drivers/input/touchscreen/fujitsu_ts.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Fujitsu serial touchscreen driver
   4  *
   5  * Copyright (c) Dmitry Torokhov <dtor@mail.ru>
   6  */
   7
   8
   9 #include <linux/errno.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/input.h>
  14 #include <linux/serio.h>
  15
  16 #define DRIVER_DESC     "Fujitsu serial touchscreen driver"
  17
  18 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
  19 MODULE_DESCRIPTION(DRIVER_DESC);
  20 MODULE_LICENSE("GPL");
  21
  22 #define FUJITSU_LENGTH 5
  23
  24 /*
  25  * Per-touchscreen data.
  26  */
  27 struct fujitsu {
  28         struct input_dev *dev;
  29         struct serio *serio;
  30         int idx;
  31         unsigned char data[FUJITSU_LENGTH];
  32         char phys[32];
  33 };
  34
  35 /*
  36  * Decode serial data (5 bytes per packet)
  37  * First byte
  38  * 1 C 0 0 R S S S
  39  * Where C is 1 while in calibration mode (which we don't use)
  40  * R is 1 when no coordinate corection was done.
  41  * S are button state
  42  */
  43 static irqreturn_t fujitsu_interrupt(struct serio *serio,
  44                                      unsigned char data, unsigned int flags)
  45 {
  46         struct fujitsu *fujitsu = serio_get_drvdata(serio);
  47         struct input_dev *dev = fujitsu->dev;
  48
  49         if (fujitsu->idx == 0) {
  50                 /* resync skip until start of frame */
  51                 if ((data & 0xf0) != 0x80)
  52                         return IRQ_HANDLED;
  53         } else {
  54                 /* resync skip garbage */
  55                 if (data & 0x80) {
  56                         fujitsu->idx = 0;
  57                         return IRQ_HANDLED;
  58                 }
  59         }
  60
  61         fujitsu->data[fujitsu->idx++] = data;
  62         if (fujitsu->idx == FUJITSU_LENGTH) {
  63                 input_report_abs(dev, ABS_X,
  64                                  (fujitsu->data[2] << 7) | fujitsu->data[1]);
  65                 input_report_abs(dev, ABS_Y,
  66                                  (fujitsu->data[4] << 7) | fujitsu->data[3]);
  67                 input_report_key(dev, BTN_TOUCH,
  68                                  (fujitsu->data[0] & 0x03) != 2);
  69                 input_sync(dev);
  70                 fujitsu->idx = 0;
  71         }
  72
  73         return IRQ_HANDLED;
  74 }
  75
  76 /*
  77  * fujitsu_disconnect() is the opposite of fujitsu_connect()
  78  */
  79 static void fujitsu_disconnect(struct serio *serio)
  80 {
  81         struct fujitsu *fujitsu = serio_get_drvdata(serio);
  82
  83         input_get_device(fujitsu->dev);
  84         input_unregister_device(fujitsu->dev);
  85         serio_close(serio);
  86         serio_set_drvdata(serio, NULL);
  87         input_put_device(fujitsu->dev);
  88         kfree(fujitsu);
  89 }
  90
  91 /*
  92  * fujitsu_connect() is the routine that is called when someone adds a
  93  * new serio device that supports the Fujitsu protocol and registers it
  94  * as input device.
  95  */
  96 static int fujitsu_connect(struct serio *serio, struct serio_driver *drv)
  97 {
  98         struct fujitsu *fujitsu;
  99         struct input_dev *input_dev;
 100         int err;
 101
 102         fujitsu = kzalloc(sizeof(*fujitsu), GFP_KERNEL);
 103         input_dev = input_allocate_device();
 104         if (!fujitsu || !input_dev) {
 105                 err = -ENOMEM;
 106                 goto fail1;
 107         }
 108
 109         fujitsu->serio = serio;
 110         fujitsu->dev = input_dev;
 111         snprintf(fujitsu->phys, sizeof(fujitsu->phys),
 112                  "%s/input0", serio->phys);
 113
 114         input_dev->name = "Fujitsu Serial Touchscreen";
 115         input_dev->phys = fujitsu->phys;
 116         input_dev->id.bustype = BUS_RS232;
 117         input_dev->id.vendor = SERIO_FUJITSU;
 118         input_dev->id.product = 0;
 119         input_dev->id.version = 0x0100;
 120         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 121         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 122
 123         input_set_abs_params(input_dev, ABS_X, 0, 4096, 0, 0);
 124         input_set_abs_params(input_dev, ABS_Y, 0, 4096, 0, 0);
 125         serio_set_drvdata(serio, fujitsu);
 126
 127         err = serio_open(serio, drv);
 128         if (err)
 129                 goto fail2;
 130
 131         err = input_register_device(fujitsu->dev);
 132         if (err)
 133                 goto fail3;
 134
 135         return 0;
 136
 137  fail3:
 138         serio_close(serio);
 139  fail2:
 140         serio_set_drvdata(serio, NULL);
 141  fail1:
 142         input_free_device(input_dev);
 143         kfree(fujitsu);
 144         return err;
 145 }
 146
 147 /*
 148  * The serio driver structure.
 149  */
 150 static const struct serio_device_id fujitsu_serio_ids[] = {
 151         {
 152                 .type   = SERIO_RS232,
 153                 .proto  = SERIO_FUJITSU,
 154                 .id     = SERIO_ANY,
 155                 .extra  = SERIO_ANY,
 156         },
 157         { 0 }
 158 };
 159
 160 MODULE_DEVICE_TABLE(serio, fujitsu_serio_ids);
 161
 162 static struct serio_driver fujitsu_drv = {
 163         .driver         = {
 164                 .name   = "fujitsu_ts",
 165         },
 166         .description    = DRIVER_DESC,
 167         .id_table       = fujitsu_serio_ids,
 168         .interrupt      = fujitsu_interrupt,
 169         .connect        = fujitsu_connect,
 170         .disconnect     = fujitsu_disconnect,
 171 };
 172
 173 module_serio_driver(fujitsu_drv);