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incubator-nuttx/drivers/sensors/mlx90614.c

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/****************************************************************************
* drivers/sensors/mlx90614.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/* Character driver for the Melexis MLX90614 Infrared Thermometer */
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <stdlib.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/signal.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/sensors/ioctl.h>
#include <nuttx/sensors/mlx90614.h>
#include <nuttx/random.h>
#ifdef CONFIG_MLX90614_CRC
#include <nuttx/crc8.h>
#endif
#if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_MLX90614)
/****************************************************************************
* Pre-process Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
struct mlx90614_dev_s
{
FAR struct i2c_master_s *i2c; /* I2C interface */
uint8_t addr; /* I2C address */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* I2C Helpers */
static int mlx90614_read_word(FAR struct mlx90614_dev_s *priv,
uint8_t cmd, FAR uint16_t *regval);
static int mlx90614_write_word(FAR struct mlx90614_dev_s *priv,
uint8_t cmd, uint16_t regval);
/* Character driver methods */
static ssize_t mlx90614_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t mlx90614_write(FAR struct file *filep,
FAR const char *buffer, size_t buflen);
static int mlx90614_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_mlx90614_fops =
{
NULL, /* open */
NULL, /* close */
mlx90614_read, /* read */
mlx90614_write, /* write */
NULL, /* seek */
mlx90614_ioctl, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: mlx90614_read_word
*
* Description:
* Read 16-bit register
*
****************************************************************************/
static int mlx90614_read_word(FAR struct mlx90614_dev_s *priv, uint8_t cmd,
FAR uint16_t *regval)
{
struct i2c_config_s config;
#ifdef CONFIG_MLX90614_CRC
uint8_t checkcrc[6];
uint8_t *buffer;
#else
uint8_t buffer[3];
#endif
uint8_t crc;
int ret;
#ifdef CONFIG_MLX90614_CRC
/* Recreate the I2C byte sequence to check the CRC PEC field */
checkcrc[0] = I2C_WRITEADDR8(priv->addr);
checkcrc[1] = cmd;
checkcrc[2] = I2C_READADDR8(priv->addr);
/* Point "buffer" to checkcrc[3] to fill it with received bytes */
buffer = (FAR uint8_t *)&checkcrc[3];
#endif
/* Set up the I2C configuration */
config.frequency = 100000;
config.address = priv->addr;
config.addrlen = 7;
/* Write the Command and read 16-bits + PEC from the device */
ret = i2c_writeread(priv->i2c, &config, (FAR const uint8_t *) &cmd, 1,
buffer, 3);
if (ret < 0)
{
snerr ("i2c_writeread failed: %d\n", ret);
return ret;
}
/* Copy the content of the buffer to the location of the uint16_t pointer */
*regval = (uint16_t)(buffer[0] | (buffer[1] << 8));
sninfo("value[0]: %02x | value[1]: %02x | value[2]: %02x | ret: %d\n",
buffer[0], buffer[1], buffer[2], ret);
#ifdef CONFIG_MLX90614_CRC
crc = crc8ccitt(checkcrc, 5);
sninfo("Calculated CRC: 0x%02X\n", crc);
if (crc != buffer[2])
{
snerr("Invalid CRC! Expected: 0x%02X read: 0x%02X\n", crc, buffer[2]);
return -EFAULT;
}
#endif
return OK;
}
/****************************************************************************
* Name: mlx90614_write_word
*
* Description:
* Write to a 16-bit register
*
****************************************************************************/
static int mlx90614_write_word(FAR struct mlx90614_dev_s *priv, uint8_t cmd,
uint16_t regval)
{
struct i2c_config_s config;
uint8_t pkgcrc[5];
uint8_t *buffer;
uint8_t crc;
int ret;
/* Set up the I2C configuration */
config.frequency = 100000;
config.address = priv->addr;
config.addrlen = 7;
/* First write 0x00 0x00 to erase the EEPROM */
pkgcrc[0] = I2C_WRITEADDR8(priv->addr);
pkgcrc[1] = cmd;
pkgcrc[2] = 0x00;
pkgcrc[3] = 0x00;
/* Generate the CRC to put in the PEC field */
crc = crc8ccitt(pkgcrc, 4);
sninfo("Generated CRC: 0x%02X\n", crc);
pkgcrc[4] = crc;
buffer = &(pkgcrc[1]);
/* Write the Command + 2 Bytes + PEC to device */
ret = i2c_write(priv->i2c, &config, (FAR const uint8_t *) buffer, 4);
if (ret < 0)
{
snerr ("i2c_writeread failed: %d\n", ret);
return ret;
}
/* Wait the EEPROM erase */
