Add driver for LM-75 temperature sensor

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3947 42af7a65-404d-4744-a932-0658087f49c3

18 files changed, 1125 insertions, 321 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 0e168cb6f..5728cecca 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -2022,7 +2022,9 @@
 	* graphics/, include/nuttx/nx:  Add new NX interfaces for drawing
 	  circles -- both circular outlines and filled circles.
 	* graphic/nxglib/nxglib_spitline.c:  Add a "fudge factor" that eliminates
-	  some problems for rendering nearly horizontal, wide lines.
+	  some problems for rendering nearly horizontal, wide lines.  Hmm...
+	  but I suspect this fudge factor also leads to new problems rendering
+	  very thin, nearly horizontal lines.  More tuning is needed.
 	* drivers/analog, include/nuttx/analog, arch/arch/src/lpcxx:  (1) Add
 	  updates to the ADS1255 driver, (2) fix errors from my last merge (sorry),
 	  (3) Add DAC infrastructure, (4) add AD5410 DAC driver, and (5) add
@@ -2031,7 +2033,7 @@
 	  'make export' logic.  The script now also finds and bundles up all of
 	  the architecture-specific header files as well.
 	* drivers/arch/arm/src/stm32/stm32_i2c.c:  Add a reset to the I2C
-	  initialization logic to prevent spurious interrups when the I2C
+	  initialization logic to prevent spurious interrupts when the I2C
 	  interrupts are enabled (submitted by Uros Platise).
 	* Scripts/makefiles/documents.  Several adjustments, corrections and
 	  typo fixes so that NuttX will build correctly on FreeBSD using the
@@ -2064,3 +2066,7 @@
 	  (1) Clocking needs to be based on PCLK1, not HCLK and fast speed settings
 	  need some additional bits; and (2) Correct a hang that will occur on
 	  I2C1 if FSMC is also enabled.
+	* drivers/sensors/lm75.c and include/nuttx/sensors/lm75.h:  Add an LM-75
+	  temperature sensor driver.
+	* configs/stm3210e-eval/src/up_lm75.c:  Add support for the LM-75 on the
+	  STMicro STM3210E-EVAL board.
diff --git a/nuttx/TODO b/nuttx/TODO
index 719c40329..5eba13ace 100644
--- a/nuttx/TODO
+++ b/nuttx/TODO
@@ -1,12 +1,15 @@
-NuttX TODO List (Last updated August 24, 2011)
+NuttX TODO List (Last updated September 9, 2011)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+This file summarizes known NuttX bugs, limitations, inconsistencies with 
+standards, things that could be improved, and ideas for enhancements.
+
 nuttx/
 
   (5)  Task/Scheduler (sched/)
   (1)  On-demand paging (sched/)
   (1)  Memory Managment (mm/)
-  (1)  Signals (sched/, arch/)
+  (2)  Signals (sched/, arch/)
   (1)  pthreads (sched/)
   (1)  C++ Support
   (5)  Binary loaders (binfmt/)
@@ -132,6 +135,13 @@ o Signals (sched/, arch/)
   Priority:    Low, required by standards but not so critical for an
                embedded system.
 
+  Description: sig_notify() logic does not support SIGEV_THREAD; structure
+               struct sigevent does not provide required members sigev_notify_function
+               or sigev_notify_attributes.
+  Status:      Low, there are alternative designs.  However, these features
+               are required by the POSIX standard.
+  Priority:    Low for now
+
 o pthreads (sched/)
   ^^^^^^^^^^^^^^^^^
 
diff --git a/nuttx/arch/arm/src/stm32/stm32_i2c.c b/nuttx/arch/arm/src/stm32/stm32_i2c.c
index 92663363a..15f22e602 100644
--- a/nuttx/arch/arm/src/stm32/stm32_i2c.c
+++ b/nuttx/arch/arm/src/stm32/stm32_i2c.c
@@ -934,41 +934,55 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int
 
   /* Check for error status conditions */
 
-  if (status & I2C_SR1_BERR)
+  if ((status & I2C_SR1_ERRORMASK) != 0)
     {
-      /* Bus Error */
+      if (status & I2C_SR1_BERR)
+        {
+          /* Bus Error */
 
-      status_errno = EIO;
-    }
-  else if (status & I2C_SR1_ARLO)
-    {
-      /* Arbitration Lost (master mode) */
+          status_errno = EIO;
+        }
+      else if (status & I2C_SR1_ARLO)
+        {
+          /* Arbitration Lost (master mode) */
 
-      status_errno = EAGAIN;
-    }
-  else if (status & I2C_SR1_AF)
-    {
-      /* Acknowledge Failure */
+          status_errno = EAGAIN;
+        }
+      else if (status & I2C_SR1_AF)
+        {
+          /* Acknowledge Failure */
 
-      status_errno = ENXIO;
-    }
-  else if (status & I2C_SR1_OVR)
-    {
-      /* Overrun/Underrun */
+          status_errno = ENXIO;
+        }
+      else if (status & I2C_SR1_OVR)
+        {
+          /* Overrun/Underrun */
 
-      status_errno = EIO;
-    }
-  else if (status & I2C_SR1_PECERR)
-    {
-      /* PEC Error in reception */
+          status_errno = EIO;
+        }
+      else if (status & I2C_SR1_PECERR)
+        {
+          /* PEC Error in reception */
 
-      status_errno = EPROTO;
-    }
-  else if (status & I2C_SR1_TIMEOUT)
-    {
-      /* Timeout or Tlow Error */
+          status_errno = EPROTO;
+        }
+      else if (status & I2C_SR1_TIMEOUT)
+        {
+          /* Timeout or Tlow Error */
 
