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drivers/sensors/mcp9844: Driver for the MCP9844 I2C digital temperature sensor with a selectable resolution

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This commit is contained in:
Alexander Entinger 2016-01-15 07:25:58 -06:00 committed by Gregory Nutt
parent 2a5c7e9a92
commit 75d6c4cee3
5 changed files with 494 additions and 0 deletions
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3
ChangeLog
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@ -11305,3 +11305,6 @@
(2016-01-10).
* libc/netdb: Add support for the use of a DNS resolver file like
/etc/resolv.conf (2016-01-14).
* drivers/sensors/mcp9844.c and include/nuttx/sensors/mcp9844.h: Driver
for the MCP9844 I2C digital temperature sensor with a selectable
resolution. From Entinger Alexander (2016-01-15).

7
drivers/sensors/Kconfig
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@ -31,6 +31,13 @@ config MB7040
---help---
Enable driver support for the MaxBotix MB7040 sonar.
config MCP9844
bool "MCP9844 Temperature Sensor"
default n
select I2C
---help---
Enable driver support for the MCP9844 I2C Temperature sensor.
config MS58XX
bool "MEAS MS58XX Altimeter support"
default n

4
drivers/sensors/Make.defs
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@ -73,6 +73,10 @@ ifeq ($(CONFIG_MB7040),y)
CSRCS += mb7040.c
endif
ifeq ($(CONFIG_MCP9844),y)
CSRCS += mcp9844.c
endif
ifeq ($(CONFIG_MS58XX),y)
CSRCS += ms58xx.c
endif

352
drivers/sensors/mcp9844.c Normal file
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@ -0,0 +1,352 @@
/****************************************************************************
* drivers/sensors/mcp9844.c
* Character driver for the MCP9844 Temperature Sensor
*
* Copyright (C) 2015 DS-Automotion GmbH. All rights reserved.
* Author: Alexander Entinger <a.entinger@ds-automotion.com>
*
* 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 <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/i2c.h>
#include <nuttx/sensors/mcp9844.h>
#if defined(CONFIG_I2C) && defined(CONFIG_MCP9844)
/****************************************************************************
* Private
****************************************************************************/
struct mcp9844_dev_s
{
FAR struct i2c_dev_s *i2c; /* I2C interface */
uint8_t addr; /* I2C address */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* I2C helper functions */
static int mcp9844_read_u16(FAR struct mcp9844_dev_s *priv,
uint8_t const regaddr, FAR uint16_t *value);
static int mcp9844_write_u16(FAR struct mcp9844_dev_s *priv,
uint8_t const regaddr, uint16_t const regval);
/* Character driver methods */
static int mcp9844_open(FAR struct file *filep);
static int mcp9844_close(FAR struct file *filep);
static ssize_t mcp9844_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t mcp9844_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int mcp9844_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_mcp9844_fops =
{
mcp9844_open,
mcp9844_close,
mcp9844_read,
mcp9844_write,
NULL,
mcp9844_ioctl
#ifndef CONFIG_DISABLE_POLL
, NULL
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mcp9844_read_u16
*
* Description:
* Read a 16 bit valie from the MCP9844 at the address regaddr.
*
****************************************************************************/
static int mcp9844_read_u16(FAR struct mcp9844_dev_s *priv,
uint8_t const regaddr, FAR uint16_t *value)
{
int ret = -1;
/* Write the register address */
I2C_SETADDRESS(priv->i2c, priv->addr, 7);
ret = I2C_WRITE(priv->i2c, &regaddr, 1);
if (ret < 0)
{
sndbg ("I2C_WRITE failed: %d\n", ret);
return ret;
}
/* Restart and read 16-bits from the register */
uint8_t const BUFFER_SIZE = 2;
uint8_t buffer[BUFFER_SIZE];
ret = I2C_READ(priv->i2c, buffer, BUFFER_SIZE);
if (ret < 0)
{
sndbg ("I2C_READ failed: %d\n", ret);
return ret;
}
/* Copy the content of the buffer to the location of the uint16_t pointer */
*value = (((uint16_t)(buffer[0]))<<8) + ((uint16_t)(buffer[1]));
sndbg("addr: %02x value: %08x ret: %d\n", regaddr, *value, ret);
return OK;
}
/****************************************************************************
* Name: mcp9844_write_u16
*
* Description:
* Write to a 16-bit register of the MCP9844.
*
****************************************************************************/
static int mcp9844_write_u16(FAR struct mcp9844_dev_s *priv,
uint8_t const regaddr, uint16_t const regval)
{
sndbg("addr: %02x value: %08x\n", regaddr, regval);
/* Set up a 3 byte message to send */
uint8_t const BUFFER_SIZE = 3;
uint8_t buffer[BUFFER_SIZE];
buffer[0] = regaddr;
buffer[1] = (uint8_t)(regval >> 8);
buffer[2] = (uint8_t)(regval);
/* Write the register address followed by the data (no RESTART) */
I2C_SETADDRESS(priv->i2c, priv->addr, 7);
return I2C_WRITE(priv->i2c, buffer, BUFFER_SIZE);
}
/****************************************************************************
* Name: mcp9844_open
*
* Description:
* This function is called whenever the MCP9844 device is opened.
*
****************************************************************************/
static int mcp9844_open(FAR struct file *filep)
{
return OK;
}
/****************************************************************************
* Name: mcp9844_close
*
* Description:
* This routine is called when the MCP9844 device is closed.
*
****************************************************************************/
static int mcp9844_close(FAR struct file *filep)
{
return OK;
}
/****************************************************************************
* Name: mcp9844_read
****************************************************************************/
static ssize_t mcp9844_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: mcp9844_write
****************************************************************************/
static ssize_t mcp9844_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: lm75_ioctl
****************************************************************************/
static int mcp9844_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mcp9844_dev_s *priv = inode->i_private;
int ret = OK;
switch (cmd)
{
/* Read from the ambient temperature register. Arg: uint16_t* pointer */
case SNIOC_READTEMP:
{
FAR struct mcp9844_temp_arg_s *temp_result =
(FAR struct mcp9844_temp_arg_s *)((uintptr_t)arg);
DEBUGASSERT(temp_result != NULL);
/* Read the ambient temperature value from the device */
uint16_t raw_temperature = 0;
ret = mcp9844_read_u16(priv, MCP9844_TEMP_REG, &raw_temperature);
/* Convert from the proprietary sensor temperature data representation
* to a more user friendly version.
*/
if (ret == OK)
{
/* BIT15 - 13 contain information if preset temperature values
* have been exceeded or undercut. BIT12 is now not any longer
* needed since we do have the sign information retrieved.
* We do not need them for the temperature so those bits
* need to be masked out.
*/
raw_temperature &= 0x0FFF; /* 0x0FFF = 0b 0000 1111 1111 1111 */
/* The post comma temperature value is encoded in BIT3 to BIT0 */
temp_result->temp_post_comma = (uint8_t)(raw_temperature & 0x000F);
/* The pre comma temperature value is encoded in BIT11 to BIT4 */
temp_result->temp_pre_comma = (int8_t)(raw_temperature >> 4);
}
else
{
sndbg("ioctl::SNIOC_READTEMP - mcp9844_read_u16 failed - no temperature retrieved\n");
}
}
break;
case SNIOC_SETRESOLUTION:
{
ret = mcp9844_write_u16(priv, MCP9844_RESO_REG, (uint16_t)(arg));
if (ret != OK)
{
sndbg("ioctl::SNIOC_SETRESOLUTION - mcp9844_write_u16 failed - no resolution set\n");
}
}
break;
default:
sndbg("Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mcp9844_register
*
* Description:
* Register the MCP9844 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 MCP9844
* addr - The I2C address of the MCP9844.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int mcp9844_register(FAR const char *devpath, FAR struct i2c_dev_s *i2c,
uint8_t addr)
{
/* Sanity check */
DEBUGASSERT(i2c != NULL);
/* Initialize the LM-75 device structure */
FAR struct mcp9844_dev_s *priv =
(FAR struct mcp9844_dev_s *)kmm_malloc(sizeof(struct mcp9844_dev_s));
if (priv == NULL)
{
sndbg("Failed to allocate instance\n");
return -ENOMEM;
}
priv->i2c = i2c;
priv->addr = addr;
/* Register the character driver */
int ret = register_driver(devpath, &g_mcp9844_fops, 0666, priv);
if (ret < 0)
{
sndbg("Failed to register driver: %d\n", ret);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_I2C && CONFIG_I2C_LM75 */

