/*

 * MAX7310 8-port GPIO expansion chip.

 *

 * Copyright (c) 2006 Openedhand Ltd.

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

 *

 * This file is licensed under GNU GPL.

 */

#include "hw.h"

#include "i2c.h"

struct max7310_s {

    i2c_slave i2c;

    int i2c_command_byte;

    int len;

    uint8_t level;

    uint8_t direction;

    uint8_t polarity;

    uint8_t status;

    uint8_t command;

    qemu_irq handler[8];

    qemu_irq *gpio_in;

};

void max7310_reset(i2c_slave *i2c)

{

    struct max7310_s *s = (struct max7310_s *) i2c;

    s->level &= s->direction;

    s->direction = 0xff;

    s->polarity = 0xf0;

    s->status = 0x01;

    s->command = 0x00;

}

static int max7310_rx(i2c_slave *i2c)

{

    struct max7310_s *s = (struct max7310_s *) i2c;

    switch (s->command) {

    case 0x00:	/* Input port */

        return s->level ^ s->polarity;

        break;

    case 0x01:	/* Output port */

        return s->level & ~s->direction;

        break;

    case 0x02:	/* Polarity inversion */

        return s->polarity;

    case 0x03:	/* Configuration */

        return s->direction;

    case 0x04:	/* Timeout */

        return s->status;

        break;

    case 0xff:	/* Reserved */

        return 0xff;

    default:

#ifdef VERBOSE

        printf("%s: unknown register %02x\n", __FUNCTION__, s->command);

#endif

        break;

    }

    return 0xff;

}

static int max7310_tx(i2c_slave *i2c, uint8_t data)

{

    struct max7310_s *s = (struct max7310_s *) i2c;

    uint8_t diff;

    int line;

    if (s->len ++ > 1) {

#ifdef VERBOSE

        printf("%s: message too long (%i bytes)\n", __FUNCTION__, s->len);

#endif

        return 1;

    }

    if (s->i2c_command_byte) {

        s->command = data;

        s->i2c_command_byte = 0;

        return 0;

    }

    switch (s->command) {

    case 0x01:	/* Output port */

        for (diff = (data ^ s->level) & ~s->direction; diff;

                        diff &= ~(1 << line)) {

            line = ffs(diff) - 1;

            if (s->handler[line])

                qemu_set_irq(s->handler[line], (data >> line) & 1);

        }

        s->level = (s->level & s->direction) | (data & ~s->direction);

        break;

    case 0x02:	/* Polarity inversion */

        s->polarity = data;

        break;

    case 0x03:	/* Configuration */

        s->level &= ~(s->direction ^ data);

        s->direction = data;

        break;

    case 0x04:	/* Timeout */

        s->status = data;

        break;

    case 0x00:	/* Input port - ignore writes */

	break;

    default:

#ifdef VERBOSE

        printf("%s: unknown register %02x\n", __FUNCTION__, s->command);

#endif

        return 1;

    }

    return 0;

}

static void max7310_event(i2c_slave *i2c, enum i2c_event event)

{

    struct max7310_s *s = (struct max7310_s *) i2c;

    s->len = 0;

    switch (event) {

    case I2C_START_SEND:

        s->i2c_command_byte = 1;

        break;

    case I2C_FINISH:

#ifdef VERBOSE

        if (s->len == 1)

            printf("%s: message too short (%i bytes)\n", __FUNCTION__, s->len);

#endif

        break;

    default:

        break;

    }

}

static void max7310_save(QEMUFile *f, void *opaque)

{

    struct max7310_s *s = (struct max7310_s *) opaque;

    qemu_put_be32(f, s->i2c_command_byte);

    qemu_put_be32(f, s->len);

    qemu_put_8s(f, &s->level);

    qemu_put_8s(f, &s->direction);

    qemu_put_8s(f, &s->polarity);

    qemu_put_8s(f, &s->status);

    qemu_put_8s(f, &s->command);

    i2c_slave_save(f, &s->i2c);

}

static int max7310_load(QEMUFile *f, void *opaque, int version_id)

{

    struct max7310_s *s = (struct max7310_s *) opaque;

    s->i2c_command_byte = qemu_get_be32(f);

    s->len = qemu_get_be32(f);

    qemu_get_8s(f, &s->level);

    qemu_get_8s(f, &s->direction);

    qemu_get_8s(f, &s->polarity);

    qemu_get_8s(f, &s->status);

    qemu_get_8s(f, &s->command);

    i2c_slave_load(f, &s->i2c);

    return 0;

}

static void max7310_gpio_set(void *opaque, int line, int level)

{

    struct max7310_s *s = (struct max7310_s *) opaque;

    if (line >= ARRAY_SIZE(s->handler) || line  < 0)

        hw_error("bad GPIO line");

    if (level)

        s->level |= s->direction & (1 << line);

    else

        s->level &= ~(s->direction & (1 << line));

}

/* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),

 * but also accepts sequences that are not SMBus so return an I2C device.  */

struct i2c_slave *max7310_init(i2c_bus *bus)

{

    struct max7310_s *s = (struct max7310_s *)

            i2c_slave_init(bus, 0, sizeof(struct max7310_s));

    s->i2c.event = max7310_event;

    s->i2c.recv = max7310_rx;

    s->i2c.send = max7310_tx;

    s->gpio_in = qemu_allocate_irqs(max7310_gpio_set, s,

                    ARRAY_SIZE(s->handler));

    max7310_reset(&s->i2c);

    register_savevm("max7310", -1, 0, max7310_save, max7310_load, s);

    return &s->i2c;

}

qemu_irq *max7310_gpio_in_get(i2c_slave *i2c)

{

    struct max7310_s *s = (struct max7310_s *) i2c;

    return s->gpio_in;

}

void max7310_gpio_out_set(i2c_slave *i2c, int line, qemu_irq handler)

{

    struct max7310_s *s = (struct max7310_s *) i2c;

    if (line >= ARRAY_SIZE(s->handler) || line  < 0)

        hw_error("bad GPIO line");

    s->handler[line] = handler;

}