-      status_errno = ETIME;
+          status_errno = ETIME;
+        }
+
+      /* This is not an error and should never happen since SMBus is not enabled */
+
+      else if (status & I2C_SR1_SMBALERT)
+        {
+          /* SMBus alert is an optional signal with an interrupt line for devices
+           * that want to trade their ability to master for a pin.
+           */
+
+          status_errno = EINTR;
+        }
     }
 
   /* This is not an error, but should not happen.  The BUSY signal can hang,
@@ -982,17 +996,6 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int
       status_errno = EBUSY;
     }
 
-  /* This is not an error and should never happen since SMBus is not enabled */
-
-  else if (status & I2C_SR1_SMBALERT)
-    {
-      /* SMBus alert is an optional signal with an interrupt line for devices
-       * that want to trade their ability to master for a pin.
-       */
-
-      status_errno = EINTR;
-    }
-
   /* Re-enable the FSMC */
 
   stm32_i2c_enablefsmc(ahbenr);
diff --git a/nuttx/configs/stm3210e-eval/include/board.h b/nuttx/configs/stm3210e-eval/include/board.h
index 3c7a655f3..d8e506e6d 100755
--- a/nuttx/configs/stm3210e-eval/include/board.h
+++ b/nuttx/configs/stm3210e-eval/include/board.h
@@ -255,6 +255,42 @@ EXTERN xcpt_t up_irqbutton(int id, xcpt_t irqhandler);
 EXTERN void stm3210e_lcdclear(uint16_t color);
 #endif
 
+/************************************************************************************
+ * Name: stm32_lm75initialize
+ *
+ * Description:
+ *   Initialize and register the LM-75 Temperature Sensor driver.
+ *
+ * Input parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/temp0"
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ************************************************************************************/
+
+#if defined(CONFIG_I2C) && defined(CONFIG_I2C_LM75) && defined(CONFIG_STM32_I2C1)
+EXTERN int stm32_lm75initialize(FAR const char *devpath);
+#endif
+
+/************************************************************************************
+ * Name: stm32_lm75attach
+ *
+ * Description:
+ *   Attach the LM-75 interrupt handler
+ *
+ * Input parameters:
+ *   irqhandler - the LM-75 interrupt handler
+ *
+ * Returned Value:
+ *   The previous LM-75 interrupt handler
+ *
+ ************************************************************************************/
+
+#if defined(CONFIG_I2C) && defined(CONFIG_I2C_LM75) && defined(CONFIG_STM32_I2C1)
+EXTERN xcpt_t stm32_lm75attach(xcpt_t irqhandler);
+#endif
+
 #undef EXTERN
 #if defined(__cplusplus)
 }
diff --git a/nuttx/configs/stm3210e-eval/src/Makefile b/nuttx/configs/stm3210e-eval/src/Makefile
index 8dd072bdf..f4177d760 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/Makefile
+++ b/nuttx/configs/stm3210e-eval/src/Makefile
@@ -56,6 +56,10 @@ ifeq ($(CONFIG_USBSTRG),y)
 CSRCS		+= up_usbstrg.c
 endif
 
+ifeq ($(CONFIG_I2C_LM75),y)
+CSRCS		+= up_lm75.c
+endif
+
 COBJS		= $(CSRCS:.c=$(OBJEXT))
 
 SRCS		= $(ASRCS) $(CSRCS)
diff --git a/nuttx/configs/stm3210e-eval/src/README.txt b/nuttx/configs/stm3210e-eval/src/README.txt
index d4eda82fd..d4eda82fd 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/README.txt
+++ b/nuttx/configs/stm3210e-eval/src/README.txt
diff --git a/nuttx/configs/stm3210e-eval/src/stm3210e-internal.h b/nuttx/configs/stm3210e-eval/src/stm3210e-internal.h
index 42d3090e0..e86b9a66a 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/stm3210e-internal.h
+++ b/nuttx/configs/stm3210e-eval/src/stm3210e-internal.h
@@ -1,277 +1,282 @@
-/************************************************************************************

- * configs/stm3210e_eval/src/stm3210e_internal.h

- * arch/arm/src/board/stm3210e_internal.n

- *

- *   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 __CONFIGS_STM3210E_EVAL_SRC_STM3210E_INTERNAL_H

-#define __CONFIGS_STM3210E_EVAL_SRC_STM3210E_INTERNAL_H

-

-/************************************************************************************

- * Included Files

- ************************************************************************************/

-

-#include <nuttx/config.h>

-#include <nuttx/compiler.h>

-#include <stdint.h>

-

-/************************************************************************************

- * Definitions

- ************************************************************************************/

-

-/* How many SPI modules does this chip support? The LM3S6918 supports 2 SPI

- * modules (others may support more -- in such case, the following must be

- * expanded).

- */

-

-#if STM32_NSPI < 1

-#  undef CONFIG_STM32_SPI1

-#  undef CONFIG_STM32_SPI2

-#elif STM32_NSPI < 2

-#  undef CONFIG_STM32_SPI2

-#endif

-

-/* STM3210E-EVAL GPIOs **************************************************************/

-

-/* LEDs */

-

-#define GPIO_LED1       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\

-                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN6)

-#define GPIO_LED2       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\

-                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN7)

-#define GPIO_LED3       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\

-                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN8)

-#define GPIO_LED4       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\

-                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN9)

-

-/* BUTTONS -- NOTE that some have EXTI interrupts configured */

-

-#define MIN_IRQBUTTON   BUTTON_KEY

-#define MAX_IRQBUTTON   JOYSTICK_UP

-#define NUM_IRQBUTTONS  (JOYSTICK_UP - BUTTON_KEY + 1)

-

-#define GPIO_BTN_WAKEUP (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_PORTA|GPIO_PIN0)

-#define GPIO_BTN_TAMPER (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_PORTC|GPIO_PIN13)

-#define GPIO_BTN_KEY    (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN8)