128
include/nuttx/sensors/mcp9844.h Normal file
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@ -0,0 +1,128 @@
/****************************************************************************
* include/nuttx/sensors/mcp9844.h
*
* Copyright (C) 2016, DS-Automotion GmbH. All rights reserved.
* Author: Alexander Entinger <a.entinger@ds-automotion.com>
*
* 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_INCLUDE_NUTTX_SENSORS_MCP9844_H
#define __NUTTX_INCLUDE_NUTTX_SENSORS_MCP9844_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/fs/ioctl.h>
#if defined(CONFIG_I2C) && defined(CONFIG_MCP9844)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* IOCTL Commands ***********************************************************/
#define SNIOC_READTEMP _SNIOC(0x0001) /* Arg: mcp9844_temp_arg_s* pointer */
#define SNIOC_SETRESOLUTION _SNIOC(0x0002) /* Arg: uint16_t value */
/* MCP9844 Register Definitions *********************************************/
/* MCP9844 Registers addresses */
#define MCP9844_CAPA_REG (0x00) /* Sensor Capability Register */
#define MCP9844_CONF_REG (0x01) /* Sensor Configuration Register */
#define MCP9844_TEMP_REG (0x05) /* Sensor Temperature Register */
#define MCP9844_RESO_REG (0x09) /* Register to control the resolution of the temperature sensor */
/* Resolution Register Bit definitions */
#define MCP9844_RESO_REG_BIT_0 (1<<0)
#define MCP9844_RESO_REG_BIT_1 (1<<1)
/****************************************************************************
* Public Types
****************************************************************************/
struct mcp9844_temp_arg_s
{
int8_t temp_pre_comma;
uint8_t temp_post_comma;
};
enum mcp9844_resolution_e
{
RES_0_5 = 0,
RES_0_25 = MCP9844_RESO_REG_BIT_0,
RES_0_125 = MCP9844_RESO_REG_BIT_1,
RES_0_0625 = MCP9844_RESO_REG_BIT_1 | MCP9844_RESO_REG_BIT_0
};
struct i2c_dev_s;
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Name: mcp9844_register
*
* Description:
* Register the MCP9844 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 MCP9844
* addr - The I2C address of the MCP9844.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int mcp9844_register(FAR const char *devpath, FAR struct i2c_dev_s *i2c,
uint8_t addr);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_I2C && CONFIG_MCP9844 */
#endif /* __NUTTX_INCLUDE_NUTTX_SENSORS_MCP9844_H */