drivers/input/touchscreen/egalax_ts_serial.c

   1 /*
   2  * EETI Egalax serial touchscreen driver
   3  *
   4  * Copyright (c) 2015 Zoltán Böszörményi <zboszor@pr.hu>
   5  *
   6  * based on the
   7  *
   8  * Hampshire serial touchscreen driver (Copyright (c) 2010 Adam Bennett)
   9  */
  10
  11 /*
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License version 2 as published by
  14  * the Free Software Foundation.
  15  */
  16
  17 #include <linux/errno.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/slab.h>
  21 #include <linux/input.h>
  22 #include <linux/serio.h>
  23
  24 #define DRIVER_DESC     "EETI Egalax serial touchscreen driver"
  25
  26 /*
  27  * Definitions & global arrays.
  28  */
  29
  30 #define EGALAX_FORMAT_MAX_LENGTH        6
  31 #define EGALAX_FORMAT_START_BIT         BIT(7)
  32 #define EGALAX_FORMAT_PRESSURE_BIT      BIT(6)
  33 #define EGALAX_FORMAT_TOUCH_BIT         BIT(0)
  34 #define EGALAX_FORMAT_RESOLUTION_MASK   0x06
  35
  36 #define EGALAX_MIN_XC                   0
  37 #define EGALAX_MAX_XC                   0x4000
  38 #define EGALAX_MIN_YC                   0
  39 #define EGALAX_MAX_YC                   0x4000
  40
  41 /*
  42  * Per-touchscreen data.
  43  */
  44 struct egalax {
  45         struct input_dev *input;
  46         struct serio *serio;
  47         int idx;
  48         u8 data[EGALAX_FORMAT_MAX_LENGTH];
  49         char phys[32];
  50 };
  51
  52 static void egalax_process_data(struct egalax *egalax)
  53 {
  54         struct input_dev *dev = egalax->input;
  55         u8 *data = egalax->data;
  56         u16 x, y;
  57         u8 shift;
  58         u8 mask;
  59
  60         shift = 3 - ((data[0] & EGALAX_FORMAT_RESOLUTION_MASK) >> 1);
  61         mask = 0xff >> (shift + 1);
  62
  63         x = (((u16)(data[1] & mask) << 7) | (data[2] & 0x7f)) << shift;
  64         y = (((u16)(data[3] & mask) << 7) | (data[4] & 0x7f)) << shift;
  65
  66         input_report_key(dev, BTN_TOUCH, data[0] & EGALAX_FORMAT_TOUCH_BIT);
  67         input_report_abs(dev, ABS_X, x);
  68         input_report_abs(dev, ABS_Y, y);
  69         input_sync(dev);
  70 }
  71
  72 static irqreturn_t egalax_interrupt(struct serio *serio,
  73                                     unsigned char data, unsigned int flags)
  74 {
  75         struct egalax *egalax = serio_get_drvdata(serio);
  76         int pkt_len;
  77
  78         egalax->data[egalax->idx++] = data;
  79
  80         if (likely(egalax->data[0] & EGALAX_FORMAT_START_BIT)) {
  81                 pkt_len = egalax->data[0] & EGALAX_FORMAT_PRESSURE_BIT ? 6 : 5;
  82                 if (pkt_len == egalax->idx) {
  83                         egalax_process_data(egalax);
  84                         egalax->idx = 0;
  85                 }
  86         } else {
  87                 dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
  88                         egalax->data[0]);
  89                 egalax->idx = 0;
  90         }
  91
  92         return IRQ_HANDLED;
  93 }
  94
  95 /*
  96  * egalax_connect() is the routine that is called when someone adds a
  97  * new serio device that supports egalax protocol and registers it as
  98  * an input device. This is usually accomplished using inputattach.
  99  */
 100 static int egalax_connect(struct serio *serio, struct serio_driver *drv)
 101 {
 102         struct egalax *egalax;
 103         struct input_dev *input_dev;
 104         int error;
 105
 106         egalax = kzalloc(sizeof(struct egalax), GFP_KERNEL);
 107         input_dev = input_allocate_device();
 108         if (!egalax || !input_dev) {
 109                 error = -ENOMEM;
 110                 goto err_free_mem;
 111         }
 112
 113         egalax->serio = serio;
 114         egalax->input = input_dev;
 115         snprintf(egalax->phys, sizeof(egalax->phys),
 116                  "%s/input0", serio->phys);
 117
 118         input_dev->name = "EETI eGalaxTouch Serial TouchScreen";
 119         input_dev->phys = egalax->phys;
 120         input_dev->id.bustype = BUS_RS232;
 121         input_dev->id.vendor = SERIO_EGALAX;
 122         input_dev->id.product = 0;
 123         input_dev->id.version = 0x0001;
 124         input_dev->dev.parent = &serio->dev;
 125
 126         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 127         input_set_abs_params(input_dev, ABS_X,
 128                              EGALAX_MIN_XC, EGALAX_MAX_XC, 0, 0);
 129         input_set_abs_params(input_dev, ABS_Y,
 130                              EGALAX_MIN_YC, EGALAX_MAX_YC, 0, 0);
 131
 132         serio_set_drvdata(serio, egalax);
 133
 134         error = serio_open(serio, drv);
 135         if (error)
 136                 goto err_reset_drvdata;
 137
 138         error = input_register_device(input_dev);
 139         if (error)
 140                 goto err_close_serio;
 141
 142         return 0;
 143
 144 err_close_serio:
 145         serio_close(serio);
 146 err_reset_drvdata:
 147         serio_set_drvdata(serio, NULL);
 148 err_free_mem:
 149         input_free_device(input_dev);
 150         kfree(egalax);
 151         return error;
 152 }
 153
 154 static void egalax_disconnect(struct serio *serio)
 155 {
 156         struct egalax *egalax = serio_get_drvdata(serio);
 157
 158         serio_close(serio);
 159         serio_set_drvdata(serio, NULL);
 160         input_unregister_device(egalax->input);
 161         kfree(egalax);
 162 }
 163
 164 /*
 165  * The serio driver structure.
 166  */
 167
 168 static const struct serio_device_id egalax_serio_ids[] = {
 169         {
 170                 .type   = SERIO_RS232,
 171                 .proto  = SERIO_EGALAX,
 172                 .id     = SERIO_ANY,
 173                 .extra  = SERIO_ANY,
 174         },
 175         { 0 }
 176 };
 177
 178 MODULE_DEVICE_TABLE(serio, egalax_serio_ids);
 179
 180 static struct serio_driver egalax_drv = {
 181         .driver         = {
 182                 .name   = "egalax",
 183         },
 184         .description    = DRIVER_DESC,
 185         .id_table       = egalax_serio_ids,
 186         .interrupt      = egalax_interrupt,
 187         .connect        = egalax_connect,
 188         .disconnect     = egalax_disconnect,
 189 };
 190 module_serio_driver(egalax_drv);
 191
 192 MODULE_AUTHOR("Zoltán Böszörményi <zboszor@pr.hu>");
 193 MODULE_DESCRIPTION(DRIVER_DESC);
 194 MODULE_LICENSE("GPL v2");