drivers/input/touchscreen/tsc40.c

   1 /*
   2  * TSC-40 serial touchscreen driver. It should be compatible with
   3  * TSC-10 and 25.
   4  *
   5  * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
   6  * License: GPLv2 as published by the FSF.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/input.h>
  13 #include <linux/serio.h>
  14 #include <linux/init.h>
  15
  16 #define PACKET_LENGTH  5
  17 struct tsc_ser {
  18         struct input_dev *dev;
  19         struct serio *serio;
  20         u32 idx;
  21         unsigned char data[PACKET_LENGTH];
  22         char phys[32];
  23 };
  24
  25 static void tsc_process_data(struct tsc_ser *ptsc)
  26 {
  27         struct input_dev *dev = ptsc->dev;
  28         u8 *data = ptsc->data;
  29         u32 x;
  30         u32 y;
  31
  32         x = ((data[1] & 0x03) << 8) | data[2];
  33         y = ((data[3] & 0x03) << 8) | data[4];
  34
  35         input_report_abs(dev, ABS_X, x);
  36         input_report_abs(dev, ABS_Y, y);
  37         input_report_key(dev, BTN_TOUCH, 1);
  38
  39         input_sync(dev);
  40 }
  41
  42 static irqreturn_t tsc_interrupt(struct serio *serio,
  43                 unsigned char data, unsigned int flags)
  44 {
  45         struct tsc_ser *ptsc = serio_get_drvdata(serio);
  46         struct input_dev *dev = ptsc->dev;
  47
  48         ptsc->data[ptsc->idx] = data;
  49         switch (ptsc->idx++) {
  50         case 0:
  51                 if (unlikely((data & 0x3e) != 0x10)) {
  52                         dev_dbg(&serio->dev,
  53                                 "unsynchronized packet start (0x%02x)\n", data);
  54                         ptsc->idx = 0;
  55                 } else if (!(data & 0x01)) {
  56                         input_report_key(dev, BTN_TOUCH, 0);
  57                         input_sync(dev);
  58                         ptsc->idx = 0;
  59                 }
  60                 break;
  61
  62         case 1:
  63         case 3:
  64                 if (unlikely(data & 0xfc)) {
  65                         dev_dbg(&serio->dev,
  66                                 "unsynchronized data 0x%02x at offset %d\n",
  67                                 data, ptsc->idx - 1);
  68                         ptsc->idx = 0;
  69                 }
  70                 break;
  71
  72         case 4:
  73                 tsc_process_data(ptsc);
  74                 ptsc->idx = 0;
  75                 break;
  76         }
  77
  78         return IRQ_HANDLED;
  79 }
  80
  81 static int tsc_connect(struct serio *serio, struct serio_driver *drv)
  82 {
  83         struct tsc_ser *ptsc;
  84         struct input_dev *input_dev;
  85         int error;
  86
  87         ptsc = kzalloc(sizeof(struct tsc_ser), GFP_KERNEL);
  88         input_dev = input_allocate_device();
  89         if (!ptsc || !input_dev) {
  90                 error = -ENOMEM;
  91                 goto fail1;
  92         }
  93
  94         ptsc->serio = serio;
  95         ptsc->dev = input_dev;
  96         snprintf(ptsc->phys, sizeof(ptsc->phys), "%s/input0", serio->phys);
  97
  98         input_dev->name = "TSC-10/25/40 Serial TouchScreen";
  99         input_dev->phys = ptsc->phys;
 100         input_dev->id.bustype = BUS_RS232;
 101         input_dev->id.vendor = SERIO_TSC40;
 102         input_dev->id.product = 40;
 103         input_dev->id.version = 0x0001;
 104         input_dev->dev.parent = &serio->dev;
 105
 106         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 107         __set_bit(BTN_TOUCH, input_dev->keybit);
 108         input_set_abs_params(ptsc->dev, ABS_X, 0, 0x3ff, 0, 0);
 109         input_set_abs_params(ptsc->dev, ABS_Y, 0, 0x3ff, 0, 0);
 110
 111         serio_set_drvdata(serio, ptsc);
 112
 113         error = serio_open(serio, drv);
 114         if (error)
 115                 goto fail2;
 116
 117         error = input_register_device(ptsc->dev);
 118         if (error)
 119                 goto fail3;
 120
 121         return 0;
 122
 123 fail3:
 124         serio_close(serio);
 125 fail2:
 126         serio_set_drvdata(serio, NULL);
 127 fail1:
 128         input_free_device(input_dev);
 129         kfree(ptsc);
 130         return error;
 131 }
 132
 133 static void tsc_disconnect(struct serio *serio)
 134 {
 135         struct tsc_ser *ptsc = serio_get_drvdata(serio);
 136
 137         serio_close(serio);
 138
 139         input_unregister_device(ptsc->dev);
 140         kfree(ptsc);
 141
 142         serio_set_drvdata(serio, NULL);
 143 }
 144
 145 static struct serio_device_id tsc_serio_ids[] = {
 146         {
 147                 .type   = SERIO_RS232,
 148                 .proto  = SERIO_TSC40,
 149                 .id     = SERIO_ANY,
 150                 .extra  = SERIO_ANY,
 151         },
 152         { 0 }
 153 };
 154 MODULE_DEVICE_TABLE(serio, tsc_serio_ids);
 155
 156 #define DRIVER_DESC    "TSC-10/25/40 serial touchscreen driver"
 157
 158 static struct serio_driver tsc_drv = {
 159         .driver = {
 160                 .name   = "tsc40",
 161         },
 162         .description    = DRIVER_DESC,
 163         .id_table       = tsc_serio_ids,
 164         .interrupt      = tsc_interrupt,
 165         .connect        = tsc_connect,
 166         .disconnect     = tsc_disconnect,
 167 };
 168
 169 module_serio_driver(tsc_drv);
 170
 171 MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>");
 172 MODULE_DESCRIPTION(DRIVER_DESC);
 173 MODULE_LICENSE("GPL v2");