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/hw.h"
  12 #include "hw/i2c/i2c.h"
  13 #include "hw/hw.h"
  14 #include "hw/irq.h"
  15 #include "migration/vmstate.h"
  16 #include "qemu/module.h"
  17
  18 #define TYPE_MAX7310 "max7310"
  19 #define MAX7310(obj) OBJECT_CHECK(MAX7310State, (obj), TYPE_MAX7310)
  20
  21 typedef struct MAX7310State {
  22     I2CSlave parent_obj;
  23
  24     int i2c_command_byte;
  25     int len;
  26
  27     uint8_t level;
  28     uint8_t direction;
  29     uint8_t polarity;
  30     uint8_t status;
  31     uint8_t command;
  32     qemu_irq handler[8];
  33     qemu_irq *gpio_in;
  34 } MAX7310State;
  35
  36 static void max7310_reset(DeviceState *dev)
  37 {
  38     MAX7310State *s = MAX7310(dev);
  39
  40     s->level &= s->direction;
  41     s->direction = 0xff;
  42     s->polarity = 0xf0;
  43     s->status = 0x01;
  44     s->command = 0x00;
  45 }
  46
  47 static uint8_t max7310_rx(I2CSlave *i2c)
  48 {
  49     MAX7310State *s = MAX7310(i2c);
  50
  51     switch (s->command) {
  52     case 0x00:  /* Input port */
  53         return s->level ^ s->polarity;
  54         break;
  55
  56     case 0x01:  /* Output port */
  57         return s->level & ~s->direction;
  58         break;
  59
  60     case 0x02:  /* Polarity inversion */
  61         return s->polarity;
  62
  63     case 0x03:  /* Configuration */
  64         return s->direction;
  65
  66     case 0x04:  /* Timeout */
  67         return s->status;
  68         break;
  69
  70     case 0xff:  /* Reserved */
  71         return 0xff;
  72
  73     default:
  74 #ifdef VERBOSE
  75         printf("%s: unknown register %02x\n", __func__, s->command);
  76 #endif
  77         break;
  78     }
  79     return 0xff;
  80 }
  81
  82 static int max7310_tx(I2CSlave *i2c, uint8_t data)
  83 {
  84     MAX7310State *s = MAX7310(i2c);
  85     uint8_t diff;
  86     int line;
  87
  88     if (s->len ++ > 1) {
  89 #ifdef VERBOSE
  90         printf("%s: message too long (%i bytes)\n", __func__, s->len);
  91 #endif
  92         return 1;
  93     }
  94
  95     if (s->i2c_command_byte) {
  96         s->command = data;
  97         s->i2c_command_byte = 0;
  98         return 0;
  99     }
 100
 101     switch (s->command) {
 102     case 0x01:  /* Output port */
 103         for (diff = (data ^ s->level) & ~s->direction; diff;
 104                         diff &= ~(1 << line)) {
 105             line = ctz32(diff);
 106             if (s->handler[line])
 107                 qemu_set_irq(s->handler[line], (data >> line) & 1);
 108         }
 109         s->level = (s->level & s->direction) | (data & ~s->direction);
 110         break;
 111
 112     case 0x02:  /* Polarity inversion */
 113         s->polarity = data;
 114         break;
 115
 116     case 0x03:  /* Configuration */
 117         s->level &= ~(s->direction ^ data);
 118         s->direction = data;
 119         break;
 120
 121     case 0x04:  /* Timeout */
 122         s->status = data;
 123         break;
 124
 125     case 0x00:  /* Input port - ignore writes */
 126         break;
 127     default:
 128 #ifdef VERBOSE
 129         printf("%s: unknown register %02x\n", __func__, s->command);
 130 #endif
 131         return 1;
 132     }
 133
 134     return 0;
 135 }
 136
 137 static int max7310_event(I2CSlave *i2c, enum i2c_event event)
 138 {
 139     MAX7310State *s = MAX7310(i2c);
 140     s->len = 0;
 141
 142     switch (event) {
 143     case I2C_START_SEND:
 144         s->i2c_command_byte = 1;
 145         break;
 146     case I2C_FINISH:
 147 #ifdef VERBOSE
 148         if (s->len == 1)
 149             printf("%s: message too short (%i bytes)\n", __func__, s->len);
 150 #endif
 151         break;
 152     default:
 153         break;
 154     }
 155
 156     return 0;
 157 }
 158
 159 static const VMStateDescription vmstate_max7310 = {
 160     .name = "max7310",
 161     .version_id = 0,
 162     .minimum_version_id = 0,
 163     .fields = (VMStateField[]) {
 164         VMSTATE_INT32(i2c_command_byte, MAX7310State),
 165         VMSTATE_INT32(len, MAX7310State),
 166         VMSTATE_UINT8(level, MAX7310State),
 167         VMSTATE_UINT8(direction, MAX7310State),
 168         VMSTATE_UINT8(polarity, MAX7310State),
 169         VMSTATE_UINT8(status, MAX7310State),
 170         VMSTATE_UINT8(command, MAX7310State),
 171         VMSTATE_I2C_SLAVE(parent_obj, MAX7310State),
 172         VMSTATE_END_OF_LIST()
 173     }
 174 };
 175
 176 static void max7310_gpio_set(void *opaque, int line, int level)
 177 {
 178     MAX7310State *s = (MAX7310State *) opaque;
 179     if (line >= ARRAY_SIZE(s->handler) || line  < 0)
 180         hw_error("bad GPIO line");
 181
 182     if (level)
 183         s->level |= s->direction & (1 << line);
 184     else
 185         s->level &= ~(s->direction & (1 << line));
 186 }
 187
 188 /* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 189  * but also accepts sequences that are not SMBus so return an I2C device.  */
 190 static void max7310_realize(DeviceState *dev, Error **errp)
 191 {
 192     I2CSlave *i2c = I2C_SLAVE(dev);
 193     MAX7310State *s = MAX7310(dev);
 194
 195     qdev_init_gpio_in(&i2c->qdev, max7310_gpio_set, 8);
 196     qdev_init_gpio_out(&i2c->qdev, s->handler, 8);
 197 }
 198
 199 static void max7310_class_init(ObjectClass *klass, void *data)
 200 {
 201     DeviceClass *dc = DEVICE_CLASS(klass);
 202     I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
 203
 204     dc->realize = max7310_realize;
 205     k->event = max7310_event;
 206     k->recv = max7310_rx;
 207     k->send = max7310_tx;
 208     dc->reset = max7310_reset;
 209     dc->vmsd = &vmstate_max7310;
 210 }
 211
 212 static const TypeInfo max7310_info = {
 213     .name          = TYPE_MAX7310,
 214     .parent        = TYPE_I2C_SLAVE,
 215     .instance_size = sizeof(MAX7310State),
 216     .class_init    = max7310_class_init,
 217 };
 218
 219 static void max7310_register_types(void)
 220 {
 221     type_register_static(&max7310_info);
 222 }
 223
 224 type_init(max7310_register_types)