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incubator-nuttx/drivers/sensors/lm92.c

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/****************************************************************************
* drivers/sensors/lm92.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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdlib.h>
#include <fixedmath.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/sensors/lm92.h>
#include <nuttx/random.h>
#if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_LM92)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef CONFIG_LM92_I2C_FREQUENCY
# define CONFIG_LM92_I2C_FREQUENCY 400000
#endif
/* Centigrade to Fahrenheit conversion: F = 9*C/5 + 32 */
#define B16_9DIV5 (9 * 65536 / 5)
#define B16_32 (32 * 65536)
/****************************************************************************
* Private
****************************************************************************/
struct lm92_dev_s
{
FAR struct i2c_master_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 lm92_i2c_write(FAR struct lm92_dev_s *priv,
FAR const uint8_t *buffer, int buflen);
static int lm92_i2c_read(FAR struct lm92_dev_s *priv,
FAR uint8_t *buffer, int buflen);
static int lm92_readb16(FAR struct lm92_dev_s *priv, uint8_t regaddr,
FAR b16_t *regvalue);
static int lm92_writeb16(FAR struct lm92_dev_s *priv, uint8_t regaddr,
b16_t regval);
static int lm92_readtemp(FAR struct lm92_dev_s *priv, FAR b16_t *temp);
static int lm92_readconf(FAR struct lm92_dev_s *priv, FAR uint8_t *conf);
static int lm92_writeconf(FAR struct lm92_dev_s *priv, uint8_t conf);
/* Character driver methods */
static ssize_t lm92_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t lm92_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int lm92_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_lm92fops =
{
NULL, /* open */
NULL, /* close */
lm92_read, /* read */
lm92_write, /* write */
NULL, /* seek */
lm92_ioctl, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: lm92_i2c_write
*
* Description:
* Write to the I2C device.
*
****************************************************************************/
static int lm92_i2c_write(FAR struct lm92_dev_s *priv,
FAR const uint8_t *buffer, int buflen)
{
struct i2c_msg_s msg;
int ret;
/* Setup for the transfer */
msg.frequency = CONFIG_LM92_I2C_FREQUENCY,
msg.addr = priv->addr;
msg.flags = 0;
msg.buffer = (FAR uint8_t *)buffer; /* Override const */
msg.length = buflen;
/* Then perform the transfer. */
ret = I2C_TRANSFER(priv->i2c, &msg, 1);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: lm92_i2c_read
*
* Description:
* Read from the I2C device.
*
****************************************************************************/
static int lm92_i2c_read(FAR struct lm92_dev_s *priv,
FAR uint8_t *buffer, int buflen)
{
struct i2c_msg_s msg;
int ret;
/* Setup for the transfer */
msg.frequency = CONFIG_LM92_I2C_FREQUENCY,
msg.addr = priv->addr,
msg.flags = I2C_M_READ;
msg.buffer = buffer;
msg.length = buflen;
/* Then perform the transfer. */
ret = I2C_TRANSFER(priv->i2c, &msg, 1);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: lm92_readb16
*
* Description:
* Read a 16-bit register (LM92_TEMP_REG, LM92_THYS_REG, LM92_TCRIT_REG,
* LM92_TLOW_REG, LM92_THIGH_REG, or LM92_ID_REG)
*
****************************************************************************/
static int lm92_readb16(FAR struct lm92_dev_s *priv, uint8_t regaddr,
FAR b16_t *regvalue)
{
uint8_t buffer[2];
int ret;
/* Write the register address */
ret = lm92_i2c_write(priv, &regaddr, 1);
if (ret < 0)
{
snerr("ERROR: i2c_write failed: %d\n", ret);
return ret;
}
/* Restart and read 16 bits from the register (discarding 3) */
ret = lm92_i2c_read(priv, buffer, 2);
if (ret < 0)
{
snerr("ERROR: i2c_read failed: %d\n", ret);
return ret;
}
/* Data format is:
* TTTTTTTT TTTTTxxx where TTTTTTTTTTTTT is a thirteen-bit,
* signed temperature value with LSB = 0.0625 degrees Centigrade.
