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 "hw.h"
  11 #include "i2c.h"
  12
  13 struct max7310_s {
  14     i2c_slave i2c;
  15     int i2c_command_byte;
  16     int len;
  17
  18     uint8_t level;
  19     uint8_t direction;
  20     uint8_t polarity;
  21     uint8_t status;
  22     uint8_t command;
  23     qemu_irq handler[8];
  24     qemu_irq *gpio_in;
  25 };
  26
  27 void max7310_reset(i2c_slave *i2c)
  28 {
  29     struct max7310_s *s = (struct max7310_s *) i2c;
  30     s->level &= s->direction;
  31     s->direction = 0xff;
  32     s->polarity = 0xf0;
  33     s->status = 0x01;
  34     s->command = 0x00;
  35 }
  36
  37 static int max7310_rx(i2c_slave *i2c)
  38 {
  39     struct max7310_s *s = (struct max7310_s *) i2c;
  40
  41     switch (s->command) {
  42     case 0x00:  /* Input port */
  43         return s->level ^ s->polarity;
  44         break;
  45
  46     case 0x01:  /* Output port */
  47         return s->level & ~s->direction;
  48         break;
  49
  50     case 0x02:  /* Polarity inversion */
  51         return s->polarity;
  52
  53     case 0x03:  /* Configuration */
  54         return s->direction;
  55
  56     case 0x04:  /* Timeout */
  57         return s->status;
  58         break;
  59
  60     case 0xff:  /* Reserved */
  61         return 0xff;
  62
  63     default:
  64 #ifdef VERBOSE
  65         printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
  66 #endif
  67         break;
  68     }
  69     return 0xff;
  70 }
  71
  72 static int max7310_tx(i2c_slave *i2c, uint8_t data)
  73 {
  74     struct max7310_s *s = (struct max7310_s *) i2c;
  75     uint8_t diff;
  76     int line;
  77
  78     if (s->len ++ > 1) {
  79 #ifdef VERBOSE
  80         printf("%s: message too long (%i bytes)\n", __FUNCTION__, s->len);
  81 #endif
  82         return 1;
  83     }
  84
  85     if (s->i2c_command_byte) {
  86         s->command = data;
  87         s->i2c_command_byte = 0;
  88         return 0;
  89     }
  90
  91     switch (s->command) {
  92     case 0x01:  /* Output port */
  93         for (diff = (data ^ s->level) & ~s->direction; diff;
  94                         diff &= ~(1 << line)) {
  95             line = ffs(diff) - 1;
  96             if (s->handler[line])
  97                 qemu_set_irq(s->handler[line], (data >> line) & 1);
  98         }
  99         s->level = (s->level & s->direction) | (data & ~s->direction);
 100         break;
 101
 102     case 0x02:  /* Polarity inversion */
 103         s->polarity = data;
 104         break;
 105
 106     case 0x03:  /* Configuration */
 107         s->level &= ~(s->direction ^ data);
 108         s->direction = data;
 109         break;
 110
 111     case 0x04:  /* Timeout */
 112         s->status = data;
 113         break;
 114
 115     case 0x00:  /* Input port - ignore writes */
 116         break;
 117     default:
 118 #ifdef VERBOSE
 119         printf("%s: unknown register %02x\n", __FUNCTION__, s->command);
 120 #endif
 121         return 1;
 122     }
 123
 124     return 0;
 125 }
 126
 127 static void max7310_event(i2c_slave *i2c, enum i2c_event event)
 128 {
 129     struct max7310_s *s = (struct max7310_s *) i2c;
 130     s->len = 0;
 131
 132     switch (event) {
 133     case I2C_START_SEND:
 134         s->i2c_command_byte = 1;
 135         break;
 136     case I2C_FINISH:
 137 #ifdef VERBOSE
 138         if (s->len == 1)
 139             printf("%s: message too short (%i bytes)\n", __FUNCTION__, s->len);
 140 #endif
 141         break;
 142     default:
 143         break;
 144     }
 145 }
 146
 147 static void max7310_save(QEMUFile *f, void *opaque)
 148 {
 149     struct max7310_s *s = (struct max7310_s *) opaque;
 150
 151     qemu_put_be32(f, s->i2c_command_byte);
 152     qemu_put_be32(f, s->len);
 153
 154     qemu_put_8s(f, &s->level);
 155     qemu_put_8s(f, &s->direction);
 156     qemu_put_8s(f, &s->polarity);
 157     qemu_put_8s(f, &s->status);
 158     qemu_put_8s(f, &s->command);
 159
 160     i2c_slave_save(f, &s->i2c);
 161 }
 162
 163 static int max7310_load(QEMUFile *f, void *opaque, int version_id)
 164 {
 165     struct max7310_s *s = (struct max7310_s *) opaque;
 166
 167     s->i2c_command_byte = qemu_get_be32(f);
 168     s->len = qemu_get_be32(f);
 169
 170     qemu_get_8s(f, &s->level);
 171     qemu_get_8s(f, &s->direction);
 172     qemu_get_8s(f, &s->polarity);
 173     qemu_get_8s(f, &s->status);
 174     qemu_get_8s(f, &s->command);
 175
 176     i2c_slave_load(f, &s->i2c);
 177     return 0;
 178 }
 179
 180 static void max7310_gpio_set(void *opaque, int line, int level)
 181 {
 182     struct max7310_s *s = (struct max7310_s *) opaque;
 183     if (line >= sizeof(s->handler) / sizeof(*s->handler) || line  < 0)
 184         hw_error("bad GPIO line");
 185
 186     if (level)
 187         s->level |= s->direction & (1 << line);
 188     else
 189         s->level &= ~(s->direction & (1 << line));
 190 }
 191
 192 /* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 193  * but also accepts sequences that are not SMBus so return an I2C device.  */
 194 struct i2c_slave *max7310_init(i2c_bus *bus)
 195 {
 196     struct max7310_s *s = (struct max7310_s *)
 197             i2c_slave_init(bus, 0, sizeof(struct max7310_s));
 198     s->i2c.event = max7310_event;
 199     s->i2c.recv = max7310_rx;
 200     s->i2c.send = max7310_tx;
 201     s->gpio_in = qemu_allocate_irqs(max7310_gpio_set, s,
 202                     sizeof(s->handler) / sizeof(*s->handler));
 203
 204     max7310_reset(&s->i2c);
 205
 206     register_savevm("max7310", -1, 0, max7310_save, max7310_load, s);
 207
 208     return &s->i2c;
 209 }
 210
 211 qemu_irq *max7310_gpio_in_get(i2c_slave *i2c)
 212 {
 213     struct max7310_s *s = (struct max7310_s *) i2c;
 214     return s->gpio_in;
 215 }
 216
 217 void max7310_gpio_out_set(i2c_slave *i2c, int line, qemu_irq handler)
 218 {
 219     struct max7310_s *s = (struct max7310_s *) i2c;
 220     if (line >= sizeof(s->handler) / sizeof(*s->handler) || line  < 0)
 221         hw_error("bad GPIO line");
 222
 223     s->handler[line] = handler;
 224 }