I2C changes for upstream NuttX per trasaction freq control

src/platforms/px4_i2c.h

@@ -46,14 +46,17 @@
 #error "Devices not supported in ROS"
 
 #elif defined (__PX4_NUTTX)
+__BEGIN_DECLS
+
 /*
  * Building for NuttX
  */
+#include <px4_config.h>
 #include <sys/ioctl.h>
 #include <nuttx/arch.h>
 #include <nuttx/wqueue.h>
 #include <nuttx/clock.h>
-#include <nuttx/i2c.h>
+#include <nuttx/i2c/i2c_master.h>
 #include <nuttx/irq.h>
 #include <nuttx/wqueue.h>
 #include <chip.h>
@@ -64,7 +67,8 @@
 
 #define px4_i2c_msg_t i2c_msg_s
 
-typedef struct i2c_dev_s px4_i2c_dev_t;
+typedef struct i2c_master_s px4_i2c_dev_t;
+__END_DECLS
 
 #elif defined(__PX4_POSIX)
 #include <stdint.h>
@@ -74,11 +78,13 @@ typedef struct i2c_dev_s px4_i2c_dev_t;
 #define I2C_M_NORESTART      0x0080          /* message should not begin with (re-)start of transfer */
 
 // NOTE - This is a copy of the NuttX i2c_msg_s structure
+
 typedef struct {
-	uint16_t  addr;                  /* Slave address */
-	uint16_t  flags;                 /* See I2C_M_* definitions */
-	uint8_t  *buffer;
-	int       length;
+	uint32_t frequency;         /* I2C frequency */
+	uint16_t addr;              /* Slave address (7- or 10-bit) */
+	uint16_t flags;             /* See I2C_M_* definitions */
+	uint8_t *buffer;        /* Buffer to be transferred */
+	ssize_t length;             /* Length of the buffer in bytes */
 } px4_i2c_msg_t;
 
 // NOTE - This is a copy of the NuttX i2c_ops_s structure
@@ -86,10 +92,6 @@ typedef struct {
 	const struct px4_i2c_ops_t *ops; /* I2C vtable */
 } px4_i2c_dev_t;
 
-// FIXME - Empty defines for I2C ops
-// Original version commented out
-//#define I2C_SETFREQUENCY(d,f) ((d)->ops->setfrequency(d,f))
-#define I2C_SETFREQUENCY(d,f)
 //#define SPI_SELECT(d,id,s) ((d)->ops->select(d,id,s))
 #define SPI_SELECT(d,id,s)