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