root / hw / i2c.c @ a5fd2c34
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/*
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* QEMU I2C bus interface.
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*
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* Copyright (c) 2007 CodeSourcery.
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* Written by Paul Brook
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*
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* This code is licenced under the LGPL.
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*/
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#include "i2c.h" |
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struct i2c_bus
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{ |
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BusState qbus; |
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i2c_slave *current_dev; |
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i2c_slave *dev; |
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uint8_t saved_address; |
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}; |
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static struct BusInfo i2c_bus_info = { |
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.name = "I2C",
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.size = sizeof(i2c_bus),
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.props = (Property[]) { |
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DEFINE_PROP_UINT8("address", struct i2c_slave, address, 0), |
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DEFINE_PROP_END_OF_LIST(), |
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} |
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}; |
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static void i2c_bus_pre_save(void *opaque) |
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{ |
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i2c_bus *bus = opaque; |
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bus->saved_address = bus->current_dev ? bus->current_dev->address : -1;
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} |
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static int i2c_bus_post_load(void *opaque, int version_id) |
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{ |
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i2c_bus *bus = opaque; |
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/* The bus is loaded before attached devices, so load and save the
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current device id. Devices will check themselves as loaded. */
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bus->current_dev = NULL;
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return 0; |
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} |
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static const VMStateDescription vmstate_i2c_bus = { |
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.name = "i2c_bus",
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.version_id = 1,
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.minimum_version_id = 1,
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.minimum_version_id_old = 1,
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.pre_save = i2c_bus_pre_save, |
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.post_load = i2c_bus_post_load, |
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.fields = (VMStateField []) { |
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VMSTATE_UINT8(saved_address, i2c_bus), |
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VMSTATE_END_OF_LIST() |
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} |
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}; |
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/* Create a new I2C bus. */
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i2c_bus *i2c_init_bus(DeviceState *parent, const char *name) |
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{ |
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i2c_bus *bus; |
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bus = FROM_QBUS(i2c_bus, qbus_create(&i2c_bus_info, parent, name)); |
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vmstate_register(NULL, -1, &vmstate_i2c_bus, bus); |
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return bus;
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} |
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void i2c_set_slave_address(i2c_slave *dev, uint8_t address)
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{ |
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dev->address = address; |
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} |
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/* Return nonzero if bus is busy. */
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int i2c_bus_busy(i2c_bus *bus)
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{ |
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return bus->current_dev != NULL; |
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} |
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/* Returns non-zero if the address is not valid. */
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/* TODO: Make this handle multiple masters. */
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int i2c_start_transfer(i2c_bus *bus, uint8_t address, int recv) |
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{ |
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DeviceState *qdev; |
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i2c_slave *slave = NULL;
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QLIST_FOREACH(qdev, &bus->qbus.children, sibling) { |
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i2c_slave *candidate = I2C_SLAVE_FROM_QDEV(qdev); |
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if (candidate->address == address) {
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slave = candidate; |
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break;
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} |
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} |
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if (!slave)
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return 1; |
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/* If the bus is already busy, assume this is a repeated
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start condition. */
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bus->current_dev = slave; |
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slave->info->event(slave, recv ? I2C_START_RECV : I2C_START_SEND); |
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return 0; |
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} |
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void i2c_end_transfer(i2c_bus *bus)
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{ |
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i2c_slave *dev = bus->current_dev; |
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if (!dev)
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return;
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dev->info->event(dev, I2C_FINISH); |
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bus->current_dev = NULL;
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} |
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int i2c_send(i2c_bus *bus, uint8_t data)
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{ |
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i2c_slave *dev = bus->current_dev; |
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if (!dev)
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return -1; |
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return dev->info->send(dev, data);
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} |
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int i2c_recv(i2c_bus *bus)
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{ |
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i2c_slave *dev = bus->current_dev; |
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if (!dev)
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return -1; |
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return dev->info->recv(dev);
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} |
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void i2c_nack(i2c_bus *bus)
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{ |
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i2c_slave *dev = bus->current_dev; |
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if (!dev)
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return;
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dev->info->event(dev, I2C_NACK); |
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} |
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static int i2c_slave_post_load(void *opaque, int version_id) |
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{ |
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i2c_slave *dev = opaque; |
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i2c_bus *bus; |
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bus = FROM_QBUS(i2c_bus, qdev_get_parent_bus(&dev->qdev)); |
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if (bus->saved_address == dev->address) {
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bus->current_dev = dev; |
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} |
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return 0; |
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} |
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const VMStateDescription vmstate_i2c_slave = {
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.name = "i2c_slave",
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.version_id = 1,
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.minimum_version_id = 1,
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.minimum_version_id_old = 1,
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.post_load = i2c_slave_post_load, |
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.fields = (VMStateField []) { |
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VMSTATE_UINT8(address, i2c_slave), |
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VMSTATE_END_OF_LIST() |
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} |
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}; |
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static int i2c_slave_qdev_init(DeviceState *dev, DeviceInfo *base) |
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{ |
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I2CSlaveInfo *info = container_of(base, I2CSlaveInfo, qdev); |
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i2c_slave *s = I2C_SLAVE_FROM_QDEV(dev); |
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s->info = info; |
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return info->init(s);
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} |
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void i2c_register_slave(I2CSlaveInfo *info)
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{ |
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assert(info->qdev.size >= sizeof(i2c_slave));
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info->qdev.init = i2c_slave_qdev_init; |
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info->qdev.bus_info = &i2c_bus_info; |
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qdev_register(&info->qdev); |
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} |
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DeviceState *i2c_create_slave(i2c_bus *bus, const char *name, uint8_t addr) |
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{ |
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DeviceState *dev; |
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dev = qdev_create(&bus->qbus, name); |
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qdev_prop_set_uint8(dev, "address", addr);
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qdev_init_nofail(dev); |
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return dev;
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} |