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 "qemu/osdep.h"
  25 #include "hw/sysbus.h"
  26 #include "bitbang_i2c.h"
  27 #include "qemu/log.h"
  28 #include "qemu/module.h"
  29
  30 #define TYPE_VERSATILE_I2C "versatile_i2c"
  31 #define VERSATILE_I2C(obj) \
  32     OBJECT_CHECK(VersatileI2CState, (obj), TYPE_VERSATILE_I2C)
  33
  34 typedef struct VersatileI2CState {
  35     SysBusDevice parent_obj;
  36
  37     MemoryRegion iomem;
  38     bitbang_i2c_interface *bitbang;
  39     int out;
  40     int in;
  41 } VersatileI2CState;
  42
  43 static uint64_t versatile_i2c_read(void *opaque, hwaddr offset,
  44                                    unsigned size)
  45 {
  46     VersatileI2CState *s = (VersatileI2CState *)opaque;
  47
  48     if (offset == 0) {
  49         return (s->out & 1) | (s->in << 1);
  50     } else {
  51         qemu_log_mask(LOG_GUEST_ERROR,
  52                       "%s: Bad offset 0x%x\n", __func__, (int)offset);
  53         return -1;
  54     }
  55 }
  56
  57 static void versatile_i2c_write(void *opaque, hwaddr offset,
  58                                 uint64_t value, unsigned size)
  59 {
  60     VersatileI2CState *s = (VersatileI2CState *)opaque;
  61
  62     switch (offset) {
  63     case 0:
  64         s->out |= value & 3;
  65         break;
  66     case 4:
  67         s->out &= ~value;
  68         break;
  69     default:
  70         qemu_log_mask(LOG_GUEST_ERROR,
  71                       "%s: Bad offset 0x%x\n", __func__, (int)offset);
  72     }
  73     bitbang_i2c_set(s->bitbang, BITBANG_I2C_SCL, (s->out & 1) != 0);
  74     s->in = bitbang_i2c_set(s->bitbang, BITBANG_I2C_SDA, (s->out & 2) != 0);
  75 }
  76
  77 static const MemoryRegionOps versatile_i2c_ops = {
  78     .read = versatile_i2c_read,
  79     .write = versatile_i2c_write,
  80     .endianness = DEVICE_NATIVE_ENDIAN,
  81 };
  82
  83 static void versatile_i2c_init(Object *obj)
  84 {
  85     DeviceState *dev = DEVICE(obj);
  86     VersatileI2CState *s = VERSATILE_I2C(obj);
  87     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
  88     I2CBus *bus;
  89
  90     bus = i2c_init_bus(dev, "i2c");
  91     s->bitbang = bitbang_i2c_init(bus);
  92     memory_region_init_io(&s->iomem, obj, &versatile_i2c_ops, s,
  93                           "versatile_i2c", 0x1000);
  94     sysbus_init_mmio(sbd, &s->iomem);
  95 }
  96
  97 static const TypeInfo versatile_i2c_info = {
  98     .name          = TYPE_VERSATILE_I2C,
  99     .parent        = TYPE_SYS_BUS_DEVICE,
 100     .instance_size = sizeof(VersatileI2CState),
 101     .instance_init = versatile_i2c_init,
 102 };
 103
 104 static void versatile_i2c_register_types(void)
 105 {
 106     type_register_static(&versatile_i2c_info);
 107 }
 108
 109 type_init(versatile_i2c_register_types)