hw/i2c/versatile_i2c.c

   1 /*
   2  * ARM Versatile I2C controller
   3  *
   4  * Copyright (c) 2006-2007 CodeSourcery.
   5  * Copyright (c) 2012 Oskar Andero <oskar.andero@gmail.com>
   6  *
   7  * This file is derived from hw/realview.c by Paul Brook
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version 2
  12  * of the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  21  *
  22  */
  23
  24 #include "hw/sysbus.h"
  25 #include "bitbang_i2c.h"
  26
  27 #define TYPE_VERSATILE_I2C "versatile_i2c"
  28 #define VERSATILE_I2C(obj) \
  29     OBJECT_CHECK(VersatileI2CState, (obj), TYPE_VERSATILE_I2C)
  30
  31 typedef struct VersatileI2CState {
  32     SysBusDevice parent_obj;
  33
  34     MemoryRegion iomem;
  35     bitbang_i2c_interface *bitbang;
  36     int out;
  37     int in;
  38 } VersatileI2CState;
  39
  40 static uint64_t versatile_i2c_read(void *opaque, hwaddr offset,
  41                                    unsigned size)
  42 {
  43     VersatileI2CState *s = (VersatileI2CState *)opaque;
  44
  45     if (offset == 0) {
  46         return (s->out & 1) | (s->in << 1);
  47     } else {
  48         qemu_log_mask(LOG_GUEST_ERROR,
  49                       "%s: Bad offset 0x%x\n", __func__, (int)offset);
  50         return -1;
  51     }
  52 }
  53
  54 static void versatile_i2c_write(void *opaque, hwaddr offset,
  55                                 uint64_t value, unsigned size)
  56 {
  57     VersatileI2CState *s = (VersatileI2CState *)opaque;
  58
  59     switch (offset) {
  60     case 0:
  61         s->out |= value & 3;
  62         break;
  63     case 4:
  64         s->out &= ~value;
  65         break;
  66     default:
  67         qemu_log_mask(LOG_GUEST_ERROR,
  68                       "%s: Bad offset 0x%x\n", __func__, (int)offset);
  69     }
  70     bitbang_i2c_set(s->bitbang, BITBANG_I2C_SCL, (s->out & 1) != 0);
  71     s->in = bitbang_i2c_set(s->bitbang, BITBANG_I2C_SDA, (s->out & 2) != 0);
  72 }
  73
  74 static const MemoryRegionOps versatile_i2c_ops = {
  75     .read = versatile_i2c_read,
  76     .write = versatile_i2c_write,
  77     .endianness = DEVICE_NATIVE_ENDIAN,
  78 };
  79
  80 static int versatile_i2c_init(SysBusDevice *sbd)
  81 {
  82     DeviceState *dev = DEVICE(sbd);
  83     VersatileI2CState *s = VERSATILE_I2C(dev);
  84     I2CBus *bus;
  85
  86     bus = i2c_init_bus(dev, "i2c");
  87     s->bitbang = bitbang_i2c_init(bus);
  88     memory_region_init_io(&s->iomem, OBJECT(s), &versatile_i2c_ops, s,
  89                           "versatile_i2c", 0x1000);
  90     sysbus_init_mmio(sbd, &s->iomem);
  91     return 0;
  92 }
  93
  94 static void versatile_i2c_class_init(ObjectClass *klass, void *data)
  95 {
  96     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
  97
  98     k->init = versatile_i2c_init;
  99 }
 100
 101 static const TypeInfo versatile_i2c_info = {
 102     .name          = TYPE_VERSATILE_I2C,
 103     .parent        = TYPE_SYS_BUS_DEVICE,
 104     .instance_size = sizeof(VersatileI2CState),
 105     .class_init    = versatile_i2c_class_init,
 106 };
 107
 108 static void versatile_i2c_register_types(void)
 109 {
 110     type_register_static(&versatile_i2c_info);
 111 }
 112
 113 type_init(versatile_i2c_register_types)