMAT_TOUCH_BIT   0x01
  61 #define T213_FORMAT_STATUS_BYTE 0x80
  62 #define T213_FORMAT_STATUS_MASK ~T213_FORMAT_TOUCH_BIT
  63
  64 /*
  65  * On my Sahara Touch-IT 213 I have observed x values from 0 to 0x7f0
  66  * and y values from 0x1d to 0x7e9, so the actual measurement is
  67  * probably done with an 11 bit precision.
  68  */
  69 #define T213_MIN_XC 0
  70 #define T213_MAX_XC 0x07ff
  71 #define T213_MIN_YC 0
  72 #define T213_MAX_YC 0x07ff
  73
  74 /*
  75  * Per-touchscreen data.
  76  */
  77
  78 struct touchit213 {
  79         struct input_dev *dev;
  80         struct serio *serio;
  81         int idx;
  82         unsigned char csum;
  83         unsigned char data[5];
  84         char phys[32];
  85 };
  86
  87 static irqreturn_t touchit213_interrupt(struct serio *serio,
  88                 unsigned char data, unsigned int flags)
  89 {
  90         struct touchit213 *touchit213 = serio_get_drvdata(serio);
  91         struct input_dev *dev = touchit213->dev;
  92
  93         touchit213->data[touchit213->idx] = data;
  94
  95         switch (touchit213->idx++) {
  96         case 0:
  97                 if ((touchit213->data[0] & T213_FORMAT_STATUS_MASK) !=
  98                                 T213_FORMAT_STATUS_BYTE) {
  99                         pr_debug("unsynchronized data: 0x%02x\n", data);
 100                         touchit213->idx = 0;
 101                 }
 102                 break;
 103
 104         case 4:
 105                 touchit213->idx = 0;
 106                 input_report_abs(dev, ABS_X,
 107                         (touchit213->data[1] << 7) | touchit213->data[2]);
 108                 input_report_abs(dev, ABS_Y,
 109                         (touchit213->data[3] << 7) | touchit213->data[4]);
 110                 input_report_key(dev, BTN_TOUCH,
 111                         touchit213->data[0] & T213_FORMAT_TOUCH_BIT);
 112                 input_sync(dev);
 113                 break;
 114         }
 115
 116         return IRQ_HANDLED;
 117 }
 118
 119 /*
 120  * touchit213_disconnect() is the opposite of touchit213_connect()
 121  */
 122
 123 static void touchit213_disconnect(struct serio *serio)
 124 {
 125         struct touchit213 *touchit213 = serio_get_drvdata(serio);
 126
 127         input_get_device(touchit213->dev);
 128         input_unregister_device(touchit213->dev);
 129         serio_close(serio);
 130         serio_set_drvdata(serio, NULL);
 131         input_put_device(touchit213->dev);
 132         kfree(touchit213);
 133 }
 134
 135 /*
 136  * touchit213_connect() is the routine that is called when someone adds a
 137  * new serio device that supports the Touchright protocol and registers it as
 138  * an input device.
 139  */
 140
 141 static int touchit213_connect(struct serio *serio, struct serio_driver *drv)
 142 {
 143         struct touchit213 *touchit213;
 144         struct input_dev *input_dev;
 145         int err;
 146
 147         touchit213 = kzalloc(sizeof(struct touchit213), GFP_KERNEL);
 148         input_dev = input_allocate_device();
 149         if (!touchit213 || !input_dev) {
 150                 err = -ENOMEM;
 151                 goto fail1;
 152         }
 153
 154         touchit213->serio = serio;
 155         touchit213->dev = input_dev;
 156         snprintf(touchit213->phys, sizeof(touchit213->phys),
 157                  "%s/input0", serio->phys);
 158
 159         input_dev->name = "Sahara Touch-iT213 Serial TouchScreen";
 160         input_dev->phys = touchit213->phys;
 161         input_dev->id.bustype = BUS_RS232;
 162         input_dev->id.vendor = SERIO_TOUCHIT213;
 163         input_dev->id.product = 0;
 164         input_dev->id.version = 0x0100;
 165         input_dev->dev.parent = &serio->dev;
 166         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 167         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 168         input_set_abs_params(touchit213->dev, ABS_X,
 169                              T213_MIN_XC, T213_MAX_XC, 0, 0);
 170         input_set_abs_params(touchit213->dev, ABS_Y,
 171                              T213_MIN_YC, T213_MAX_YC, 0, 0);
 172
 173         serio_set_drvdata(serio, touchit213);
 174
 175         err = serio_open(serio, drv);
 176         if (err)
 177                 goto fail2;
 178
 179         err = input_register_device(touchit213->dev);
 180         if (err)
 181                 goto fail3;
 182
 183         return 0;
 184
 185  fail3: serio_close(serio);
 186  fail2: serio_set_drvdata(serio, NULL);
 187  fail1: input_free_device(input_dev);
 188         kfree(touchit213);
 189         return err;
 190 }
 191
 192 /*
 193  * The serio driver structure.
 194  */
 195
 196 static struct serio_device_id touchit213_serio_ids[] = {
 197         {
 198                 .type   = SERIO_RS232,
 199                 .proto  = SERIO_TOUCHIT213,
 200                 .id     = SERIO_ANY,
 201                 .extra  = SERIO_ANY,
 202         },
 203         { 0 }
 204 };
 205
 206 MODULE_DEVICE_TABLE(serio, touchit213_serio_ids);
 207
 208 static struct serio_driver touchit213_drv = {
 209         .driver         = {
 210                 .name   = "touchit213",
 211         },
 212         .description    = DRIVER_DESC,
 213         .id_table       = touchit213_serio_ids,
 214         .interrupt      = touchit213_interrupt,
 215         .connect        = touchit213_connect,
 216         .disconnect     = touchit213_disconnect,
 217 };
 218
 219 /*
 220  * The functions for inserting/removing us as a module.
 221  */
 222
 223 static int __init touchit213_init(void)
 224 {
 225         return serio_register_driver(&touchit213_drv);
 226 }
 227
 228 static void __exit touchit213_exit(void)
 229 {
 230         serio_unregister_driver(&touchit213_drv);
 231 }
 232
 233 module_init(touchit213_init);
 234 module_exit(touchit213_exit);