root / hw / i2c.c @ cae4956e
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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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int saved_address;
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}; |
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static void i2c_bus_save(QEMUFile *f, void *opaque) |
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{ |
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i2c_bus *bus = (i2c_bus *)opaque; |
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qemu_put_byte(f, bus->current_dev ? bus->current_dev->address : -1);
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} |
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static int i2c_bus_load(QEMUFile *f, void *opaque, int version_id) |
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{ |
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i2c_bus *bus = (i2c_bus *)opaque; |
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if (version_id != 1) |
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return -EINVAL;
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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->saved_address = (int8_t) qemu_get_byte(f); |
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bus->current_dev = NULL;
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return 0; |
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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(BUS_TYPE_I2C, sizeof(i2c_bus),
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parent, name)); |
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register_savevm("i2c_bus", -1, 1, i2c_bus_save, i2c_bus_load, bus); |
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return bus;
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} |
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void i2c_set_slave_address(i2c_slave *dev, int 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, int 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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LIST_FOREACH(qdev, &bus->qbus.children, sibling) { |
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slave = I2C_SLAVE_FROM_QDEV(qdev); |
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if (slave->address == address)
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break;
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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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void i2c_slave_save(QEMUFile *f, i2c_slave *dev)
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{ |
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qemu_put_byte(f, dev->address); |
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} |
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void i2c_slave_load(QEMUFile *f, i2c_slave *dev)
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{ |
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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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dev->address = qemu_get_byte(f); |
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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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} |
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static void 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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s->address = qdev_get_prop_int(dev, "address", 0); |
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info->init(s); |
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} |
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void i2c_register_slave(const char *name, int size, I2CSlaveInfo *info) |
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{ |
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assert(size >= sizeof(i2c_slave));
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info->qdev.init = i2c_slave_qdev_init; |
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info->qdev.bus_type = BUS_TYPE_I2C; |
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qdev_register(name, size, &info->qdev); |
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} |
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DeviceState *i2c_create_slave(i2c_bus *bus, const char *name, int 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_set_prop_int(dev, "address", addr);
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qdev_init(dev); |
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return dev;
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} |