-#define GPIO_JOY_SEL    (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN7)

-#define GPIO_JOY_DOWN   (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_EXTI|GPIO_PORTD|GPIO_PIN3)

-#define GPIO_JOY_LEFT   (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN14)

-#define GPIO_JOY_RIGHT  (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN13)

-#define GPIO_JOY_UP     (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\

-                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN15)

-

-/* SPI FLASH chip select:  PA.4 */

-

-#define GPIO_FLASH_CS   (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\

-                         GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN2)

-

-/* USB Soft Connect Pullup: PB.14 */

-

-#define GPIO_USB_PULLUP (GPIO_OUTPUT|GPIO_CNF_OUTOD|GPIO_MODE_50MHz|\

-                         GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN14)

-

-/************************************************************************************

- * Public Types

- ************************************************************************************/

-

-/* GPIO settings that will be altered when external memory is selected */

-

-struct extmem_save_s

-{

-  uint32_t gpiod_crl;

-  uint32_t gpiod_crh;

-  uint32_t gpioe_crl;

-  uint32_t gpioe_crh;

-  uint32_t gpiof_crl;

-  uint32_t gpiof_crh;

-  uint32_t gpiog_crl;

-  uint32_t gpiog_crh;

-};

-

-/************************************************************************************

- * Public data

- ************************************************************************************/

-

-#ifndef __ASSEMBLY__

-

-/* GPIO configurations common to SRAM and NOR Flash */

-

-#define NCOMMON_CONFIG 37

-extern const uint16_t g_commonconfig[NCOMMON_CONFIG];

-

-/************************************************************************************

- * Public Functions

- ************************************************************************************/

-

-/************************************************************************************

- * Name: stm32_spiinitialize

- *

- * Description:

- *   Called to configure SPI chip select GPIO pins for the STM3210E-EVAL board.

- *

- ************************************************************************************/

-

-extern void weak_function stm32_spiinitialize(void);

-

-/************************************************************************************

- * Name: stm32_usbinitialize

- *

- * Description:

- *   Called to setup USB-related GPIO pins for the STM3210E-EVAL board.

- *

- ************************************************************************************/

-

-extern void weak_function stm32_usbinitialize(void);

-

-/************************************************************************************

- * Name: stm32_extcontextsave

- *

- * Description:

- *  Save current GPIOs that will used by external memory configurations

- *

- ************************************************************************************/

-

-#ifdef CONFIG_STM32_FSMC

-extern void stm32_extcontextsave(struct extmem_save_s *save);

-

-/************************************************************************************

- * Name: stm32_extcontextrestore

- *

- * Description:

- *  Restore GPIOs that were used by external memory configurations

- *

- ************************************************************************************/

-

-extern void stm32_extcontextrestore(struct extmem_save_s *restore);

-

-/************************************************************************************

- * Name: stm32_extmemgpios

- *

- * Description:

- *   Initialize GPIOs for NOR or SRAM

- *

- ************************************************************************************/

-

-extern void stm32_extmemgpios(const uint16_t *gpios, int ngpios);

-

-/************************************************************************************

- * Name: stm32_enablefsmc

- *

- * Description:

- *  enable clocking to the FSMC module

- *

- ************************************************************************************/

-

-extern void stm32_enablefsmc(void);

-

-/************************************************************************************

- * Name: stm32_disablefsmc

- *

- * Description:

- *  enable clocking to the FSMC module

- *

- ************************************************************************************/

-

-extern void stm32_disablefsmc(void);

-

-/************************************************************************************

- * Name: stm32_selectnor

- *

- * Description:

- *   Initialize to access NOR flash

- *

- ************************************************************************************/

-

-extern void stm32_selectnor(void);

-

-/************************************************************************************

- * Name: stm32_deselectnor

- *

- * Description:

- *   Disable NOR FLASH

- *

- ************************************************************************************/

-

-extern void stm32_deselectnor(void);

-

-/************************************************************************************

- * Name: stm32_selectsram

- *

- * Description:

- *   Initialize to access external SRAM

- *

- ************************************************************************************/

-

-extern void stm32_selectsram(void);

-
/************************************************************************************

- * Name: stm32_deselectsram

- *

- * Description:

- *   Disable external SRAM

- *

- ************************************************************************************/

-

-extern void stm32_deselectsram(void);

-

-/************************************************************************************

- * Name: stm32_selectlcd

- *

- * Description:

- *   Initialize to the LCD

- *

- ************************************************************************************/

-

-extern void stm32_selectlcd(void);

-

-/************************************************************************************

- * Name: stm32_deselectlcd

- *

- * Description:

- *   Disable the LCD

- *

- ************************************************************************************/

-

-extern void stm32_deselectlcd(void);

