forked from Archive/PX4-Autopilot
538 lines
15 KiB
C
538 lines
15 KiB
C
/****************************************************************************
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* drivers/sensors/lm75.c
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* Character driver for the STMicro LM-75 Temperature Sensor
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*
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* Copyright (C) 2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdlib.h>
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#include <fixedmath.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/i2c.h>
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#include <nuttx/sensors/lm75.h>
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#if defined(CONFIG_I2C) && defined(CONFIG_I2C_LM75)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Centigrade to Fahrenheit conversion: F = 9*C/5 + 32 */
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#define B16_9DIV5 (9 * 65536 / 5)
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#define B16_32 (32 * 65536)
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/* Debug for this file only */
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#ifdef CONFIG_DEBUG_LM75
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# define lm75dbg dbg
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#else
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# ifdef CONFIG_CPP_HAVE_VARARGS
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# define lm75dbg(x...)
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# else
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# define lm75dbg (void)
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# endif
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#endif
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/****************************************************************************
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* Private
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****************************************************************************/
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struct lm75_dev_s
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{
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FAR struct i2c_dev_s *i2c; /* I2C interface */
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uint8_t addr; /* I2C address */
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bool fahrenheit; /* true: temperature will be reported in fahrenheit */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/* I2C Helpers */
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static int lm75_readb16(FAR struct lm75_dev_s *priv, uint8_t regaddr,
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FAR b16_t *regvalue);
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static int lm75_writeb16(FAR struct lm75_dev_s *priv, uint8_t regaddr,
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b16_t regval);
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static int lm75_readtemp(FAR struct lm75_dev_s *priv, FAR b16_t *temp);
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static int lm75_readconf(FAR struct lm75_dev_s *priv, FAR uint8_t *conf);
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static int lm75_writeconf(FAR struct lm75_dev_s *priv, uint8_t conf);
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/* Character driver methods */
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static int lm75_open(FAR struct file *filep);
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static int lm75_close(FAR struct file *filep);
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static ssize_t lm75_read(FAR struct file *, FAR char *, size_t);
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static ssize_t lm75_write(FAR struct file *filep, FAR const char *buffer, size_t buflen);
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static int lm75_ioctl(FAR struct file *filep,int cmd,unsigned long arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations lm75_fops =
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{
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lm75_open,
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lm75_close,
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lm75_read,
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lm75_write,
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0,
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lm75_ioctl
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#ifndef CONFIG_DISABLE_POLL
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, 0
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#endif
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: lm75_readb16
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*
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* Description:
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* Read a 16-bit register (LM75_TEMP_REG, LM75_THYS_REG, or LM75_TOS_REG)
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*
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****************************************************************************/
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static int lm75_readb16(FAR struct lm75_dev_s *priv, uint8_t regaddr,
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FAR b16_t *regvalue)
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{
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uint8_t buffer[2];
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int ret;
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/* Write the register address */
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I2C_SETADDRESS(priv->i2c, priv->addr, 7);
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ret = I2C_WRITE(priv->i2c, ®addr, 1);
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if (ret < 0)
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{
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lm75dbg("I2C_WRITE failed: %d\n", ret);
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return ret;
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}
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/* Restart and read 16-bits from the register (discarding 7) */
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ret = I2C_READ(priv->i2c, buffer, 2);
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if (ret < 0)
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{
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lm75dbg("I2C_READ failed: %d\n", ret);
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return ret;
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}
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/* Data format is: TTTTTTTT Txxxxxxx where TTTTTTTTT is a nine-bit,
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* signed temperature value with LSB = 0.5 degrees centigrade. So the
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* raw data is b8_t
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*/
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*regvalue = b8tob16((b8_t)buffer[0] << 8 | (b8_t)buffer[1]);
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lm75dbg("addr: %02x value: %08x ret: %d\n", regaddr, *regvalue, ret);
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return OK;
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}
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/****************************************************************************
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* Name: lm75_writeb16
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*
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* Description:
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* Write to a 16-bit register (LM75_TEMP_REG, LM75_THYS_REG, or LM75_TOS_REG)
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*
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****************************************************************************/
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static int lm75_writeb16(FAR struct lm75_dev_s *priv, uint8_t regaddr,
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b16_t regval)
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{
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uint8_t buffer[3];
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b8_t regb8;
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lm75dbg("addr: %02x value: %08x\n", regaddr, regval);
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/* Set up a 3 byte message to send */
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buffer[0] = regaddr;
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regb8 = b16tob8(regval);
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buffer[1] = (uint8_t)(regb8 >> 8);
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buffer[2] = (uint8_t)regb8;
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/* Write the register address followed by the data (no RESTART) */
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I2C_SETADDRESS(priv->i2c, priv->addr, 7);
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return I2C_WRITE(priv->i2c, buffer, 3);
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}
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/****************************************************************************
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* Name: lm75_readtemp
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*
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* Description:
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* Read the temperature register with special scaling (LM75_TEMP_REG)
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*
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****************************************************************************/
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static int lm75_readtemp(FAR struct lm75_dev_s *priv, FAR b16_t *temp)
