drivers/input/touchscreen/touchit213.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Sahara TouchIT-213 serial touchscreen driver
   4  *
   5  * Copyright (c) 2007-2008 Claudio Nieder <private@claudio.ch>
   6  *
   7  * Based on Touchright driver (drivers/input/touchscreen/touchright.c)
   8  * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com>
   9  * Copyright (c) 2004 Vojtech Pavlik
  10  * and Dan Streetman <ddstreet@ieee.org>
  11  */
  12
  13
  14 #include <linux/errno.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/input.h>
  19 #include <linux/serio.h>
  20
  21 #define DRIVER_DESC     "Sahara TouchIT-213 serial touchscreen driver"
  22
  23 MODULE_AUTHOR("Claudio Nieder <private@claudio.ch>");
  24 MODULE_DESCRIPTION(DRIVER_DESC);
  25 MODULE_LICENSE("GPL");
  26
  27 /*
  28  * Definitions & global arrays.
  29  */
  30
  31 /*
  32  * Data is received through COM1 at 9600bit/s,8bit,no parity in packets
  33  * of 5 byte each.
  34  *
  35  *   +--------+   +--------+   +--------+   +--------+   +--------+
  36  *   |1000000p|   |0xxxxxxx|   |0xxxxxxx|   |0yyyyyyy|   |0yyyyyyy|
  37  *   +--------+   +--------+   +--------+   +--------+   +--------+
  38  *                    MSB          LSB          MSB          LSB
  39  *
  40  * The value of p is 1 as long as the screen is touched and 0 when
  41  * reporting the location where touching stopped, e.g. where the pen was
  42  * lifted from the screen.
  43  *
  44  * When holding the screen in landscape mode as the BIOS text output is
  45  * presented, x is the horizontal axis with values growing from left to
  46  * right and y is the vertical axis with values growing from top to
  47  * bottom.
  48  *
  49  * When holding the screen in portrait mode with the Sahara logo in its
  50  * correct position, x ist the vertical axis with values growing from
  51  * top to bottom and y is the horizontal axis with values growing from
  52  * right to left.
  53  */
  54
  55 #define T213_FORMAT_TOUCH_BIT   0x01
  56 #define T213_FORMAT_STATUS_BYTE 0x80
  57 #define T213_FORMAT_STATUS_MASK ~T213_FORMAT_TOUCH_BIT
  58
  59 /*
  60  * On my Sahara Touch-IT 213 I have observed x values from 0 to 0x7f0
  61  * and y values from 0x1d to 0x7e9, so the actual measurement is
  62  * probably done with an 11 bit precision.
  63  */
  64 #define T213_MIN_XC 0
  65 #define T213_MAX_XC 0x07ff
  66 #define T213_MIN_YC 0
  67 #define T213_MAX_YC 0x07ff
  68
  69 /*
  70  * Per-touchscreen data.
  71  */
  72
  73 struct touchit213 {
  74         struct input_dev *dev;
  75         struct serio *serio;
  76         int idx;
  77         unsigned char csum;
  78         unsigned char data[5];
  79         char phys[32];
  80 };
  81
  82 static irqreturn_t touchit213_interrupt(struct serio *serio,
  83                 unsigned char data, unsigned int flags)
  84 {
  85         struct touchit213 *touchit213 = serio_get_drvdata(serio);
  86         struct input_dev *dev = touchit213->dev;
  87
  88         touchit213->data[touchit213->idx] = data;
  89
  90         switch (touchit213->idx++) {
  91         case 0:
  92                 if ((touchit213->data[0] & T213_FORMAT_STATUS_MASK) !=
  93                                 T213_FORMAT_STATUS_BYTE) {
  94                         pr_debug("unsynchronized data: 0x%02x\n", data);
  95                         touchit213->idx = 0;
  96                 }
  97                 break;
  98
  99         case 4:
 100                 touchit213->idx = 0;
 101                 input_report_abs(dev, ABS_X,
 102                         (touchit213->data[1] << 7) | touchit213->data[2]);
 103                 input_report_abs(dev, ABS_Y,
 104                         (touchit213->data[3] << 7) | touchit213->data[4]);
 105                 input_report_key(dev, BTN_TOUCH,
 106                         touchit213->data[0] & T213_FORMAT_TOUCH_BIT);
 107                 input_sync(dev);
 108                 break;
 109         }
 110
 111         return IRQ_HANDLED;
 112 }
 113
 114 /*
 115  * touchit213_disconnect() is the opposite of touchit213_connect()
 116  */
 117
 118 static void touchit213_disconnect(struct serio *serio)
 119 {
 120         struct touchit213 *touchit213 = serio_get_drvdata(serio);
 121
 122         input_get_device(touchit213->dev);
 123         input_unregister_device(touchit213->dev);
 124         serio_close(serio);
 125         serio_set_drvdata(serio, NULL);
 126         input_put_device(touchit213->dev);
 127         kfree(touchit213);
 128 }
 129
 130 /*
 131  * touchit213_connect() is the routine that is called when someone adds a
 132  * new serio device that supports the Touchright protocol and registers it as
 133  * an input device.