-

-#endif /* CONFIG_STM32_FSMC */

-

-#endif /* __ASSEMBLY__ */

-#endif /* __CONFIGS_STM3210E_EVAL_SRC_STM3210E_INTERNAL_H */

-

+/************************************************************************************
+ * configs/stm3210e_eval/src/stm3210e_internal.h
+ * arch/arm/src/board/stm3210e_internal.n
+ *
+ *   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 __CONFIGS_STM3210E_EVAL_SRC_STM3210E_INTERNAL_H
+#define __CONFIGS_STM3210E_EVAL_SRC_STM3210E_INTERNAL_H
+
+/************************************************************************************
+ * Included Files
+ ************************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+#include <stdint.h>
+
+/************************************************************************************
+ * Definitions
+ ************************************************************************************/
+
+/* How many SPI modules does this chip support? The LM3S6918 supports 2 SPI
+ * modules (others may support more -- in such case, the following must be
+ * expanded).
+ */
+
+#if STM32_NSPI < 1
+#  undef CONFIG_STM32_SPI1
+#  undef CONFIG_STM32_SPI2
+#elif STM32_NSPI < 2
+#  undef CONFIG_STM32_SPI2
+#endif
+
+/* STM3210E-EVAL GPIOs **************************************************************/
+/* LEDs */
+
+#define GPIO_LED1       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\
+                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN6)
+#define GPIO_LED2       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\
+                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN7)
+#define GPIO_LED3       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\
+                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN8)
+#define GPIO_LED4       (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\
+                         GPIO_OUTPUT_CLEAR|GPIO_PORTF|GPIO_PIN9)
+
+/* BUTTONS -- NOTE that some have EXTI interrupts configured */
+
+#define MIN_IRQBUTTON   BUTTON_KEY
+#define MAX_IRQBUTTON   JOYSTICK_UP
+#define NUM_IRQBUTTONS  (JOYSTICK_UP - BUTTON_KEY + 1)
+
+#define GPIO_BTN_WAKEUP (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_PORTA|GPIO_PIN0)
+#define GPIO_BTN_TAMPER (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_PORTC|GPIO_PIN13)
+#define GPIO_BTN_KEY    (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN8)
+#define GPIO_JOY_SEL    (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN7)
+#define GPIO_JOY_DOWN   (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_EXTI|GPIO_PORTD|GPIO_PIN3)
+#define GPIO_JOY_LEFT   (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN14)
+#define GPIO_JOY_RIGHT  (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN13)
+#define GPIO_JOY_UP     (GPIO_INPUT|GPIO_CNF_INFLOAT|GPIO_MODE_INPUT|\
+                         GPIO_EXTI|GPIO_PORTG|GPIO_PIN15)
+
+/* SPI FLASH chip select:  PA.4 */
+
+#define GPIO_FLASH_CS   (GPIO_OUTPUT|GPIO_CNF_OUTPP|GPIO_MODE_50MHz|\
+                         GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN2)
+
+/* USB Soft Connect Pullup: PB.14 */
+
+#define GPIO_USB_PULLUP (GPIO_OUTPUT|GPIO_CNF_OUTOD|GPIO_MODE_50MHz|\
+                         GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN14)
+
+/* LM-75 Temperature Sensor: PB.5 */
+
+#define GPIO_LM75_OSINT (GPIO_INPUT|GPIO_CNF_INPULLUP|GPIO_MODE_10MHz|\
+                         GPIO_EXTI|GPIO_PORTB|GPIO_PIN5)
+
+/************************************************************************************
+ * Public Types
+ ************************************************************************************/
+
+/* GPIO settings that will be altered when external memory is selected */
+
+struct extmem_save_s
+{
+  uint32_t gpiod_crl;
+  uint32_t gpiod_crh;
+  uint32_t gpioe_crl;
+  uint32_t gpioe_crh;
+  uint32_t gpiof_crl;
+  uint32_t gpiof_crh;
+  uint32_t gpiog_crl;
+  uint32_t gpiog_crh;
+};
+
+/************************************************************************************
+ * Public data
+ ************************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+/* GPIO configurations common to SRAM and NOR Flash */
+
+#define NCOMMON_CONFIG 37
+extern const uint16_t g_commonconfig[NCOMMON_CONFIG];
+
+/************************************************************************************
+ * Public Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Name: stm32_spiinitialize
+ *
+ * Description:
+ *   Called to configure SPI chip select GPIO pins for the STM3210E-EVAL board.
+ *
+ ************************************************************************************/
+
+extern void weak_function stm32_spiinitialize(void);
+
+/************************************************************************************
+ * Name: stm32_usbinitialize
+ *
+ * Description:
+ *   Called to setup USB-related GPIO pins for the STM3210E-EVAL board.
+ *
+ ************************************************************************************/
+
+extern void weak_function stm32_usbinitialize(void);
+
+/************************************************************************************
+ * Name: stm32_extcontextsave
+ *
+ * Description:
+ *  Save current GPIOs that will used by external memory configurations
+ *
+ ************************************************************************************/
+
+#ifdef CONFIG_STM32_FSMC
+extern void stm32_extcontextsave(struct extmem_save_s *save);
+
+/************************************************************************************
+ * Name: stm32_extcontextrestore
+ *
+ * Description:
+ *  Restore GPIOs that were used by external memory configurations
+ *
+ ************************************************************************************/
+
+extern void stm32_extcontextrestore(struct extmem_save_s *restore);
+
+/************************************************************************************
+ * Name: stm32_extmemgpios
+ *
+ * Description:
+ *   Initialize GPIOs for NOR or SRAM
+ *
+ ************************************************************************************/
+
+extern void stm32_extmemgpios(const uint16_t *gpios, int ngpios);
+
+/************************************************************************************
+ * Name: stm32_enablefsmc
+ *
+ * Description:
+ *  enable clocking to the FSMC module
+ *
+ ************************************************************************************/
+
+extern void stm32_enablefsmc(void);
+
+/************************************************************************************
