qemu/hw/gpio/max7310.c
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   1/*
   2 * MAX7310 8-port GPIO expansion chip.
   3 *
   4 * Copyright (c) 2006 Openedhand Ltd.
   5 * Written by Andrzej Zaborowski <balrog@zabor.org>
   6 *
   7 * This file is licensed under GNU GPL.
   8 */
   9
  10#include "qemu/osdep.h"
  11#include "hw/i2c/i2c.h"
  12#include "qemu/module.h"
  13
  14#define TYPE_MAX7310 "max7310"
  15#define MAX7310(obj) OBJECT_CHECK(MAX7310State, (obj), TYPE_MAX7310)
  16
  17typedef struct MAX7310State {
  18    I2CSlave parent_obj;
  19
  20    int i2c_command_byte;
  21    int len;
  22
  23    uint8_t level;
  24    uint8_t direction;
  25    uint8_t polarity;
  26    uint8_t status;
  27    uint8_t command;
  28    qemu_irq handler[8];
  29    qemu_irq *gpio_in;
  30} MAX7310State;
  31
  32static void max7310_reset(DeviceState *dev)
  33{
  34    MAX7310State *s = MAX7310(dev);
  35
  36    s->level &= s->direction;
  37    s->direction = 0xff;
  38    s->polarity = 0xf0;
  39    s->status = 0x01;
  40    s->command = 0x00;
  41}
  42
  43static uint8_t max7310_rx(I2CSlave *i2c)
  44{
  45    MAX7310State *s = MAX7310(i2c);
  46
  47    switch (s->command) {
  48    case 0x00:  /* Input port */
  49        return s->level ^ s->polarity;
  50        break;
  51
  52    case 0x01:  /* Output port */
  53        return s->level & ~s->direction;
  54        break;
  55
  56    case 0x02:  /* Polarity inversion */
  57        return s->polarity;
  58
  59    case 0x03:  /* Configuration */
  60        return s->direction;
  61
  62    case 0x04:  /* Timeout */
  63        return s->status;
  64        break;
  65
  66    case 0xff:  /* Reserved */
  67        return 0xff;
  68
  69    default:
  70#ifdef VERBOSE
  71        printf("%s: unknown register %02x\n", __func__, s->command);
  72#endif
  73        break;
  74    }
  75    return 0xff;
  76}
  77
  78static int max7310_tx(I2CSlave *i2c, uint8_t data)
  79{
  80    MAX7310State *s = MAX7310(i2c);
  81    uint8_t diff;
  82    int line;
  83
  84    if (s->len ++ > 1) {
  85#ifdef VERBOSE
  86        printf("%s: message too long (%i bytes)\n", __func__, s->len);
  87#endif
  88        return 1;
  89    }
  90
  91    if (s->i2c_command_byte) {
  92        s->command = data;
  93        s->i2c_command_byte = 0;
  94        return 0;
  95    }
  96
  97    switch (s->command) {
  98    case 0x01:  /* Output port */
  99        for (diff = (data ^ s->level) & ~s->direction; diff;
 100                        diff &= ~(1 << line)) {
 101            line = ctz32(diff);
 102            if (s->handler[line])
 103                qemu_set_irq(s->handler[line], (data >> line) & 1);
 104        }
 105        s->level = (s->level & s->direction) | (data & ~s->direction);
 106        break;
 107
 108    case 0x02:  /* Polarity inversion */
 109        s->polarity = data;
 110        break;
 111
 112    case 0x03:  /* Configuration */
 113        s->level &= ~(s->direction ^ data);
 114        s->direction = data;
 115        break;
 116
 117    case 0x04:  /* Timeout */
 118        s->status = data;
 119        break;
 120
 121    case 0x00:  /* Input port - ignore writes */
 122        break;
 123    default:
 124#ifdef VERBOSE
 125        printf("%s: unknown register %02x\n", __func__, s->command);
 126#endif
 127        return 1;
 128    }
 129
 130    return 0;
 131}
 132
 133static int max7310_event(I2CSlave *i2c, enum i2c_event event)
 134{
 135    MAX7310State *s = MAX7310(i2c);
 136    s->len = 0;
 137
 138    switch (event) {
 139    case I2C_START_SEND:
 140        s->i2c_command_byte = 1;
 141        break;
 142    case I2C_FINISH:
 143#ifdef VERBOSE
 144        if (s->len == 1)
 145            printf("%s: message too short (%i bytes)\n", __func__, s->len);
 146#endif
 147        break;
 148    default:
 149        break;
 150    }
 151
 152    return 0;
 153}
 154
 155static const VMStateDescription vmstate_max7310 = {
 156    .name = "max7310",
 157    .version_id = 0,
 158    .minimum_version_id = 0,
 159    .fields = (VMStateField[]) {
 160        VMSTATE_INT32(i2c_command_byte, MAX7310State),
 161        VMSTATE_INT32(len, MAX7310State),
 162        VMSTATE_UINT8(level, MAX7310State),
 163        VMSTATE_UINT8(direction, MAX7310State),
 164        VMSTATE_UINT8(polarity, MAX7310State),
 165        VMSTATE_UINT8(status, MAX7310State),
 166        VMSTATE_UINT8(command, MAX7310State),
 167        VMSTATE_I2C_SLAVE(parent_obj, MAX7310State),
 168        VMSTATE_END_OF_LIST()
 169    }
 170};
 171
 172static void max7310_gpio_set(void *opaque, int line, int level)
 173{
 174    MAX7310State *s = (MAX7310State *) opaque;
 175    if (line >= ARRAY_SIZE(s->handler) || line  < 0)
 176        hw_error("bad GPIO line");
 177
 178    if (level)
 179        s->level |= s->direction & (1 << line);
 180    else
 181        s->level &= ~(s->direction & (1 << line));
 182}
 183
 184/* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 185 * but also accepts sequences that are not SMBus so return an I2C device.  */
 186static void max7310_realize(DeviceState *dev, Error **errp)
 187{
 188    I2CSlave *i2c = I2C_SLAVE(dev);
 189    MAX7310State *s = MAX7310(dev);
 190
 191    qdev_init_gpio_in(&i2c->qdev, max7310_gpio_set, 8);
 192    qdev_init_gpio_out(&i2c->qdev, s->handler, 8);
 193}
 194
 195static void max7310_class_init(ObjectClass *klass, void *data)
 196{
 197    DeviceClass *dc = DEVICE_CLASS(klass);
 198    I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
 199
 200    dc->realize = max7310_realize;
 201    k->event = max7310_event;
 202    k->recv = max7310_rx;
 203    k->send = max7310_tx;
 204    dc->reset = max7310_reset;
 205    dc->vmsd = &vmstate_max7310;
 206}
 207
 208static const TypeInfo max7310_info = {
 209    .name          = TYPE_MAX7310,
 210    .parent        = TYPE_I2C_SLAVE,
 211    .instance_size = sizeof(MAX7310State),
 212    .class_init    = max7310_class_init,
 213};
 214
 215static void max7310_register_types(void)
 216{
 217    type_register_static(&max7310_info);
 218}
 219
 220type_init(max7310_register_types)
 221