LXR qemu/hw/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 "i2c.h"
  11
  12typedef struct {
  13    i2c_slave i2c;
  14    int i2c_command_byte;
  15    int len;
  16
  17    uint8_t level;
  18    uint8_t direction;
  19    uint8_t polarity;
  20    uint8_t status;
  21    uint8_t command;
  22    qemu_irq handler[8];
  23    qemu_irq *gpio_in;
  24} MAX7310State;
  25
  26void max7310_reset(i2c_slave *i2c)
  27{
  28    MAX7310State *s = (MAX7310State *) i2c;
  29    s->level &= s->direction;
  30    s->direction = 0xff;
  31    s->polarity = 0xf0;
  32    s->status = 0x01;
  33    s->command = 0x00;
  34}
  35
  36static int max7310_rx(i2c_slave *i2c)
  37{
  38    MAX7310State *s = (MAX7310State *) i2c;
  39
  40    switch (s->command) {
  41    case 0x00:  /* Input port */
  42        return s->level ^ s->polarity;
  43        break;
  44
  45    case 0x01:  /* Output port */
  46        return s->level & ~s->direction;
  47        break;
  48
  49    case 0x02:  /* Polarity inversion */
  50        return s->polarity;
  51
  52    case 0x03:  /* Configuration */
  53        return s->direction;
  54
  55    case 0x04:  /* Timeout */
  56        return s->status;
  57        break;
  58
  59    case 0xff:  /* Reserved */
  60        return 0xff;
  61
  62    default:
  63#ifdef VERBOSE
  64        printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
  65#endif
  66        break;
  67    }
  68    return 0xff;
  69}
  70
  71static int max7310_tx(i2c_slave *i2c, uint8_t data)
  72{
  73    MAX7310State *s = (MAX7310State *) i2c;
  74    uint8_t diff;
  75    int line;
  76
  77    if (s->len ++ > 1) {
  78#ifdef VERBOSE
  79        printf("%s: message too long (%i bytes)\n", __FUNCTION__, s->len);
  80#endif
  81        return 1;
  82    }
  83
  84    if (s->i2c_command_byte) {
  85        s->command = data;
  86        s->i2c_command_byte = 0;
  87        return 0;
  88    }
  89
  90    switch (s->command) {
  91    case 0x01:  /* Output port */
  92        for (diff = (data ^ s->level) & ~s->direction; diff;
  93                        diff &= ~(1 << line)) {
  94            line = ffs(diff) - 1;
  95            if (s->handler[line])
  96                qemu_set_irq(s->handler[line], (data >> line) & 1);
  97        }
  98        s->level = (s->level & s->direction) | (data & ~s->direction);
  99        break;
 100
 101    case 0x02:  /* Polarity inversion */
 102        s->polarity = data;
 103        break;
 104
 105    case 0x03:  /* Configuration */
 106        s->level &= ~(s->direction ^ data);
 107        s->direction = data;
 108        break;
 109
 110    case 0x04:  /* Timeout */
 111        s->status = data;
 112        break;
 113
 114    case 0x00:  /* Input port - ignore writes */
 115        break;
 116    default:
 117#ifdef VERBOSE
 118        printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
 119#endif
 120        return 1;
 121    }
 122
 123    return 0;
 124}
 125
 126static void max7310_event(i2c_slave *i2c, enum i2c_event event)
 127{
 128    MAX7310State *s = (MAX7310State *) i2c;
 129    s->len = 0;
 130
 131    switch (event) {
 132    case I2C_START_SEND:
 133        s->i2c_command_byte = 1;
 134        break;
 135    case I2C_FINISH:
 136#ifdef VERBOSE
 137        if (s->len == 1)
 138            printf("%s: message too short (%i bytes)\n", __FUNCTION__, s->len);
 139#endif
 140        break;
 141    default:
 142        break;
 143    }
 144}
 145
 146static const VMStateDescription vmstate_max7310 = {
 147    .name = "max7310",
 148    .version_id = 0,
 149    .minimum_version_id = 0,
 150    .minimum_version_id_old = 0,
 151    .fields      = (VMStateField []) {
 152        VMSTATE_INT32(i2c_command_byte, MAX7310State),
 153        VMSTATE_INT32(len, MAX7310State),
 154        VMSTATE_UINT8(level, MAX7310State),
 155        VMSTATE_UINT8(direction, MAX7310State),
 156        VMSTATE_UINT8(polarity, MAX7310State),
 157        VMSTATE_UINT8(status, MAX7310State),
 158        VMSTATE_UINT8(command, MAX7310State),
 159        VMSTATE_I2C_SLAVE(i2c, MAX7310State),
 160        VMSTATE_END_OF_LIST()
 161    }
 162};
 163
 164static void max7310_gpio_set(void *opaque, int line, int level)
 165{
 166    MAX7310State *s = (MAX7310State *) opaque;
 167    if (line >= ARRAY_SIZE(s->handler) || line  < 0)
 168        hw_error("bad GPIO line");
 169
 170    if (level)
 171        s->level |= s->direction & (1 << line);
 172    else
 173        s->level &= ~(s->direction & (1 << line));
 174}
 175
 176/* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 177 * but also accepts sequences that are not SMBus so return an I2C device.  */
 178static int max7310_init(i2c_slave *i2c)
 179{
 180    MAX7310State *s = FROM_I2C_SLAVE(MAX7310State, i2c);
 181
 182    s->gpio_in = qemu_allocate_irqs(max7310_gpio_set, s,
 183                    ARRAY_SIZE(s->handler));
 184
 185    max7310_reset(&s->i2c);
 186
 187    return 0;
 188}
 189
 190qemu_irq *max7310_gpio_in_get(i2c_slave *i2c)
 191{
 192    MAX7310State *s = (MAX7310State *) i2c;
 193    return s->gpio_in;
 194}
 195
 196void max7310_gpio_out_set(i2c_slave *i2c, int line, qemu_irq handler)
 197{
 198    MAX7310State *s = (MAX7310State *) i2c;
 199    if (line >= ARRAY_SIZE(s->handler) || line  < 0)
 200        hw_error("bad GPIO line");
 201
 202    s->handler[line] = handler;
 203}
 204
 205static I2CSlaveInfo max7310_info = {
 206    .qdev.name = "max7310",
 207    .qdev.size = sizeof(MAX7310State),
 208    .qdev.vmsd = &vmstate_max7310,
 209    .init = max7310_init,
 210    .event = max7310_event,
 211    .recv = max7310_rx,
 212    .send = max7310_tx
 213};
 214
 215static void max7310_register_devices(void)
 216{
 217    i2c_register_slave(&max7310_info);
 218}
 219
 220device_init(max7310_register_devices)
 221