+ * Name: stm32_disablefsmc
+ *
+ * Description:
+ *  enable clocking to the FSMC module
+ *
+ ************************************************************************************/
+
+extern void stm32_disablefsmc(void);
+
+/************************************************************************************
+ * Name: stm32_selectnor
+ *
+ * Description:
+ *   Initialize to access NOR flash
+ *
+ ************************************************************************************/
+
+extern void stm32_selectnor(void);
+
+/************************************************************************************
+ * Name: stm32_deselectnor
+ *
+ * Description:
+ *   Disable NOR FLASH
+ *
+ ************************************************************************************/
+
+extern void stm32_deselectnor(void);
+
+/************************************************************************************
+ * Name: stm32_selectsram
+ *
+ * Description:
+ *   Initialize to access external SRAM
+ *
+ ************************************************************************************/
+
+extern void stm32_selectsram(void);
+
+/************************************************************************************
+ * Name: stm32_deselectsram
+ *
+ * Description:
+ *   Disable external SRAM
+ *
+ ************************************************************************************/
+
+extern void stm32_deselectsram(void);
+
+/************************************************************************************
+ * Name: stm32_selectlcd
+ *
+ * Description:
+ *   Initialize to the LCD
+ *
+ ************************************************************************************/
+
+extern void stm32_selectlcd(void);
+
+/************************************************************************************
+ * Name: stm32_deselectlcd
+ *
+ * Description:
+ *   Disable the LCD
+ *
+ ************************************************************************************/
+
+extern void stm32_deselectlcd(void);
+
+#endif /* CONFIG_STM32_FSMC */
+
+#endif /* __ASSEMBLY__ */
+#endif /* __CONFIGS_STM3210E_EVAL_SRC_STM3210E_INTERNAL_H */
+
diff --git a/nuttx/configs/stm3210e-eval/src/up_boot.c b/nuttx/configs/stm3210e-eval/src/up_boot.c
index 8646fee5b..8646fee5b 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/up_boot.c
+++ b/nuttx/configs/stm3210e-eval/src/up_boot.c
diff --git a/nuttx/configs/stm3210e-eval/src/up_lcd.c b/nuttx/configs/stm3210e-eval/src/up_lcd.c
index af4e412ce..af4e412ce 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/up_lcd.c
+++ b/nuttx/configs/stm3210e-eval/src/up_lcd.c
diff --git a/nuttx/configs/stm3210e-eval/src/up_leds.c b/nuttx/configs/stm3210e-eval/src/up_leds.c
index 611a5c849..611a5c849 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/up_leds.c
+++ b/nuttx/configs/stm3210e-eval/src/up_leds.c
diff --git a/nuttx/configs/stm3210e-eval/src/up_lm75.c b/nuttx/configs/stm3210e-eval/src/up_lm75.c
new file mode 100644
index 000000000..18107d947
--- /dev/null
+++ b/nuttx/configs/stm3210e-eval/src/up_lm75.c
@@ -0,0 +1,128 @@
+/************************************************************************************
+ * configs/stm3210e-eval/src/up_lm75.c
+ * arch/arm/src/board/up_lm75.c
+ *
+ *   Copyright (C) 2011 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.
+ *
+ ************************************************************************************/
+
+/************************************************************************************
+ * Included Files
+ ************************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <errno.h>
+
+#include <nuttx/i2c.h>
+#include <nuttx/sensors/lm75.h>
+
+#include "stm32.h"
+#include "stm32_i2c.h"
+#include "stm3210e-internal.h"
+
+#if defined(CONFIG_I2C) && defined(CONFIG_I2C_LM75) && defined(CONFIG_STM32_I2C1)
+
+/************************************************************************************
+ * Definitions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Private Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Public Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Name: stm32_lm75initialize
+ *
+ * Description:
+ *   Initialize and register the LM-75 Temperature Sensor driver.
+ *
+ * Input parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/temp0"
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ************************************************************************************/
+
+int stm32_lm75initialize(FAR const char *devpath)
+{
+  FAR struct i2c_dev_s *i2c;
+  int ret;
+
+  /* Configure PB.5 as Input pull-up.  This pin can be used as a temperature
+   * sensor interrupt (not fully implemented).
+   */
+
+  stm32_configgpio(GPIO_LM75_OSINT);
+
+  /* Get an instance of the I2C1 interface */
+
+  i2c =  up_i2cinitialize(1);
+  if (!i2c)
+    {
+      return -ENODEV;
+    }
+
+  /* Then register the temperature sensor */
+
+  ret = lm75_register(devpath, i2c, 0x48);
+  if (ret < 0)
+    {
+      (void)up_i2cuninitialize(i2c);
+    }
+  return ret;
+}
+
+/************************************************************************************
+ * Name: stm32_lm75attach
+ *
+ * Description:
+ *   Attach the LM-75 interrupt handler
+ *
+ * Input parameters:
+ *   irqhandler - the LM-75 interrupt handler
+ *
+ * Returned Value:
+ *   The previous LM-75 interrupt handler
+ *
+ ************************************************************************************/
+
+xcpt_t stm32_lm75attach(xcpt_t irqhandler)
+{
+  return stm32_gpiosetevent(GPIO_LM75_OSINT, true, true, true, irqhandler);
+}
+
+#endif /* CONFIG_I2C && CONFIG_I2C_LM75 && CONFIG_STM32_I2C1 */
diff --git a/nuttx/configs/stm3210e-eval/src/up_nsh.c b/nuttx/configs/stm3210e-eval/src/up_nsh.c
index 36430a52a..36430a52a 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/up_nsh.c
+++ b/nuttx/configs/stm3210e-eval/src/up_nsh.c
diff --git a/nuttx/configs/stm3210e-eval/src/up_spi.c b/nuttx/configs/stm3210e-eval/src/up_spi.c
index 3fc6567de..3fc6567de 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/up_spi.c
+++ b/nuttx/configs/stm3210e-eval/src/up_spi.c
diff --git a/nuttx/configs/stm3210e-eval/src/up_usbstrg.c b/nuttx/configs/stm3210e-eval/src/up_usbstrg.c
index f7ba205cc..f7ba205cc 100755..100644
--- a/nuttx/configs/stm3210e-eval/src/up_usbstrg.c
+++ b/nuttx/configs/stm3210e-eval/src/up_usbstrg.c
diff --git a/nuttx/drivers/sensors/Make.defs b/nuttx/drivers/sensors/Make.defs
index 1b3c3de03..bda3e8ed3 100644
--- a/nuttx/drivers/sensors/Make.defs
+++ b/nuttx/drivers/sensors/Make.defs
@@ -38,6 +38,10 @@
 