nxsig_usleep(10 * 1000);
/* Create the I2C command that will be sent to device */
pkgcrc[0] = I2C_WRITEADDR8(priv->addr);
pkgcrc[1] = cmd;
pkgcrc[2] = (regval & 0xff);
pkgcrc[3] = (regval & 0xff00) >> 8;
/* Generate the CRC to put in the PEC field */
crc = crc8ccitt(pkgcrc, 4);
sninfo("Generated CRC: 0x%02X\n", crc);
pkgcrc[4] = crc;
/* Write the Command + 2 Bytes + PEC to device */
ret = i2c_write(priv->i2c, &config, (FAR const uint8_t *) buffer, 4);
if (ret < 0)
{
snerr ("i2c_writeread failed: %d\n", ret);
return ret;
}
sninfo("New address 0x%02x stored correctly!\n", regval);
return OK;
}
/****************************************************************************
* Name: mlx90614_read
****************************************************************************/
static ssize_t mlx90614_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode;
FAR struct mlx90614_dev_s *priv;
FAR struct mlx90614_temp_s *temp = (FAR struct mlx90614_temp_s *)buffer;
uint8_t cmd;
int ret;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Check if the user is reading the right size */
if (buflen != sizeof(struct mlx90614_temp_s))
{
snerr("ERROR: You need to read 2 bytes from this sensor!\n");
return -EINVAL;
}
/* Read Ambient Temperature sensor */
cmd = MLX90614_CMD_RAM_ACCESS | MLX90614_TA;
ret = mlx90614_read_word(priv, cmd, &(temp->ta));
if (ret < 0)
{
snerr("ERROR: Error reading thermometer sensor!\n");
return ret;
}
/* Read Object1 Temperature sensor */
cmd = MLX90614_CMD_RAM_ACCESS | MLX90614_TOBJ1;
ret = mlx90614_read_word(priv, cmd, &(temp->tobj1));
if (ret < 0)
{
snerr("ERROR: Error reading thermometer sensor!\n");
return ret;
}
/* Read Object2 Temperature sensor - some sensor doesn't have it */
cmd = MLX90614_CMD_RAM_ACCESS | MLX90614_TOBJ2;
ret = mlx90614_read_word(priv, cmd, &(temp->tobj2));
if (ret < 0)
{
snerr("ERROR: Error reading thermometer sensor!\n");
return ret;
}
return buflen;
}
/****************************************************************************
* Name: mlx90614_write
****************************************************************************/
static ssize_t mlx90614_write(FAR struct file *filep,
FAR const char *buffer, size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: mlx90614_ioctl
****************************************************************************/
static int mlx90614_ioctl(FAR struct file *filep, int cmd,
unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mlx90614_dev_s *priv = inode->i_private;
int ret = OK;
switch (cmd)
{
/* Change the device to use a new i2c/smbus address */
case SNIOC_CHANGE_SMBUSADDR:
{
FAR struct mlx90614_dev_s newdev;
FAR uint8_t *ptr = (FAR uint8_t *)((uintptr_t)arg);
uint16_t newaddr;
uint8_t smbcmd;
/* EEPROM reflash only happen when sent at I2C address 0x00 */
newdev.i2c = priv->i2c;
newdev.addr = 0x00;
/* The I2C address is put in the high byte position */
newaddr = (uint16_t) *ptr;
sninfo("Setting new address: 0x%02x\n", newaddr);
smbcmd = MLX90614_CMD_EEPROM_ACCESS | MLX90614_SMBUS_ADDR;
ret = mlx90614_write_word(&newdev, smbcmd, newaddr);
if (ret < 0)
{
snerr("ERROR: Failed to change the I2C/SMBus address!\n");
}
}
break;
default:
snerr("ERROR: Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mlx90614_register
*
* Description:
* Register the MLX90614 character device as 'devpath'
*
* Input Parameters:
* devpath - The full path to the driver to register. E.g., "/dev/therm0"
* i2c - An instance of the I2C interface to use to communicate with
* MLX90614
* addr - The I2C address of the MLX90614.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int mlx90614_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
uint8_t addr)
{
int ret;
/* Sanity check */
DEBUGASSERT(i2c != NULL);
/* Initialize the MLX90614 device structure */
FAR struct mlx90614_dev_s *priv =
kmm_malloc(sizeof(struct mlx90614_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->i2c = i2c;
priv->addr = addr;
/* Register the character driver */
ret = register_driver(devpath, &g_mlx90614_fops, 0666, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register driver: %d\n", ret);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_I2C && CONFIG_SENSORS_MLX90614 */
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