LXR qemu/hw/gpio/max7310.c

   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 "hw/i2c/i2c.h"
  11
  12#define TYPE_MAX7310 "max7310"
  13#define MAX7310(obj) OBJECT_CHECK(MAX7310State, (obj), TYPE_MAX7310)
  14
  15typedef struct MAX7310State {
  16    I2CSlave parent_obj;
  17
  18    int i2c_command_byte;
  19    int len;
  20
  21    uint8_t level;
  22    uint8_t direction;
  23    uint8_t polarity;
  24    uint8_t status;
  25    uint8_t command;
  26    qemu_irq handler[8];
  27    qemu_irq *gpio_in;
  28} MAX7310State;
  29
  30static void max7310_reset(DeviceState *dev)
  31{
  32    MAX7310State *s = MAX7310(dev);
  33
  34    s->level &= s->direction;
  35    s->direction = 0xff;
  36    s->polarity = 0xf0;
  37    s->status = 0x01;
  38    s->command = 0x00;
  39}
  40
  41static int max7310_rx(I2CSlave *i2c)
  42{
  43    MAX7310State *s = MAX7310(i2c);
  44
  45    switch (s->command) {
  46    case 0x00:  /* Input port */
  47        return s->level ^ s->polarity;
  48        break;
  49
  50    case 0x01:  /* Output port */
  51        return s->level & ~s->direction;
  52        break;
  53
  54    case 0x02:  /* Polarity inversion */
  55        return s->polarity;
  56
  57    case 0x03:  /* Configuration */
  58        return s->direction;
  59
  60    case 0x04:  /* Timeout */
  61        return s->status;
  62        break;
  63
  64    case 0xff:  /* Reserved */
  65        return 0xff;
  66
  67    default:
  68#ifdef VERBOSE
  69        printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
  70#endif
  71        break;
  72    }
  73    return 0xff;
  74}
  75
  76static int max7310_tx(I2CSlave *i2c, uint8_t data)
  77{
  78    MAX7310State *s = MAX7310(i2c);
  79    uint8_t diff;
  80    int line;
  81
  82    if (s->len ++ > 1) {
  83#ifdef VERBOSE
  84        printf("%s: message too long (%i bytes)\n", __FUNCTION__, s->len);
  85#endif
  86        return 1;
  87    }
  88
  89    if (s->i2c_command_byte) {
  90        s->command = data;
  91        s->i2c_command_byte = 0;
  92        return 0;
  93    }
  94
  95    switch (s->command) {
  96    case 0x01:  /* Output port */
  97        for (diff = (data ^ s->level) & ~s->direction; diff;
  98                        diff &= ~(1 << line)) {
  99            line = ctz32(diff);
 100            if (s->handler[line])
 101                qemu_set_irq(s->handler[line], (data >> line) & 1);
 102        }
 103        s->level = (s->level & s->direction) | (data & ~s->direction);
 104        break;
 105
 106    case 0x02:  /* Polarity inversion */
 107        s->polarity = data;
 108        break;
 109
 110    case 0x03:  /* Configuration */
 111        s->level &= ~(s->direction ^ data);
 112        s->direction = data;
 113        break;
 114
 115    case 0x04:  /* Timeout */
 116        s->status = data;
 117        break;
 118
 119    case 0x00:  /* Input port - ignore writes */
 120        break;
 121    default:
 122#ifdef VERBOSE
 123        printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
 124#endif
 125        return 1;
 126    }
 127
 128    return 0;
 129}
 130
 131static void max7310_event(I2CSlave *i2c, enum i2c_event event)
 132{
 133    MAX7310State *s = MAX7310(i2c);
 134    s->len = 0;
 135
 136    switch (event) {
 137    case I2C_START_SEND:
 138        s->i2c_command_byte = 1;
 139        break;
 140    case I2C_FINISH:
 141#ifdef VERBOSE
 142        if (s->len == 1)
 143            printf("%s: message too short (%i bytes)\n", __FUNCTION__, s->len);
 144#endif
 145        break;
 146    default:
 147        break;
 148    }
 149}
 150
 151static const VMStateDescription vmstate_max7310 = {
 152    .name = "max7310",
 153    .version_id = 0,
 154    .minimum_version_id = 0,
 155    .fields = (VMStateField[]) {
 156        VMSTATE_INT32(i2c_command_byte, MAX7310State),
 157        VMSTATE_INT32(len, MAX7310State),
 158        VMSTATE_UINT8(level, MAX7310State),
 159        VMSTATE_UINT8(direction, MAX7310State),
 160        VMSTATE_UINT8(polarity, MAX7310State),
 161        VMSTATE_UINT8(status, MAX7310State),
 162        VMSTATE_UINT8(command, MAX7310State),
 163        VMSTATE_I2C_SLAVE(parent_obj, MAX7310State),
 164        VMSTATE_END_OF_LIST()
 165    }
 166};
 167
 168static void max7310_gpio_set(void *opaque, int line, int level)
 169{
 170    MAX7310State *s = (MAX7310State *) opaque;
 171    if (line >= ARRAY_SIZE(s->handler) || line  < 0)
 172        hw_error("bad GPIO line");
 173
 174    if (level)
 175        s->level |= s->direction & (1 << line);
 176    else
 177        s->level &= ~(s->direction & (1 << line));
 178}
 179
 180/* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 181 * but also accepts sequences that are not SMBus so return an I2C device.  */
 182static int max7310_init(I2CSlave *i2c)
 183{
 184    MAX7310State *s = MAX7310(i2c);
 185
 186    qdev_init_gpio_in(&i2c->qdev, max7310_gpio_set, 8);
 187    qdev_init_gpio_out(&i2c->qdev, s->handler, 8);
 188
 189    return 0;
 190}
 191
 192static void max7310_class_init(ObjectClass *klass, void *data)
 193{
 194    DeviceClass *dc = DEVICE_CLASS(klass);
 195    I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
 196
 197    k->init = max7310_init;
 198    k->event = max7310_event;
 199    k->recv = max7310_rx;
 200    k->send = max7310_tx;
 201    dc->reset = max7310_reset;
 202    dc->vmsd = &vmstate_max7310;
 203}
 204
 205static const TypeInfo max7310_info = {
 206    .name          = TYPE_MAX7310,
 207    .parent        = TYPE_I2C_SLAVE,
 208    .instance_size = sizeof(MAX7310State),
 209    .class_init    = max7310_class_init,
 210};
 211
 212static void max7310_register_types(void)
 213{
 214    type_register_static(&max7310_info);
 215}
 216
 217type_init(max7310_register_types)
 218