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