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{
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b16_t temp16;
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int ret;
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/* Read the raw temperature data (b16_t) */
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ret = lm75_readb16(priv, LM75_TEMP_REG, &temp16);
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if (ret < 0)
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{
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lm75dbg("lm75_readb16 failed: %d\n", ret);
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return ret;
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}
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lm75dbg("Centigrade: %08x\n", temp16);
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/* Was fahrenheit requested? */
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if (priv->fahrenheit)
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{
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/* Centigrade to Fahrenheit conversion: F = 9*C/5 + 32 */
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temp16 = b16mulb16(temp16, B16_9DIV5) + B16_32;
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lm75dbg("Fahrenheit: %08x\n", temp16);
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}
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*temp = temp16;
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return OK;
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}
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/****************************************************************************
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* Name: lm75_readconf
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*
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* Description:
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* Read the 8-bit LM75 configuration register
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*
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****************************************************************************/
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static int lm75_readconf(FAR struct lm75_dev_s *priv, FAR uint8_t *conf)
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{
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uint8_t buffer;
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int ret;
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/* Write the configuration register address */
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I2C_SETADDRESS(priv->i2c, priv->addr, 7);
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buffer = LM75_CONF_REG;
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ret = I2C_WRITE(priv->i2c, &buffer, 1);
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if (ret < 0)
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{
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lm75dbg("I2C_WRITE failed: %d\n", ret);
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return ret;
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}
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/* Restart and read 8-bits from the register */
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ret = I2C_READ(priv->i2c, conf, 1);
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lm75dbg("conf: %02x ret: %d\n", *conf, ret);
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return ret;
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}
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/****************************************************************************
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* Name: lm75_writeconf
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*
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* Description:
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* Write to a 8-bit LM75 configuration register.
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*
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****************************************************************************/
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static int lm75_writeconf(FAR struct lm75_dev_s *priv, uint8_t conf)
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{
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uint8_t buffer[2];
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lm75dbg("conf: %02x\n", conf);
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/* Set up a 2 byte message to send */
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buffer[0] = LM75_CONF_REG;
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buffer[1] = conf;
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/* Write the register address followed by the data (no RESTART) */
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I2C_SETADDRESS(priv->i2c, priv->addr, 7);
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return I2C_WRITE(priv->i2c, buffer, 2);
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}
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/****************************************************************************
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* Name: lm75_open
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*
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* Description:
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* This function is called whenever the LM-75 device is opened.
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*
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****************************************************************************/
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static int lm75_open(FAR struct file *filep)
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{
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return OK;
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}
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/****************************************************************************
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* Name: lm75_close
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*
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* Description:
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* This routine is called when the LM-75 device is closed.
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*
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****************************************************************************/
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static int lm75_close(FAR struct file *filep)
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{
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return OK;
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}
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/****************************************************************************
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* Name: lm75_read
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****************************************************************************/
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static ssize_t lm75_read(FAR struct file *filep, FAR char *buffer, size_t buflen)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct lm75_dev_s *priv = inode->i_private;
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FAR b16_t *ptr;
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ssize_t nsamples;
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int i;
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int ret;
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/* How many samples were requested to get? */
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nsamples = buflen / sizeof(b16_t);
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ptr = (FAR b16_t *)buffer;
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lm75dbg("buflen: %d nsamples: %d\n", buflen, nsamples);
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/* Get the requested number of samples */
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for (i = 0; i < nsamples; i++)
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{
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b16_t temp;
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/* Read the next b16_t temperature value */
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ret = lm75_readtemp(priv, &temp);
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if (ret < 0)
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{
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lm75dbg("lm75_readtemp failed: %d\n",ret);
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return (ssize_t)ret;
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}
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/* Save the temperature value in the user buffer */
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*ptr++ = temp;
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}
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return nsamples * sizeof(b16_t);
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}
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/****************************************************************************
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* Name: lm75_write
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****************************************************************************/
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static ssize_t lm75_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen)
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{
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return -ENOSYS;
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}
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/****************************************************************************
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* Name: lm75_ioctl