 134  */
 135
 136 static int touchit213_connect(struct serio *serio, struct serio_driver *drv)
 137 {
 138         struct touchit213 *touchit213;
 139         struct input_dev *input_dev;
 140         int err;
 141
 142         touchit213 = kzalloc(sizeof(*touchit213), GFP_KERNEL);
 143         input_dev = input_allocate_device();
 144         if (!touchit213 || !input_dev) {
 145                 err = -ENOMEM;
 146                 goto fail1;
 147         }
 148
 149         touchit213->serio = serio;
 150         touchit213->dev = input_dev;
 151         snprintf(touchit213->phys, sizeof(touchit213->phys),
 152                  "%s/input0", serio->phys);
 153
 154         input_dev->name = "Sahara Touch-iT213 Serial TouchScreen";
 155         input_dev->phys = touchit213->phys;
 156         input_dev->id.bustype = BUS_RS232;
 157         input_dev->id.vendor = SERIO_TOUCHIT213;
 158         input_dev->id.product = 0;
 159         input_dev->id.version = 0x0100;
 160         input_dev->dev.parent = &serio->dev;
 161         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 162         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 163         input_set_abs_params(touchit213->dev, ABS_X,
 164                              T213_MIN_XC, T213_MAX_XC, 0, 0);
 165         input_set_abs_params(touchit213->dev, ABS_Y,
 166                              T213_MIN_YC, T213_MAX_YC, 0, 0);
 167
 168         serio_set_drvdata(serio, touchit213);
 169
 170         err = serio_open(serio, drv);
 171         if (err)
 172                 goto fail2;
 173
 174         err = input_register_device(touchit213->dev);
 175         if (err)
 176                 goto fail3;
 177
 178         return 0;
 179
 180  fail3: serio_close(serio);
 181  fail2: serio_set_drvdata(serio, NULL);
 182  fail1: input_free_device(input_dev);
 183         kfree(touchit213);
 184         return err;
 185 }
 186
 187 /*
 188  * The serio driver structure.
 189  */
 190
 191 static const struct serio_device_id touchit213_serio_ids[] = {
 192         {
 193                 .type   = SERIO_RS232,
 194                 .proto  = SERIO_TOUCHIT213,
 195                 .id     = SERIO_ANY,
 196                 .extra  = SERIO_ANY,
 197         },
 198         { 0 }
 199 };
 200
 201 MODULE_DEVICE_TABLE(serio, touchit213_serio_ids);
 202
 203 static struct serio_driver touchit213_drv = {
 204         .driver         = {
 205                 .name   = "touchit213",
 206         },
 207         .description    = DRIVER_DESC,
 208         .id_table       = touchit213_serio_ids,
 209         .interrupt      = touchit213_interrupt,
 210         .connect        = touchit213_connect,
 211         .disconnect     = touchit213_disconnect,
 212 };
 213
 214 module_serio_driver(touchit213_drv);