LXR qemu/hw/display/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
  20typedef struct {
  21    SSISlave ssidev;
  22    qemu_irq interrupt;
  23
  24    int input[8];
  25    int pressure;
  26    int noise;
  27
  28    int cycle;
  29    int output;
  30} ADS7846State;
  31
  32/* Control-byte bitfields */
  33#define CB_PD0          (1 << 0)
  34#define CB_PD1          (1 << 1)
  35#define CB_SER          (1 << 2)
  36#define CB_MODE         (1 << 3)
  37#define CB_A0           (1 << 4)
  38#define CB_A1           (1 << 5)
  39#define CB_A2           (1 << 6)
  40#define CB_START        (1 << 7)
  41
  42#define X_AXIS_DMAX     3470
  43#define X_AXIS_MIN      290
  44#define Y_AXIS_DMAX     3450
  45#define Y_AXIS_MIN      200
  46
  47#define ADS_VBAT        2000
  48#define ADS_VAUX        2000
  49#define ADS_TEMP0       2000
  50#define ADS_TEMP1       3000
  51#define ADS_XPOS(x, y)  (X_AXIS_MIN + ((X_AXIS_DMAX * (x)) >> 15))
  52#define ADS_YPOS(x, y)  (Y_AXIS_MIN + ((Y_AXIS_DMAX * (y)) >> 15))
  53#define ADS_Z1POS(x, y) 600
  54#define ADS_Z2POS(x, y) (600 + 6000 / ADS_XPOS(x, y))
  55
  56static void ads7846_int_update(ADS7846State *s)
  57{
  58    if (s->interrupt)
  59        qemu_set_irq(s->interrupt, s->pressure == 0);
  60}
  61
  62static uint32_t ads7846_transfer(SSISlave *dev, uint32_t value)
  63{
  64    ADS7846State *s = FROM_SSI_SLAVE(ADS7846State, dev);
  65
  66    switch (s->cycle ++) {
  67    case 0:
  68        if (!(value & CB_START)) {
  69            s->cycle = 0;
  70            break;
  71        }
  72
  73        s->output = s->input[(value >> 4) & 7];
  74
  75        /* Imitate the ADC noise, some drivers expect this.  */
  76        s->noise = (s->noise + 3) & 7;
  77        switch ((value >> 4) & 7) {
  78        case 1: s->output += s->noise ^ 2; break;
  79        case 3: s->output += s->noise ^ 0; break;
  80        case 4: s->output += s->noise ^ 7; break;
  81        case 5: s->output += s->noise ^ 5; break;
  82        }
  83
  84        if (value & CB_MODE)
  85            s->output >>= 4;    /* 8 bits instead of 12 */
  86
  87        break;
  88    case 1:
  89        s->cycle = 0;
  90        break;
  91    }
  92    return s->output;
  93}
  94
  95static void ads7846_ts_event(void *opaque,
  96                int x, int y, int z, int buttons_state)
  97{
  98    ADS7846State *s = opaque;
  99
 100    if (buttons_state) {
 101        x = 0x7fff - x;
 102        s->input[1] = ADS_XPOS(x, y);
 103        s->input[3] = ADS_Z1POS(x, y);
 104        s->input[4] = ADS_Z2POS(x, y);
 105        s->input[5] = ADS_YPOS(x, y);
 106    }
 107
 108    if (s->pressure == !buttons_state) {
 109        s->pressure = !!buttons_state;
 110
 111        ads7846_int_update(s);
 112    }
 113}
 114
 115static int ads7856_post_load(void *opaque, int version_id)
 116{
 117    ADS7846State *s = opaque;
 118
 119    s->pressure = 0;
 120    ads7846_int_update(s);
 121    return 0;
 122}
 123
 124static const VMStateDescription vmstate_ads7846 = {
 125    .name = "ads7846",
 126    .version_id = 1,
 127    .minimum_version_id = 1,
 128    .post_load = ads7856_post_load,
 129    .fields = (VMStateField[]) {
 130        VMSTATE_SSI_SLAVE(ssidev, ADS7846State),
 131        VMSTATE_INT32_ARRAY(input, ADS7846State, 8),
 132        VMSTATE_INT32(noise, ADS7846State),
 133        VMSTATE_INT32(cycle, ADS7846State),
 134        VMSTATE_INT32(output, ADS7846State),
 135        VMSTATE_END_OF_LIST()
 136    }
 137};
 138
 139static void ads7846_realize(SSISlave *d, Error **errp)
 140{
 141    DeviceState *dev = DEVICE(d);
 142    ADS7846State *s = FROM_SSI_SLAVE(ADS7846State, d);
 143
 144    qdev_init_gpio_out(dev, &s->interrupt, 1);
 145
 146    s->input[0] = ADS_TEMP0;    /* TEMP0 */
 147    s->input[2] = ADS_VBAT;     /* VBAT */
 148    s->input[6] = ADS_VAUX;     /* VAUX */
 149    s->input[7] = ADS_TEMP1;    /* TEMP1 */
 150
 151    /* We want absolute coordinates */
 152    qemu_add_mouse_event_handler(ads7846_ts_event, s, 1,
 153                    "QEMU ADS7846-driven Touchscreen");
 154
 155    ads7846_int_update(s);
 156
 157    vmstate_register(NULL, -1, &vmstate_ads7846, s);
 158}
 159
 160static void ads7846_class_init(ObjectClass *klass, void *data)
 161{
 162    SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
 163
 164    k->realize = ads7846_realize;
 165    k->transfer = ads7846_transfer;
 166}
 167
 168static const TypeInfo ads7846_info = {
 169    .name          = "ads7846",
 170    .parent        = TYPE_SSI_SLAVE,
 171    .instance_size = sizeof(ADS7846State),
 172    .class_init    = ads7846_class_init,
 173};
 174
 175static void ads7846_register_types(void)
 176{
 177    type_register_static(&ads7846_info);
 178}
 179
 180type_init(ads7846_register_types)
 181