 ifeq ($(CONFIG_I2C),y)
   CSRCS += lis331dl.c
+
+ifeq ($(CONFIG_I2C_LM75),y)
+  CSRCS += lm75.c
+endif
 endif
 
 # Include sensor driver build support
diff --git a/nuttx/drivers/sensors/lm75.c b/nuttx/drivers/sensors/lm75.c
new file mode 100644
index 000000000..600f9aab3
--- /dev/null
+++ b/nuttx/drivers/sensors/lm75.c
@@ -0,0 +1,473 @@
+/****************************************************************************
+ * drivers/sensors/lm75.c
+ * Character driver for the STMicro LM-75 Temperature Sensor
+ *
+ *   Copyright (C) 2011 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+#include <fixedmath.h>
+#include <errno.h>
+
+#include <nuttx/fs.h>
+#include <nuttx/i2c.h>
+#include <nuttx/sensors/lm75.h>
+
+#if defined(CONFIG_I2C) && defined(CONFIG_I2C_LM75)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Centigrade to Fahrenheit conversion:  F = 9*C/5 + 32 */
+
+#define B16_9DIV5  (9 * 65536 / 5)
+#define B16_32     (32 * 65536);
+
+/****************************************************************************
+ * Private
+ ****************************************************************************/
+
+struct lm75_dev_s
+{
+  FAR struct i2c_dev_s *i2c; /* I2C interface */
+  uint8_t addr;              /* I2C address */
+  bool fahrenheit;           /* true: temperature will be reported in fahrenheit */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+/* I2C Helpers */
+
+static int lm75_readb8(FAR struct lm75_dev_s *priv, uint8_t regaddr,
+                       FAR b8_t *regvalue);
+#if 0 // Not used
+static int lm75_writeb8(FAR struct lm75_dev_s *priv, uint8_t regaddr,
+                        b8_t regval);
+#endif
+static int lm75_readtemp(FAR struct lm75_dev_s *priv, b16_t *temp);
+static int lm75_readconf(FAR struct lm75_dev_s *priv, uint8_t *conf);
+static int lm75_writeconf(FAR struct lm75_dev_s *priv, uint8_t conf);
+
+/* Character driver methods */
+
+static int     lm75_open(FAR struct file *filep);
+static int     lm75_close(FAR struct file *filep);
+static ssize_t lm75_read(FAR struct file *, FAR char *, size_t);
+static ssize_t lm75_write(FAR struct file *filep, FAR const char *buffer, size_t buflen);
+static int     lm75_ioctl(FAR struct file *filep,int cmd,unsigned long arg);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct file_operations lm75_fops =
+{
+  lm75_open,
+  lm75_close,
+  lm75_read,
+  lm75_write,
+  0,
+  lm75_ioctl
+#ifndef CONFIG_DISABLE_POLL
+  , 0
+#endif
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+/****************************************************************************
+ * Name: lm75_readb8
+ *
+ * Description:
+ *   Read a 16-bit register (LM75_TEMP_REG, LM75_THYS_REG, or LM75_TOS_REG)
+ *
+ ****************************************************************************/
+
+static int lm75_readb8(FAR struct lm75_dev_s *priv, uint8_t regaddr,
+                       FAR b8_t *regvalue)
+{
+  uint8_t buffer[2];
+  int ret;
+
+  /* Write the register address */
+
+  I2C_SETADDRESS(priv->i2c, priv->addr, 7);
+  ret = I2C_WRITE(priv->i2c, &regaddr, 1);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Restart and read 16-bits from the register (discarding 7) */
+
+  ret = I2C_READ(priv->i2c, buffer, 2);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Data format is:  TTTTTTTT Txxxxxxx where TTTTTTTTT is a nine-bit
+   * temperature value with LSB = 0.5 degrees centigrade.  So the raw
+   * data is b8_t
+   */
+
+  *regvalue = (b8_t)buffer[0] << 8 | (b8_t)buffer[1];
+  return OK;
+}
+
+/****************************************************************************
+ * Name: lm75_writeb8
+ *
+ * Description:
+ *   Write to a 16-bit register (LM75_TEMP_REG, LM75_THYS_REG, or LM75_TOS_REG)
+ *
+ ****************************************************************************/
+#if 0 // Not used
+static int lm75_writeb8(FAR struct lm75_dev_s *priv, uint8_t regaddr,
+                        b8_t regval)
+{
+  uint8_t buffer[3];
+
+  /* Set up a 3 byte message to send */
+
+  buffer[0] = regaddr;
+  buffer[1] = regval >> 8;
+  buffer[2] = regval;
+
+  /* Write the register address followed by the data (no RESTART) */
+
+  I2C_SETADDRESS(priv->i2c, priv->addr, 7);
+  return I2C_WRITE(priv->i2c, buffer, 3);
+}
+#endif
+
+/****************************************************************************
+ * Name: lm75_readtemp
+ *
+ * Description:
+ *   Read the temperature register with special scaling (LM75_TEMP_REG)
+ *
+ ****************************************************************************/
+
+static int lm75_readtemp(FAR struct lm75_dev_s *priv, b16_t *temp)
+{
+  b8_t  temp8;
+  b16_t temp16;
+  int ret;
+
+  /* Read the raw temperature data.  Data format is:  TTTTTTTT Txxxxxxx where
+   * TTTTTTTTT is a nine-bit temperature value with LSB = 0.5 degrees centigrade. 
+   * So the raw data is b8_t.
+   */
+  
+  ret = lm75_readb8(priv, LM75_TEMP_REG, &temp8);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Convert to b16_t */
+
+  temp16 = b8tob16(temp8);
+
+  /* Was fahrenheit requested? */
+
+  if (priv->fahrenheit)
+    {
+      /* Centigrade to Fahrenheit conversion:  F = 9*C/5 + 32 */
+
+      temp16 =  b16mulb16(temp16, B16_9DIV5) + B16_32;
+    }
+
+  *temp = temp16;
+  return OK;
+}
+
+/****************************************************************************
+ * Name: lm75_readconf
+ *
+ * Description:
+ *   Read the 8-bit LM75 configuration register
+ *
+ ****************************************************************************/
+
+static int lm75_readconf(FAR struct lm75_dev_s *priv, uint8_t *conf)
+{
+  uint8_t buffer;
+  int ret;
+
+  /* Write the configuration register address */
+
+  I2C_SETADDRESS(priv->i2c, priv->addr, 7);
+
+  buffer = LM75_CONF_REG;
+  ret = I2C_WRITE(priv->i2c, &buffer, 1);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Restart and read 8-bits from the register */
+
