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