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/*
* QEMU I2C bus interface.
*
* Copyright (c) 2007 CodeSourcery.
* Written by Paul Brook
*
* This code is licensed under the LGPL.
*/
#include "i2c.h"
struct i2c_bus
{
BusState qbus;
I2CSlave *current_dev;
I2CSlave *dev;
uint8_t saved_address;
};
static struct BusInfo i2c_bus_info = {
.name = "I2C",
.size = sizeof(i2c_bus),
.props = (Property[]) {
DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0),
DEFINE_PROP_END_OF_LIST(),
}
};
static void i2c_bus_pre_save(void *opaque)
{
i2c_bus *bus = opaque;
bus->saved_address = bus->current_dev ? bus->current_dev->address : -1;
}
static int i2c_bus_post_load(void *opaque, int version_id)
{
i2c_bus *bus = opaque;
/* The bus is loaded before attached devices, so load and save the
current device id. Devices will check themselves as loaded. */
bus->current_dev = NULL;
return 0;
}
static const VMStateDescription vmstate_i2c_bus = {
.name = "i2c_bus",
.version_id = 1,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.pre_save = i2c_bus_pre_save,
.post_load = i2c_bus_post_load,
.fields = (VMStateField []) {
VMSTATE_UINT8(saved_address, i2c_bus),
VMSTATE_END_OF_LIST()
}
};
/* Create a new I2C bus. */
i2c_bus *i2c_init_bus(DeviceState *parent, const char *name)
{
i2c_bus *bus;
bus = FROM_QBUS(i2c_bus, qbus_create(&i2c_bus_info, parent, name));
vmstate_register(NULL, -1, &vmstate_i2c_bus, bus);
return bus;
}
void i2c_set_slave_address(I2CSlave *dev, uint8_t address)
{
dev->address = address;
}
/* Return nonzero if bus is busy. */
int i2c_bus_busy(i2c_bus *bus)
{
return bus->current_dev != NULL;
}
/* Returns non-zero if the address is not valid. */
/* TODO: Make this handle multiple masters. */
int i2c_start_transfer(i2c_bus *bus, uint8_t address, int recv)
{
DeviceState *qdev;
I2CSlave *slave = NULL;
QTAILQ_FOREACH(qdev, &bus->qbus.children, sibling) {
I2CSlave *candidate = I2C_SLAVE_FROM_QDEV(qdev);
if (candidate->address == address) {
slave = candidate;
break;
}
}
if (!slave)
return 1;
/* If the bus is already busy, assume this is a repeated
start condition. */
bus->current_dev = slave;
slave->info->event(slave, recv ? I2C_START_RECV : I2C_START_SEND);
return 0;
}
void i2c_end_transfer(i2c_bus *bus)
{
I2CSlave *dev = bus->current_dev;
if (!dev)
return;
dev->info->event(dev, I2C_FINISH);
bus->current_dev = NULL;
}
int i2c_send(i2c_bus *bus, uint8_t data)
{
I2CSlave *dev = bus->current_dev;
if (!dev)
return -1;
return dev->info->send(dev, data);
}
int i2c_recv(i2c_bus *bus)
{
I2CSlave *dev = bus->current_dev;
if (!dev)
return -1;
return dev->info->recv(dev);
}
void i2c_nack(i2c_bus *bus)
{
I2CSlave *dev = bus->current_dev;
if (!dev)
return;
dev->info->event(dev, I2C_NACK);
}
static int i2c_slave_post_load(void *opaque, int version_id)
{
I2CSlave *dev = opaque;
i2c_bus *bus;
bus = FROM_QBUS(i2c_bus, qdev_get_parent_bus(&dev->qdev));
if (bus->saved_address == dev->address) {
bus->current_dev = dev;
}
return 0;
}
const VMStateDescription vmstate_i2c_slave = {
.name = "I2CSlave",
.version_id = 1,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.post_load = i2c_slave_post_load,
.fields = (VMStateField []) {
VMSTATE_UINT8(address, I2CSlave),
VMSTATE_END_OF_LIST()
}
};
static int i2c_slave_qdev_init(DeviceState *dev, DeviceInfo *base)
{
I2CSlaveInfo *info = container_of(base, I2CSlaveInfo, qdev);
I2CSlave *s = I2C_SLAVE_FROM_QDEV(dev);
s->info = info;
return info->init(s);
}
void i2c_register_slave(I2CSlaveInfo *info)
{
assert(info->qdev.size >= sizeof(I2CSlave));
info->qdev.init = i2c_slave_qdev_init;
info->qdev.bus_info = &i2c_bus_info;
qdev_register(&info->qdev);
}
DeviceState *i2c_create_slave(i2c_bus *bus, const char *name, uint8_t addr)
{
DeviceState *dev;
dev = qdev_create(&bus->qbus, name);
qdev_prop_set_uint8(dev, "address", addr);
qdev_init_nofail(dev);
return dev;
}
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