I2C interface definitions

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1671 42af7a65-404d-4744-a932-0658087f49c3

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diff --git a/nuttx/include/nuttx/i2c.h b/nuttx/include/nuttx/i2c.h
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+/****************************************************************************
+ * include/nuttx/i2c.h
+ *
+ *   Copyright(C) 2009 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name NuttX 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.
+ *
+ ****************************************************************************/
+
+#ifndef __NUTTX_I2C_H
+#define __NUTTX_I2C_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <sys/types.h>
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* Access macros */
+
+/****************************************************************************
+ * Name: I2C_SETFREQUENCY
+ *
+ * Description:
+ *   Set the I2C frequency. Required.
+ *
+ * Input Parameters:
+ *   dev -       Device-specific state data
+ *   frequency - The I2C frequency requested
+ *
+ * Returned Value:
+ *   Returns the actual frequency selected
+ *
+ ****************************************************************************/
+
+#define I2C_SETFREQUENCY(d,f) ((d)->ops->setfrequency(d,f))
+
+/****************************************************************************
+ * Name: I2C_WRITE
+ *
+ * Description:
+ *   Send a block of data on I2C. Required.
+ *
+ * Input Parameters:
+ *   dev -    Device-specific state data
+ *   buffer - A pointer to the read-only buffer of data to be written to device
+ *   buflen - The number of bytes to send from the buffer
+ *
+ * Returned Value:
+ *   0: success, <0: A negated errno
+ *
+ ****************************************************************************/
+
+#define I2C_WRITE(d,b,l) ((d)->ops->sndblock(d,b,l))
+
+/****************************************************************************
+ * Name: I2C_READ
+ *
+ * Description:
+ *   Receive a block of data from I2C. Required.
+ *
+ * Input Parameters:
+ *   dev -   Device-specific state data
+ *   buffer - A pointer to a buffer of data to receive the data from the device
+ *   buflen - The requested number of bytes to be read
+ *
+ * Returned Value:
+ *   0: success, <0: A negated errno
+ *
+ ****************************************************************************/
+
+#define I2C_READ(d,b,l) ((d)->ops->sndblock(d,b,l))
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* The I2C vtable */
+
+struct i2c_dev_s;
+struct i2c_ops_s
+{
+  uint32 (*setfrequency)(FAR struct i2c_dev_s *dev, uint32 frequency);
+  int    (*write)(FAR struct i2c_dev_s *dev, int addr, const ubyte *buffer, int buflen);
+  int    (*read)(FAR struct i2c_dev_s *dev, int addr, ubyte *buffer, int buflen);
+};
+
+/* I2C private data.  This structure only defines the initial fields of the
+ * structure visible to the I2C client.  The specific implementation may 
+ * add additional, device specific fields
+ */
+
+struct i2c_dev_s
+{
+  const struct i2c_ops_s *ops;
+};
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Name: up_i2cinitialize
+ *
+ * Description:
+ *   Initialize the selected I2C port.
+ *
+ * Input Parameter:
+ *   Port number (for hardware that has mutiple I2C interfaces)
+ *
+ * Returned Value:
+ *   Valid I2C device structre reference on succcess; a NULL on failure
+ *
+ ****************************************************************************/
+
+EXTERN FAR struct i2c_dev_s *up_i2cinitialize(int port);
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+#endif /* __NUTTX_I2C_H */