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

2 files changed, 477 insertions, 0 deletions

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 */