+  ret = I2C_READ(priv->i2c, conf, 1);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: lm75_writeconf
+ *
+ * Description:
+ *   Write to a 8-bit LM75 configuration register.
+ *
+ ****************************************************************************/
+
+static int lm75_writeconf(FAR struct lm75_dev_s *priv, uint8_t conf)
+{
+  uint8_t buffer[2];
+
+  /* Set up a 2 byte message to send */
+
+  buffer[0] = LM75_CONF_REG;
+  buffer[1] = conf;
+
+  /* Write the register address followed by the data (no RESTART) */
+
+  I2C_SETADDRESS(priv->i2c, priv->addr, 7);
+  return I2C_WRITE(priv->i2c, buffer, 2);
+}
+
+/****************************************************************************
+ * Name: lm75_open
+ *
+ * Description:
+ *   This function is called whenever the LM-75 device is opened.
+ *
+ ****************************************************************************/
+
+static int lm75_open(FAR struct file *filep)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: lm75_close
+ *
+ * Description:
+ *   This routine is called when the LM-75 device is closed.
+ *
+ ****************************************************************************/
+
+static int lm75_close(FAR struct file *filep)
+{
+  return OK;
+}
+
+/****************************************************************************
+ * Name: lm75_read
+ ****************************************************************************/
+
+static ssize_t lm75_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
+{
+  FAR struct inode      *inode = filep->f_inode;
+  FAR struct lm75_dev_s *priv   = inode->i_private;
+  FAR b16_t             *ptr;
+  ssize_t                nsamples;
+  int                    ret;
+
+  /* How many samples were requested to get? */
+
+  nsamples = buflen/sizeof(b16_t);
+  ptr      = (FAR b16_t *)buffer;
+
+  /* Get the requested number of samples */
+
+  for (; nsamples > 0; nsamples--)
+    {
+      b16_t temp;
+
+      /* Read the next b16_t temperature value */
+
+      ret = lm75_readtemp(priv, &temp);
+      if (ret < 0)
+        {
+          return (ssize_t)ret;
+        }
+
+      /* Save the temperature value in the user buffer */
+
+      *ptr++ = temp;
+    }
+
+  return nsamples * sizeof(b16_t);
+}
+
+/****************************************************************************
+ * Name: lm75_write
+ ****************************************************************************/
+
+static ssize_t lm75_write(FAR struct file *filep, FAR const char *buffer,
+                          size_t buflen)
+{
+  return -ENOSYS;
+}
+
+/****************************************************************************
+ * Name: lm75_ioctl
+ ****************************************************************************/
+
+static int lm75_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
+{
+  FAR struct inode      *inode = filep->f_inode;
+  FAR struct lm75_dev_s *priv  = inode->i_private;
+  int                    ret   = OK;
+
+  switch (arg)
+    {
+      /* Read from the configuration register. Arg: uint8_t* pointer */
+
+      case SNIOC_READCONF:
+        {
+          FAR uint8_t *ptr = (FAR uint8_t *)((uintptr_t)arg);
+          ret = lm75_readconf(priv, ptr);
+        }
+        break;
+
+      /* Wrtie to the configuration register. Arg:  uint8_t value */
+
+      case SNIOC_WRITECONF:
+        ret = lm75_writeconf(priv, (uint8_t)arg);
+        break;
+
+      /* Shutdown the LM75, Arg: None */
+
+      case SNIOC_SHUTDOWN:
+        {
+          uint8_t conf;
+          ret = lm75_readconf(priv, &conf);
+          if (ret == OK)
+            {
+              ret = lm75_writeconf(priv, conf | LM75_CONF_SHUTDOWN);
+            }
+        }
+        break;
+
+      /* Powerup the LM75, Arg: None */
+
+      case SNIOC_POWERUP:
+        {
+          uint8_t conf;
+          ret = lm75_readconf(priv, &conf);
+          if (ret == OK)
+            {
+              ret = lm75_writeconf(priv, conf & ~LM75_CONF_SHUTDOWN);
+            }
+        }
+        break;
+
+      /* Report samples in Fahrenheit */
+
+      case SNIOC_FAHRENHEIT:
+        priv->fahrenheit = true;
+        break;
+
+      /* Report Samples in Centigrade */
+
+      case SNIOC_CENTIGRADE:
+        priv->fahrenheit = false;
+        break;
+
+      default:
+        ret = -ENOTTY;
+        break;
+    }
+
+  return ret;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lm75_register
+ *
+ * Description:
+ *   Register the LM-75 character device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/temp0"
+ *   i2c - An instance of the I2C interface to use to communicate with LM75
+ *   addr - The I2C address of the LM-75.  The base I2C address of the LM75
+ *   is 0x48.  Bits 0-3 can be controlled to get 8 unique addresses from 0x48
+ *   through 0x4f.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+int lm75_register(FAR const char *devpath, FAR struct i2c_dev_s *i2c, uint8_t addr)
+{
+  FAR struct lm75_dev_s *priv;
+  int ret;
+
+  /* Initialize the LM-75 device structure */
+
+  priv = (FAR struct lm75_dev_s *)malloc(sizeof(struct lm75_dev_s));
+  if (!priv)
+    {
+      return -ENOMEM;
+    }
+
+  priv->i2c        = i2c;
+  priv->addr       = addr;
+  priv->fahrenheit = false;
+
+  /* Register the character driver */
+
+  ret = register_driver(devpath, &lm75_fops, 0555, priv);
+  if (ret < 0)
+    {
+      free(priv);
+    }
+  return ret;
+}
+#endif /* CONFIG_I2C && CONFIG_I2C_LM75 */
diff --git a/nuttx/include/nuttx/ioctl.h b/nuttx/include/nuttx/ioctl.h
index 0ce363f24..194b83715 100644
--- a/nuttx/include/nuttx/ioctl.h
+++ b/nuttx/include/nuttx/ioctl.h
@@ -60,6 +60,7 @@
 #define _SIOCBASE       (0x8b00) /* Socket ioctl commands */
 #define _ARPBASE        (0x8c00) /* ARP ioctl commands */
 #define _TSBASE         (0x8d00) /* Touchscreen ioctl commands */
+#define _SNBASE         (0x8e00) /* Sensor ioctl commands */
 
