dev: Add support for i2c devices

This patch adds an I2C bus and base device. I2C is used to connect a
variety of sensors, and this patch serves as a starting point to
enable a range of I2C devices.

1 files changed, 96 insertions, 0 deletions

diff --git a/src/dev/i2cdev.hh b/src/dev/i2cdev.hh
new file mode 100644
index 000000000..d101483fd
--- /dev/null
+++ b/src/dev/i2cdev.hh
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2012 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.*
+ *
+ * Authors: Peter Enns
+ */
+
+
+/** @file
+ * All i2c devices should derive from this class.
+ */
+
+#ifndef __DEV_I2CDEV__
+#define __DEV_I2CDEV__
+
+#include "base/types.hh"
+#include "params/I2CDevice.hh"
+#include "sim/sim_object.hh"
+
+class I2CDevice : public SimObject
+{
+
+  protected:
+
+    uint8_t _addr;
+
+  public:
+
+    I2CDevice(const I2CDeviceParams* p)
+        : SimObject(p), _addr(p->i2c_addr)
+    { }
+
+    virtual ~I2CDevice() { }
+
+    /**
+     * Return the next message that the device expects to send. This
+     * will likely have side effects (e.g., incrementing a register
+     * pointer).
+     *
+     * @return 8-bit message the device has been set up to send
+     */
+    virtual uint8_t read() = 0;
+
+    /**
+     * Perform any actions triggered by an i2c write (save msg in a
+     * register, perform an interrupt, update a register pointer or
+     * command register, etc...)
+     *
+     * @param msg 8-bit message from master
+     */
+    virtual void write(uint8_t msg) = 0;
+
+    /**
+     * Perform any initialization necessary for the device when it
+     * received a start signal from the bus master (devices frequently
+     * expect the first write to be a register address)
+     */
+    virtual void i2cStart() = 0;
+
+    uint8_t i2cAddr() const { return _addr; }
+
+};
+
+#endif // __DEV_I2CDEV__