diff --git a/ChangeLog b/ChangeLog
index d1930acca63..41bf078fdca 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -11372,4 +11372,6 @@
 	* drivers/i2c/i2c_writeread.c:  Create a wrapper that uses I2C_TRANSFER
 	  to implement I2C_WRITEREAD functionality (2016-01-26).
 	* I2C: Eliminate the I@C_WRITEREAD method (2016-01-26).
+	* drivers/i2c/i2c_read.c and i2c_write.c: Convert to use I2C_TRANSFER vs.
+	  I2C_READ and I2C_WRITE which are not thread safe (2016-01-26).
 
diff --git a/drivers/ioexpander/pca9555.c b/drivers/ioexpander/pca9555.c
index 5d3843d7eaf..9f3fe58ebfb 100644
--- a/drivers/ioexpander/pca9555.c
+++ b/drivers/ioexpander/pca9555.c
@@ -72,7 +72,9 @@
  * Private Function Prototypes
  ****************************************************************************/
 
-static int pca9555_writeread(FAR struct pca9555_dev_s *pca,
+static inline int pca9555_write(FAR struct pca9555_dev_s *pca,
+             FAR const uint8_t *wbuffer, int wbuflen);
+static inline int pca9555_writeread(FAR struct pca9555_dev_s *pca,
              FAR const uint8_t *wbuffer, int wbuflen, FAR uint8_t *rbuffer,
              int rbuflen);
 static int pca9555_direction(FAR struct ioexpander_dev_s *dev, uint8_t pin,
@@ -129,6 +131,28 @@ static const struct ioexpander_ops_s g_pca9555_ops =
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: pca9555_writeread
+ *
+ * Description:
+ *   Write to then read from the I2C device.
+ *
+ ****************************************************************************/
+
+static inline int pca9555_write(FAR struct pca9555_dev_s *pca,
+                                FAR const uint8_t *wbuffer, int wbuflen)
+{
+  struct i2c_config_s config;
+
+  /* Set up the configuration and perform the write-read operation */
+
+  config.frequency = pca->config->frequency;
+  config.address   = pca->config->address;
+  config.addrlen   = 7;
+
+  return i2c_write(pca->i2c, &config, wbuffer, wbuflen);
+}
+
 /****************************************************************************
  * Name: pca9555_writeread
  *
@@ -194,7 +218,7 @@ static int pca9555_setbit(FAR struct ioexpander_dev_s *dev, uint8_t addr,
       buf[1] &= ~(1 << pin);
     }
 
-  return I2C_WRITE(pca->i2c, buf, 2);
+  return pca9555_write(pca, buf, 2);
 }
 
 /****************************************************************************
@@ -418,7 +442,7 @@ static int pca9555_multiwritepin(FAR struct ioexpander_dev_s *dev,
   /* Now write back the new pins states */
 
   buf[0] = addr;
-  return I2C_WRITE(pca->i2c, buf, 3);
+  return pca9555_write(pca, buf, 3);
 }
 
 /****************************************************************************