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 "vl.h"
  11
  12 struct max7310_s {
  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 };
  25
  26 void max7310_reset(i2c_slave *i2c)
  27 {
  28     struct max7310_s *s = (struct max7310_s *) i2c;
  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     struct max7310_s *s = (struct max7310_s *) 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     struct max7310_s *s = (struct max7310_s *) 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     struct max7310_s *s = (struct max7310_s *) 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         if (s->len == 1)
 137 #ifdef VERBOSE
 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 void max7310_save(QEMUFile *f, void *opaque)
 147 {
 148     struct max7310_s *s = (struct max7310_s *) opaque;
 149
 150     qemu_put_be32(f, s->i2c_command_byte);
 151     qemu_put_be32(f, s->len);
 152
 153     qemu_put_8s(f, &s->level);
 154     qemu_put_8s(f, &s->direction);
 155     qemu_put_8s(f, &s->polarity);
 156     qemu_put_8s(f, &s->status);
 157     qemu_put_8s(f, &s->command);
 158
 159     i2c_slave_save(f, &s->i2c);
 160 }
 161
 162 static int max7310_load(QEMUFile *f, void *opaque, int version_id)
 163 {
 164     struct max7310_s *s = (struct max7310_s *) opaque;
 165
 166     s->i2c_command_byte = qemu_get_be32(f);
 167     s->len = qemu_get_be32(f);
 168
 169     qemu_get_8s(f, &s->level);
 170     qemu_get_8s(f, &s->direction);
 171     qemu_get_8s(f, &s->polarity);
 172     qemu_get_8s(f, &s->status);
 173     qemu_get_8s(f, &s->command);
 174
 175     i2c_slave_load(f, &s->i2c);
 176     return 0;
 177 }
 178
 179 static int max7310_iid = 0;
 180
 181 static void max7310_gpio_set(void *opaque, int line, int level)
 182 {
 183     struct max7310_s *s = (struct max7310_s *) opaque;
 184     if (line >= sizeof(s->handler) / sizeof(*s->handler) || line  < 0)
 185         cpu_abort(cpu_single_env, "bad GPIO line");
 186
 187     if (level)
 188         s->level |= s->direction & (1 << line);
 189     else
 190         s->level &= ~(s->direction & (1 << line));
 191 }
 192
 193 /* MAX7310 is SMBus-compatible (can be used with only SMBus protocols),
 194  * but also accepts sequences that are not SMBus so return an I2C device.  */
 195 struct i2c_slave *max7310_init(i2c_bus *bus)
 196 {
 197     struct max7310_s *s = (struct max7310_s *)
 198             i2c_slave_init(bus, 0, sizeof(struct max7310_s));
 199     s->i2c.event = max7310_event;
 200     s->i2c.recv = max7310_rx;
 201     s->i2c.send = max7310_tx;
 202     s->gpio_in = qemu_allocate_irqs(max7310_gpio_set, s,
 203                     sizeof(s->handler) / sizeof(*s->handler));
 204
 205     max7310_reset(&s->i2c);
 206
 207     register_savevm("max7310", max7310_iid ++, 0,
 208                     max7310_save, max7310_load, s);
 209
 210     return &s->i2c;
 211 }
 212
 213 qemu_irq *max7310_gpio_in_get(i2c_slave *i2c)
 214 {
 215     struct max7310_s *s = (struct max7310_s *) i2c;
 216     return s->gpio_in;
 217 }
 218
 219 void max7310_gpio_out_set(i2c_slave *i2c, int line, qemu_irq handler)
 220 {
 221     struct max7310_s *s = (struct max7310_s *) i2c;
 222     if (line >= sizeof(s->handler) / sizeof(*s->handler) || line  < 0)
 223         cpu_abort(cpu_single_env, "bad GPIO line");
 224
 225     s->handler[line] = handler;
 226 }