Archipelago » qemu

/*

 * TI ADS7846 / TSC2046 chip emulation.

 *

 * Copyright (c) 2006 Openedhand Ltd.

 * Written by Andrzej Zaborowski <balrog@zabor.org>

 *

 * This code is licensed under the GNU GPL v2.

 *

 * Contributions after 2012-01-13 are licensed under the terms of the

 * GNU GPL, version 2 or (at your option) any later version.

 */

#include "ssi.h"

#include "console.h"

typedef struct {

    SSISlave ssidev;

    qemu_irq interrupt;

    int input[8];

    int pressure;

    int noise;

    int cycle;

    int output;

} ADS7846State;

/* Control-byte bitfields */

#define CB_PD0                (1 << 0)

#define CB_PD1                (1 << 1)

#define CB_SER                (1 << 2)

#define CB_MODE                (1 << 3)

#define CB_A0                (1 << 4)

#define CB_A1                (1 << 5)

#define CB_A2                (1 << 6)

#define CB_START        (1 << 7)

#define X_AXIS_DMAX        3470

#define X_AXIS_MIN        290

#define Y_AXIS_DMAX        3450

#define Y_AXIS_MIN        200

#define ADS_VBAT        2000

#define ADS_VAUX        2000

#define ADS_TEMP0        2000

#define ADS_TEMP1        3000

#define ADS_XPOS(x, y)        (X_AXIS_MIN + ((X_AXIS_DMAX * (x)) >> 15))

#define ADS_YPOS(x, y)        (Y_AXIS_MIN + ((Y_AXIS_DMAX * (y)) >> 15))

#define ADS_Z1POS(x, y)        600

#define ADS_Z2POS(x, y)        (600 + 6000 / ADS_XPOS(x, y))

static void ads7846_int_update(ADS7846State *s)

{

    if (s->interrupt)

        qemu_set_irq(s->interrupt, s->pressure == 0);

}

static uint32_t ads7846_transfer(SSISlave *dev, uint32_t value)

{

    ADS7846State *s = FROM_SSI_SLAVE(ADS7846State, dev);

    switch (s->cycle ++) {

    case 0:

        if (!(value & CB_START)) {

            s->cycle = 0;

            break;

        }

        s->output = s->input[(value >> 4) & 7];

        /* Imitate the ADC noise, some drivers expect this.  */

        s->noise = (s->noise + 3) & 7;

        switch ((value >> 4) & 7) {

        case 1: s->output += s->noise ^ 2; break;

        case 3: s->output += s->noise ^ 0; break;

        case 4: s->output += s->noise ^ 7; break;

        case 5: s->output += s->noise ^ 5; break;

        }

        if (value & CB_MODE)

            s->output >>= 4;        /* 8 bits instead of 12 */

        break;

    case 1:

        s->cycle = 0;

        break;

    }

    return s->output;

}

static void ads7846_ts_event(void *opaque,

                int x, int y, int z, int buttons_state)

{

    ADS7846State *s = opaque;

    if (buttons_state) {

        x = 0x7fff - x;

        s->input[1] = ADS_XPOS(x, y);

        s->input[3] = ADS_Z1POS(x, y);

        s->input[4] = ADS_Z2POS(x, y);

        s->input[5] = ADS_YPOS(x, y);

    }

    if (s->pressure == !buttons_state) {

        s->pressure = !!buttons_state;

        ads7846_int_update(s);

    }

}

static int ads7856_post_load(void *opaque, int version_id)

{

    ADS7846State *s = opaque;

    s->pressure = 0;

    ads7846_int_update(s);

    return 0;

}

static const VMStateDescription vmstate_ads7846 = {

    .name = "ads7846",

    .version_id = 0,

    .minimum_version_id = 0,

    .minimum_version_id_old = 0,

    .post_load = ads7856_post_load,

    .fields      = (VMStateField[]) {

        VMSTATE_INT32_ARRAY(input, ADS7846State, 8),

        VMSTATE_INT32(noise, ADS7846State),

        VMSTATE_INT32(cycle, ADS7846State),

        VMSTATE_INT32(output, ADS7846State),

        VMSTATE_END_OF_LIST()

    }

};

static int ads7846_init(SSISlave *dev)

{

    ADS7846State *s = FROM_SSI_SLAVE(ADS7846State, dev);

    qdev_init_gpio_out(&dev->qdev, &s->interrupt, 1);

    s->input[0] = ADS_TEMP0;        /* TEMP0 */

    s->input[2] = ADS_VBAT;        /* VBAT */

    s->input[6] = ADS_VAUX;        /* VAUX */

    s->input[7] = ADS_TEMP1;        /* TEMP1 */

    /* We want absolute coordinates */

    qemu_add_mouse_event_handler(ads7846_ts_event, s, 1,

                    "QEMU ADS7846-driven Touchscreen");

    ads7846_int_update(s);

    vmstate_register(NULL, -1, &vmstate_ads7846, s);

    return 0;

}

static void ads7846_class_init(ObjectClass *klass, void *data)

{

    SSISlaveClass *k = SSI_SLAVE_CLASS(klass);

    k->init = ads7846_init;

    k->transfer = ads7846_transfer;

}

static TypeInfo ads7846_info = {

    .name          = "ads7846",

    .parent        = TYPE_SSI_SLAVE,

    .instance_size = sizeof(ADS7846State),

    .class_init    = ads7846_class_init,

};

static void ads7846_register_types(void)

{

    type_register_static(&ads7846_info);

}

type_init(ads7846_register_types)