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****************************************************************************/
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static int lm75_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
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{
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FAR struct inode *inode = filep->f_inode;
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FAR struct lm75_dev_s *priv = inode->i_private;
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int ret = OK;
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switch (cmd)
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{
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/* Read from the configuration register. Arg: uint8_t* pointer */
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case SNIOC_READCONF:
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{
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FAR uint8_t *ptr = (FAR uint8_t *)((uintptr_t)arg);
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ret = lm75_readconf(priv, ptr);
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lm75dbg("conf: %02x ret: %d\n", *ptr, ret);
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}
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break;
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/* Wrtie to the configuration register. Arg: uint8_t value */
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case SNIOC_WRITECONF:
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ret = lm75_writeconf(priv, (uint8_t)arg);
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lm75dbg("conf: %02x ret: %d\n", *(uint8_t*)arg, ret);
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break;
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/* Shutdown the LM75, Arg: None */
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case SNIOC_SHUTDOWN:
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{
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uint8_t conf;
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ret = lm75_readconf(priv, &conf);
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if (ret == OK)
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{
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ret = lm75_writeconf(priv, conf | LM75_CONF_SHUTDOWN);
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}
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lm75dbg("conf: %02x ret: %d\n", conf | LM75_CONF_SHUTDOWN, ret);
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}
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break;
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/* Powerup the LM75, Arg: None */
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case SNIOC_POWERUP:
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{
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uint8_t conf;
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ret = lm75_readconf(priv, &conf);
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if (ret == OK)
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{
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ret = lm75_writeconf(priv, conf & ~LM75_CONF_SHUTDOWN);
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}
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lm75dbg("conf: %02x ret: %d\n", conf & ~LM75_CONF_SHUTDOWN, ret);
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}
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break;
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/* Report samples in Fahrenheit */
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case SNIOC_FAHRENHEIT:
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priv->fahrenheit = true;
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lm75dbg("Fahrenheit\n");
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break;
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/* Report Samples in Centigrade */
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case SNIOC_CENTIGRADE:
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priv->fahrenheit = false;
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lm75dbg("Centigrade\n");
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break;
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/* Read THYS temperature register. Arg: b16_t* pointer */
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case SNIOC_READTHYS:
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{
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FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg);
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ret = lm75_readb16(priv, LM75_THYS_REG, ptr);
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lm75dbg("THYS: %08x ret: %d\n", *ptr, ret);
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}
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break;
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/* Write THYS temperature register. Arg: b16_t value */
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case SNIOC_WRITETHYS:
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ret = lm75_writeb16(priv, LM75_THYS_REG, (b16_t)arg);
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lm75dbg("THYS: %08x ret: %d\n", (b16_t)arg, ret);
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break;
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/* Read TOS (Over-temp Shutdown Threshold) Register. Arg: b16_t* pointer */
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case SNIOC_READTOS:
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{
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FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg);
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ret = lm75_readb16(priv, LM75_TOS_REG, ptr);
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lm75dbg("TOS: %08x ret: %d\n", *ptr, ret);
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}
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break;
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/* Write TOS (Over-temp Shutdown Threshold) Register. Arg: b16_t value */
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case SNIOC_WRITRETOS:
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ret = lm75_writeb16(priv, LM75_TOS_REG, (b16_t)arg);
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lm75dbg("TOS: %08x ret: %d\n", (b16_t)arg, ret);
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break;
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default:
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lm75dbg("Unrecognized cmd: %d\n", cmd);
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ret = -ENOTTY;
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break;
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}
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: lm75_register
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*
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* Description:
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* Register the LM-75 character device as 'devpath'
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*
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* Input Parameters:
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* devpath - The full path to the driver to register. E.g., "/dev/temp0"
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* i2c - An instance of the I2C interface to use to communicate with LM75
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* addr - The I2C address of the LM-75. The base I2C address of the LM75
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* is 0x48. Bits 0-3 can be controlled to get 8 unique addresses from 0x48
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* through 0x4f.
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*
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* Returned Value:
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* Zero (OK) on success; a negated errno value on failure.
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*
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****************************************************************************/
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int lm75_register(FAR const char *devpath, FAR struct i2c_dev_s *i2c, uint8_t addr)
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{
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FAR struct lm75_dev_s *priv;
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int ret;
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/* Initialize the LM-75 device structure */
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priv = (FAR struct lm75_dev_s *)malloc(sizeof(struct lm75_dev_s));
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if (!priv)
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{
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lm75dbg("Failed to allocate instance\n");
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return -ENOMEM;
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}
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priv->i2c = i2c;
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priv->addr = addr;
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priv->fahrenheit = false;
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/* Register the character driver */
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ret = register_driver(devpath, &lm75_fops, 0555, priv);
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if (ret < 0)
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{
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lm75dbg("Failed to register driver: %d\n", ret);
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free(priv);
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}
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return ret;
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}
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#endif /* CONFIG_I2C && CONFIG_I2C_LM75 */
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