I2C/SMBus framework.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2845 c046a42c-6fe2-441c-8c8c-71466251a162

hw/i2c.c

@@ -0,0 +1,117 @@
+/* 
+ * QEMU I2C bus interface.
+ *
+ * Copyright (c) 2007 CodeSourcery.
+ * Written by Paul Brook
+ *
+ * This code is licenced under the LGPL.
+ */
+
+#include "vl.h"
+
+struct i2c_bus
+{
+    i2c_slave *current_dev;
+    i2c_slave *dev;
+};
+
+/* Create a new I2C bus.  */
+i2c_bus *i2c_init_bus(void)
+{
+    i2c_bus *bus;
+
+    bus = (i2c_bus *)qemu_mallocz(sizeof(i2c_bus));
+    return bus;
+}
+
+/* Create a new slave device.  */
+i2c_slave *i2c_slave_init(i2c_bus *bus, int address, int size)
+{
+    i2c_slave *dev;
+
+    if (size < sizeof(i2c_slave))
+        cpu_abort(cpu_single_env, "I2C struct too small");
+
+    dev = (i2c_slave *)qemu_mallocz(size);
+    dev->address = address;
+    dev->next = bus->dev;
+    bus->dev = dev;
+
+    return dev;
+}
+
+void i2c_set_slave_address(i2c_slave *dev, int address)
+{
+    dev->address = address;
+}
+
+/* Return nonzero if bus is busy.  */
+int i2c_bus_busy(i2c_bus *bus)
+{
+    return bus->current_dev != NULL;
+}
+
+/* Returns nonzero if the bus is already busy, or is the address is not
+   valid.  */
+/* TODO: Make this handle multiple masters.  */
+int i2c_start_transfer(i2c_bus *bus, int address, int recv)
+{
+    i2c_slave *dev;
+
+    for (dev = bus->dev; dev; dev = dev->next) {
+        if (dev->address == address)
+            break;
+    }
+
+    if (!dev)
+        return 1;
+
+    /* If the bus is already busy, assume this is a repeated
+       start condition.  */
+    bus->current_dev = dev;
+    dev->event(dev, recv ? I2C_START_RECV : I2C_START_SEND);
+    return 0;
+}
+
+void i2c_end_transfer(i2c_bus *bus)
+{
+    i2c_slave *dev = bus->current_dev;
+
+    if (!dev)
+        return;
+
+    dev->event(dev, I2C_FINISH);
+
+    bus->current_dev = NULL;
+}
+
+int i2c_send(i2c_bus *bus, uint8_t data)
+{
+    i2c_slave *dev = bus->current_dev;
+
+    if (!dev)
+        return -1;
+
+    return dev->send(dev, data);
+}
+
+int i2c_recv(i2c_bus *bus)
+{
+    i2c_slave *dev = bus->current_dev;
+
+    if (!dev)
+        return -1;
+
+    return dev->recv(dev);
+}
+
+void i2c_nack(i2c_bus *bus)
+{
+    i2c_slave *dev = bus->current_dev;
+
+    if (!dev)
+        return;
+
+    dev->event(dev, I2C_NACK);
+}
+