hw/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 "i2c.h"
  11
  12 typedef struct {
  13     i2c_slave i2c;
  14     int i2c_command_byte;
  15     int len;
  16
  17     uint8_t level;
  18     uint8_t direction;
  19     uint8_t polarity;
  20     uint8_t status;
  21     uint8_t command;
  22     qemu_irq handler[8];
  23     qemu_irq *gpio_in;
  24 } MAX7310State;
  25
  26 static void max7310_reset(DeviceState *dev)
  27 {
  28     MAX7310State *s = FROM_I2C_SLAVE(MAX7310State, I2C_SLAVE_FROM_QDEV(dev));
  29     s->level &= s->direction;
  30     s->direction = 0xff;
  31     s->polarity = 0xf0;
  32     s->status = 0x01;
  33     s->command = 0x00;
  34 }
  35
  36 static int max7310_rx(i2c_slave *i2c)
  37 {
  38     MAX7310State *s = (MAX7310State *) i2c;
  39
  40     switch (s->command) {
  41     case 0x00:  /* Input port */
  42         return s->level ^ s->polarity;
  43         break;
  44
  45     case 0x01:  /* Output port */
  46         return s->level & ~s->direction;
  47         break;
  48
  49     case 0x02:  /* Polarity inversion */
  50         return s->polarity;
  51
  52     case 0x03:  /* Configuration */
  53         return s->direction;
  54
  55     case 0x04:  /* Timeout */
  56         return s->status;
  57         break;
  58
  59     case 0xff:  /* Reserved */
  60         return 0xff;
  61
  62     default:
  63 #ifdef VERBOSE
  64         printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
  65 #endif
  66         break;
  67     }
  68     return 0xff;
  69 }
  70
  71 static int max7310_tx(i2c_slave *i2c, uint8_t data)
  72 {
  73     MAX7310State *s = (MAX7310State *) i2c;
  74     uint8_t diff;
  75     int line;
  76
  77     if (s->len ++ > 1) {
  78 #ifdef VERBOSE
  79         printf("%s: message too long (%i bytes)\n", __FUNCTION__, s->len);
  80 #endif
  81         return 1;
  82     }
  83
  84     if (s->i2c_command_byte) {
  85         s->command = data;
  86         s->i2c_command_byte = 0;
  87         return 0;
  88     }
  89
  90     switch (s->command) {
  91     case 0x01:  /* Output port */
  92         for (diff = (data ^ s->level) & ~s->direction; diff;
  93                         diff &= ~(1 << line)) {
  94             line = ffs(diff) - 1;
  95             if (s->handler[line])
  96                 qemu_set_irq(s->handler[line], (data >> line) & 1);
  97         }
  98         s->level = (s->level & s->direction) | (data & ~s->direction);
  99         break;
 100
 101     case 0x02:  /* Polarity inversion */
 102         s->polarity = data;
 103         break;
 104
 105     case 0x03:  /* Configuration */
 106         s->level &= ~(s->direction ^ data);
 107         s->direction = data;
 108         break;
 109
 110     case 0x04:  /* Timeout */
 111         s->status = data;
 112         break;
 113
 114     case 0x00:  /* Input port - ignore writes */
 115         break;
 116     default:
 117 #ifdef VERBOSE
 118         printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
 119 #endif
 120         return 1;
 121     }
 122
 123     return 0;
 124 }
 125
 126 static void max7310_event(i2c_slave *i2c, enum i2c_event event)
 127 {
 128     MAX7310State *s = (MAX7310State *) i2c;
 129     s->len = 0;
 130
 131     switch (event) {
 132     case I2C_START_SEND:
 133         s->i2c_command_byte = 1;
 134         break;
 135     case I2C_FINISH:
 136 #ifdef VERBOSE
 137         if (s->len == 1)
 138             printf("%s: message too short (%i bytes)\n", __FUNCTION__, s->len);
 139 #endif
 140         break;
 141     default:
 142         break;
 143     }
 144 }
 145
 146 static const VMStateDescription vmstate_max7310 = {
 147     .name = "max7310",
 148     .version_id = 0,
 149     .minimum_version_id = 0,
 150     .minimum_version_id_old = 0,
 151     .fields      = (VMStateField []) {
 152         VMSTATE_INT32(i2c_command_byte, MAX7310State),
 153         VMSTATE_INT32(len, MAX7310State),
 154         VMSTATE_UINT8(level, MAX7310State),
 155         VMSTATE_UINT8(direction, MAX7310State),
 156         VMSTATE_UINT8(polarity, MAX7310State),
 157         VMSTATE_UINT8(status, MAX7310State),
 158         VMSTATE_UINT8(command, MAX7310State),
 159         VMSTATE_I2C_SLAVE(i2c, MAX7310State),
 160         VMSTATE_END_OF_LIST()
 161     }
 162 };
 163
 164 static void max7310_gpio_set(void *opaque, int line, int level)
 165 {
 166     MAX7310State *s = (MAX7310State *) opaque;
 167     if (line >= ARRAY_SIZE(s->handler) || line  < 0)
 168         hw_error("bad GPIO line");
 169
 170     if (level)
 171         s->level |= s->direction & (1 << line);
 172     else
 173         s->level &= ~(s->direction & (1 << line));
 174 }
 175
 176 /* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 177  * but also accepts sequences that are not SMBus so return an I2C device.  */
 178 static int max7310_init(i2c_slave *i2c)
 179 {
 180     MAX7310State *s = FROM_I2C_SLAVE(MAX7310State, i2c);
 181
 182     qdev_init_gpio_in(&i2c->qdev, max7310_gpio_set, 8);
 183     qdev_init_gpio_out(&i2c->qdev, s->handler, 8);
 184
 185     return 0;
 186 }
 187
 188 static I2CSlaveInfo max7310_info = {
 189     .qdev.name = "max7310",
 190     .qdev.size = sizeof(MAX7310State),
 191     .qdev.vmsd = &vmstate_max7310,
 192     .qdev.reset = max7310_reset,
 193     .init = max7310_init,
 194     .event = max7310_event,
 195     .recv = max7310_rx,
 196     .send = max7310_tx
 197 };
 198
 199 static void max7310_register_devices(void)
 200 {
 201     i2c_register_slave(&max7310_info);
 202 }
 203
 204 device_init(max7310_register_devices)