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
  15 typedef 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
  30 static 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
  41 static 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
  76 static 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
 131 static 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
 151 static 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
 168 static 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.  */
 182 static 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
 192 static 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
 205 static 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
 212 static void max7310_register_types(void)
 213 {
 214     type_register_static(&max7310_info);
 215 }
 216
 217 type_init(max7310_register_types)