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 "migration/vmstate.h"
  14 #include "qemu/log.h"
  15 #include "qemu/module.h"
  16 #include "qom/object.h"
  17
  18 #define TYPE_MAX7310 "max7310"
  19 OBJECT_DECLARE_SIMPLE_TYPE(MAX7310State, MAX7310)
  20
  21 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 };
  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
  55     case 0x01:  /* Output port */
  56         return s->level & ~s->direction;
  57
  58     case 0x02:  /* Polarity inversion */
  59         return s->polarity;
  60
  61     case 0x03:  /* Configuration */
  62         return s->direction;
  63
  64     case 0x04:  /* Timeout */
  65         return s->status;
  66
  67     case 0xff:  /* Reserved */
  68         return 0xff;
  69
  70     default:
  71         qemu_log_mask(LOG_UNIMP, "%s: Unsupported register 0x02%" PRIx8 "\n",
  72                       __func__, s->command);
  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         qemu_log_mask(LOG_UNIMP, "%s: Unsupported register 0x02%" PRIx8 "\n",
 125                       __func__, s->command);
 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", __func__, 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 = (const 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     assert(line >= 0 && line < ARRAY_SIZE(s->handler));
 175
 176     if (level)
 177         s->level |= s->direction & (1 << line);
 178     else
 179         s->level &= ~(s->direction & (1 << line));
 180 }
 181
 182 /* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 183  * but also accepts sequences that are not SMBus so return an I2C device.  */
 184 static void max7310_realize(DeviceState *dev, Error **errp)
 185 {
 186     MAX7310State *s = MAX7310(dev);
 187
 188     qdev_init_gpio_in(dev, max7310_gpio_set, ARRAY_SIZE(s->handler));
 189     qdev_init_gpio_out(dev, s->handler, ARRAY_SIZE(s->handler));
 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     dc->realize = max7310_realize;
 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)