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