LXR qemu/hw/input/ads7846.c

   1/*
   2 * TI ADS7846 / TSC2046 chip emulation.
   3 *
   4 * Copyright (c) 2006 Openedhand Ltd.
   5 * Written by Andrzej Zaborowski <balrog@zabor.org>
   6 *
   7 * This code is licensed under the GNU GPL v2.
   8 *
   9 * Contributions after 2012-01-13 are licensed under the terms of the
  10 * GNU GPL, version 2 or (at your option) any later version.
  11 */
  12
  13#include "qemu/osdep.h"
  14#include "hw/irq.h"
  15#include "hw/ssi/ssi.h"
  16#include "migration/vmstate.h"
  17#include "qemu/module.h"
  18#include "ui/console.h"
  19#include "qom/object.h"
  20
  21struct ADS7846State {
  22    SSIPeripheral ssidev;
  23    qemu_irq interrupt;
  24
  25    int input[8];
  26    int pressure;
  27    int noise;
  28
  29    int cycle;
  30    int output;
  31};
  32
  33#define TYPE_ADS7846 "ads7846"
  34OBJECT_DECLARE_SIMPLE_TYPE(ADS7846State, ADS7846)
  35
  36/* Control-byte bitfields */
  37#define CB_PD0          (1 << 0)
  38#define CB_PD1          (1 << 1)
  39#define CB_SER          (1 << 2)
  40#define CB_MODE         (1 << 3)
  41#define CB_A0           (1 << 4)
  42#define CB_A1           (1 << 5)
  43#define CB_A2           (1 << 6)
  44#define CB_START        (1 << 7)
  45
  46#define X_AXIS_DMAX     3470
  47#define X_AXIS_MIN      290
  48#define Y_AXIS_DMAX     3450
  49#define Y_AXIS_MIN      200
  50
  51#define ADS_VBAT        2000
  52#define ADS_VAUX        2000
  53#define ADS_TEMP0       2000
  54#define ADS_TEMP1       3000
  55#define ADS_XPOS(x, y)  (X_AXIS_MIN + ((X_AXIS_DMAX * (x)) >> 15))
  56#define ADS_YPOS(x, y)  (Y_AXIS_MIN + ((Y_AXIS_DMAX * (y)) >> 15))
  57#define ADS_Z1POS(x, y) 600
  58#define ADS_Z2POS(x, y) (600 + 6000 / ADS_XPOS(x, y))
  59
  60static void ads7846_int_update(ADS7846State *s)
  61{
  62    if (s->interrupt)
  63        qemu_set_irq(s->interrupt, s->pressure == 0);
  64}
  65
  66static uint32_t ads7846_transfer(SSIPeripheral *dev, uint32_t value)
  67{
  68    ADS7846State *s = ADS7846(dev);
  69
  70    switch (s->cycle ++) {
  71    case 0:
  72        if (!(value & CB_START)) {
  73            s->cycle = 0;
  74            break;
  75        }
  76
  77        s->output = s->input[(value >> 4) & 7];
  78
  79        /* Imitate the ADC noise, some drivers expect this.  */
  80        s->noise = (s->noise + 3) & 7;
  81        switch ((value >> 4) & 7) {
  82        case 1: s->output += s->noise ^ 2; break;
  83        case 3: s->output += s->noise ^ 0; break;
  84        case 4: s->output += s->noise ^ 7; break;
  85        case 5: s->output += s->noise ^ 5; break;
  86        }
  87
  88        if (value & CB_MODE)
  89            s->output >>= 4;    /* 8 bits instead of 12 */
  90
  91        break;
  92    case 1:
  93        s->cycle = 0;
  94        break;
  95    }
  96    return s->output;
  97}
  98
  99static void ads7846_ts_event(void *opaque,
 100                int x, int y, int z, int buttons_state)
 101{
 102    ADS7846State *s = opaque;
 103
 104    if (buttons_state) {
 105        x = 0x7fff - x;
 106        s->input[1] = ADS_XPOS(x, y);
 107        s->input[3] = ADS_Z1POS(x, y);
 108        s->input[4] = ADS_Z2POS(x, y);
 109        s->input[5] = ADS_YPOS(x, y);
 110    }
 111
 112    if (s->pressure == !buttons_state) {
 113        s->pressure = !!buttons_state;
 114
 115        ads7846_int_update(s);
 116    }
 117}
 118
 119static int ads7856_post_load(void *opaque, int version_id)
 120{
 121    ADS7846State *s = opaque;
 122
 123    s->pressure = 0;
 124    ads7846_int_update(s);
 125    return 0;
 126}
 127
 128static const VMStateDescription vmstate_ads7846 = {
 129    .name = "ads7846",
 130    .version_id = 1,
 131    .minimum_version_id = 1,
 132    .post_load = ads7856_post_load,
 133    .fields = (VMStateField[]) {
 134        VMSTATE_SSI_PERIPHERAL(ssidev, ADS7846State),
 135        VMSTATE_INT32_ARRAY(input, ADS7846State, 8),
 136        VMSTATE_INT32(noise, ADS7846State),
 137        VMSTATE_INT32(cycle, ADS7846State),
 138        VMSTATE_INT32(output, ADS7846State),
 139        VMSTATE_END_OF_LIST()
 140    }
 141};
 142
 143static void ads7846_realize(SSIPeripheral *d, Error **errp)
 144{
 145    DeviceState *dev = DEVICE(d);
 146    ADS7846State *s = ADS7846(d);
 147
 148    qdev_init_gpio_out(dev, &s->interrupt, 1);
 149
 150    s->input[0] = ADS_TEMP0;    /* TEMP0 */
 151    s->input[2] = ADS_VBAT;     /* VBAT */
 152    s->input[6] = ADS_VAUX;     /* VAUX */
 153    s->input[7] = ADS_TEMP1;    /* TEMP1 */
 154
 155    /* We want absolute coordinates */
 156    qemu_add_mouse_event_handler(ads7846_ts_event, s, 1,
 157                    "QEMU ADS7846-driven Touchscreen");
 158
 159    ads7846_int_update(s);
 160
 161    vmstate_register(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_ads7846, s);
 162}
 163
 164static void ads7846_class_init(ObjectClass *klass, void *data)
 165{
 166    DeviceClass *dc = DEVICE_CLASS(klass);
 167    SSIPeripheralClass *k = SSI_PERIPHERAL_CLASS(klass);
 168
 169    k->realize = ads7846_realize;
 170    k->transfer = ads7846_transfer;
 171    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 172}
 173
 174static const TypeInfo ads7846_info = {
 175    .name          = TYPE_ADS7846,
 176    .parent        = TYPE_SSI_PERIPHERAL,
 177    .instance_size = sizeof(ADS7846State),
 178    .class_init    = ads7846_class_init,
 179};
 180
 181static void ads7846_register_types(void)
 182{
 183    type_register_static(&ads7846_info);
 184}
 185
 186type_init(ads7846_register_types)
 187