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authorpbrook <pbrook@c046a42c-6fe2-441c-8c8c-71466251a162>2007-05-23 00:03:59 +0000
committerpbrook <pbrook@c046a42c-6fe2-441c-8c8c-71466251a162>2007-05-23 00:03:59 +0000
commit0ff596d02fd9d876a31d038255a6d4f89da9dfed (patch)
tree754c9dfaee7006ab91d80333141835d9213a6d06 /hw/i2c.c
parentc6fdf5fca0149fbc2d05d8d5ad43e3686c37514e (diff)
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I2C/SMBus framework.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2845 c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'hw/i2c.c')
-rw-r--r--hw/i2c.c117
1 files changed, 117 insertions, 0 deletions
diff --git a/hw/i2c.c b/hw/i2c.c
new file mode 100644
index 0000000..5d9319d
--- /dev/null
+++ b/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);
+}
+