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
  16 typedef 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
  31 static 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
  42 static 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", __FUNCTION__, s->command);
  71 #endif
  72         break;
  73     }
  74     return 0xff;
  75 }
  76
  77 static 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", __FUNCTION__, 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", __FUNCTION__, s->command);
 125 #endif
 126         return 1;
 127     }
 128
 129     return 0;
 130 }
 131
 132 static 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", __FUNCTION__, s->len);
 145 #endif
 146         break;
 147     default:
 148         break;
 149     }
 150
 151     return 0;
 152 }
 153
 154 static 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
 171 static 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.  */
 185 static int max7310_init(I2CSlave *i2c)
 186 {
 187     MAX7310State *s = MAX7310(i2c);
 188
 189     qdev_init_gpio_in(&i2c->qdev, max7310_gpio_set, 8);
 190     qdev_init_gpio_out(&i2c->qdev, s->handler, 8);
 191
 192     return 0;
 193 }
 194
 195 static void max7310_class_init(ObjectClass *klass, void *data)
 196 {
 197     DeviceClass *dc = DEVICE_CLASS(klass);
 198     I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
 199
 200     k->init = max7310_init;
 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
 208 static 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
 215 static void max7310_register_types(void)
 216 {
 217     type_register_static(&max7310_info);
 218 }
 219
 220 type_init(max7310_register_types)