 /* Macros used to manage ioctl commands */
 
@@ -161,11 +162,16 @@
 #define _ARPIOCVALID(c)   (_IOC_TYPE(c)==_ARPBASE)
 #define _ARPIOC(nr)       _IOC(_ARPBASE,nr)
 
-/* NuttX ARP touchscrren ioctl definitions (see nuttx/input/touchscreen.h) **/
+/* NuttX ARP touchscreen ioctl definitions (see nuttx/input/touchscreen.h) **/
 
 #define _TSIOCVALID(c)    (_IOC_TYPE(c)==_TSBASE)
 #define _TSIOC(nr)        _IOC(_TSBASE,nr)
 
+/* NuttX ARP sensor ioctl definitions (see nuttx/sensor/*.h) ****************/
+
+#define _SNIOCVALID(c)    (_IOC_TYPE(c)==_SNBASE)
+#define _SNIOC(nr)        _IOC(_SNBASE,nr)
+
 /****************************************************************************
  * Public Type Definitions
  ****************************************************************************/
diff --git a/nuttx/include/nuttx/sensors/lm75.h b/nuttx/include/nuttx/sensors/lm75.h
new file mode 100644
index 000000000..54100088e
--- /dev/null
+++ b/nuttx/include/nuttx/sensors/lm75.h
@@ -0,0 +1,129 @@
+/****************************************************************************
+ * include/nuttx/lm75.h
+ *
+ *   Copyright (C) 2011 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_SENSORSD_LM75_H
+#define __NUTTX_SENSORSD_LM75_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/ioctl.h>
+
+/****************************************************************************
+ * Pre-Processor Definitions
+ ****************************************************************************/
+/* Configuration ************************************************************
+ * CONFIG_I2C - Enables support for I2C drivers
+ * CONFIG_I2C_LM75 - Enables support for the LM-75 driver
+ */
+
+#define CONFIG_LM75_BASEADDR 0x48
+
+/* IOCTL Commands ***********************************************************/
+
+#define SNIOC_READCONF     _SNIOC(0x0001) /* Arg: uint8_t* pointer */
+#define SNIOC_WRITECONF    _SNIOC(0x0002) /* Arg: uint8_t value */
+#define SNIOC_SHUTDOWN     _SNIOC(0x0003) /* Arg: None */
+#define SNIOC_POWERUP      _SNIOC(0x0004) /* Arg: None */
+#define SNIOC_FAHRENHEIT   _SNIOC(0x0005) /* Arg: None */
+#define SNIOC_CENTIGRADE   _SNIOC(0x0006) /* Arg: None */
+
+/* LM-75 Register Definitions ***********************************************/
+/* LM-75 Registers addresses */
+
+#define LM75_TEMP_REG      0x00     /* Temperature Register */
+#define LM75_CONF_REG      0x01     /* Configuration Register */
+#define LM75_THYS_REG      0x02     /* Temperature Register */
+#define LM75_TOS_REG       0x03     /* Over-temp Shutdown threshold Register */
+
+/* Configuration Register Bit Definitions */
+
+#define LM75_CONF_SHUTDOWN (1 << 0) /* Bit 0: Put LM75 goes in low power shutdown mode */
+#define LM75_CONF_INTMODE  (1 << 1) /* Bit 1: 0=Comparator 1=Interrupt mode */
+#define LM75_CONF_POLARITY (1 << 2) /* Bit 2: 0=O.S. Active low 1=active high */
+#define LM75_CONF_FAULTQ   (3)      /* Bits 3-4: # faults before setting O.S. */
+
+/* NOTE: When temperature values are read, they are return as b16_t, fixed
+ * precision integer values (see include/fixedmath.h).
+ */
+
+/****************************************************************************
+ * Global Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Function Prototypes
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Name: lm75_register
+ *
+ * Description:
+ *   Register the LM-75 character device as 'devpath'
+ *
+ * Input Parameters:
+ *   devpath - The full path to the driver to register. E.g., "/dev/temp0"
+ *   i2c - An instance of the I2C interface to use to communicate with LM75
+ *   addr - The I2C address of the LM-75.  The base I2C address of the LM75
+ *   is 0x48.  Bits 0-3 can be controlled to get 8 unique addresses from 0x48
+ *   through 0x4f.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+EXTERN int lm75_register(FAR const char *devpath, FAR struct i2c_dev_s *i2c,
+                         uint8_t addr);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __NUTTX_SENSORSD_LM75_H */