*/
*regvalue = (b16_t)((uint32_t)(buffer[0] & (1 << 7)) << 24 |
(uint32_t)(buffer[0] & ~(1 << 7)) << 17 |
(uint32_t)(buffer[1] & ~7) << 9);
sninfo("addr: %02x value: %08x ret: %d\n", regaddr, *regvalue, ret);
return OK;
}
/****************************************************************************
* Name: lm92_writeb16
*
* Description:
* Write to a 16-bit register
* (LM92_TEMP_REG, LM92_THYS_REG, LM92_TCRIT_REG,
* LM92_TLOW_REG, LM92_THIGH_REG, or LM92_ID_REG)
*
****************************************************************************/
static int lm92_writeb16(FAR struct lm92_dev_s *priv, uint8_t regaddr,
b16_t regval)
{
uint8_t buffer[3];
sninfo("addr: %02x value: %08x\n", regaddr, regval);
/* Set up a 3-byte message to send */
buffer[0] = regaddr;
buffer[1] = (uint8_t)(((uint32_t)regval & (1 << 31)) >> 24 |
((uint32_t)regval & ~(1 << 31)) >> 17);
buffer[2] = (uint8_t)(((uint32_t)regval & ~(1 << 31)) >> 9);
/* Write the register address followed by the data (no RESTART) */
return lm92_i2c_write(priv, buffer, 3);
}
/****************************************************************************
* Name: lm92_readtemp
*
* Description:
* Read the temperature register with special scaling (LM92_TEMP_REG)
*
****************************************************************************/
static int lm92_readtemp(FAR struct lm92_dev_s *priv, FAR b16_t *temp)
{
b16_t temp16;
int ret;
/* Read the raw temperature data (b16_t) */
ret = lm92_readb16(priv, LM92_TEMP_REG, &temp16);
if (ret < 0)
{
snerr("ERROR: lm92_readb16 failed: %d\n", ret);
return ret;
}
add_sensor_randomness(temp16);
sninfo("Centigrade: %08x\n", temp16);
/* Was Fahrenheit requested? */
if (priv->fahrenheit)
{
/* Centigrade to Fahrenheit conversion: F = 9*C/5 + 32 */
temp16 = b16mulb16(temp16, B16_9DIV5) + B16_32;
sninfo("Fahrenheit: %08x\n", temp16);
}
*temp = temp16;
return OK;
}
/****************************************************************************
* Name: lm92_readconf
*
* Description:
* Read the 8-bit LM92 configuration register
*
****************************************************************************/
static int lm92_readconf(FAR struct lm92_dev_s *priv, FAR uint8_t *conf)
{
uint8_t buffer;
int ret;
/* Write the configuration register address */
buffer = LM92_CONF_REG;
ret = lm92_i2c_write(priv, &buffer, 1);
if (ret < 0)
{
snerr("ERROR: i2c_write failed: %d\n", ret);
return ret;
}
/* Restart and read 8 bits from the register */
ret = lm92_i2c_read(priv, conf, 1);
sninfo("conf: %02x ret: %d\n", *conf, ret);
return ret;
}
/****************************************************************************
* Name: lm92_writeconf
*
* Description:
* Write to a 8-bit LM92 configuration register.
*
****************************************************************************/
static int lm92_writeconf(FAR struct lm92_dev_s *priv, uint8_t conf)
{
uint8_t buffer[2];
sninfo("conf: %02x\n", conf);
/* Set up a 2-byte message to send */
buffer[0] = LM92_CONF_REG;
buffer[1] = conf;
/* Write the register address followed by the data (no RESTART) */
return lm92_i2c_write(priv, buffer, 2);
}
/****************************************************************************
* Name: lm92_readid
*
* Description:
* Read the 16-bit LM92 identification register
*
****************************************************************************/
static int lm92_readid(FAR struct lm92_dev_s *priv, FAR uint16_t *id)
{
uint8_t buffer[2];
uint8_t regaddr;
int ret;
/* Write the identification register address */
regaddr = LM92_ID_REG;
ret = lm92_i2c_write(priv, &regaddr, 1);
if (ret < 0)
{
snerr("ERROR: i2c_write failed: %d\n", ret);
return ret;
}
/* Restart and read 16 bits from the register */
ret = lm92_i2c_read(priv, buffer, 2);
if (ret < 0)
{
snerr("ERROR: i2c_read failed: %d\n", ret);
return ret;
}
*id = (uint16_t)buffer[0] << 8 | (uint16_t)buffer[1];
sninfo("id: %04x ret: %d\n", *id, ret);
return OK;
}
/****************************************************************************
* Name: lm92_read
****************************************************************************/
static ssize_t lm92_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lm92_dev_s *priv = inode->i_private;
FAR b16_t *ptr;
ssize_t nsamples;
int i;
int ret;
/* How many samples were requested to get? */
nsamples = buflen / sizeof(b16_t);
ptr = (FAR b16_t *)buffer;
sninfo("buflen: %d nsamples: %d\n", buflen, nsamples);
/* Get the requested number of samples */
for (i = 0; i < nsamples; i++)
{
b16_t temp = 0;
/* Read the next b16_t temperature value */
ret = lm92_readtemp(priv, &temp);
if (ret < 0)
{
snerr("ERROR: lm92_readtemp failed: %d\n", ret);
return (ssize_t)ret;
}
/* Save the temperature value in the user buffer */
*ptr++ = temp;
}
return nsamples * sizeof(b16_t);
}
/****************************************************************************
* Name: lm92_write
****************************************************************************/
static ssize_t lm92_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: lm92_ioctl
****************************************************************************/
static int lm92_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct lm92_dev_s *priv = inode->i_private;
int ret = OK;
switch (cmd)
{
/* Read from the configuration register. Arg: uint8_t* pointer */
case SNIOC_READCONF:
{
FAR uint8_t *ptr = (FAR uint8_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = lm92_readconf(priv, ptr);
sninfo("conf: %02x ret: %d\n", *ptr, ret);
}
break;
/* Write to the configuration register. Arg: uint8_t value */
case SNIOC_WRITECONF:
ret = lm92_writeconf(priv, (uint8_t)arg);
sninfo("conf: %02x ret: %d\n", *(uint8_t *)arg, ret);
break;
/* Shutdown the LM92. Arg: None */
case SNIOC_SHUTDOWN:
{
uint8_t conf;
ret = lm92_readconf(priv, &conf);
if (ret == OK)
{
ret = lm92_writeconf(priv, conf | LM92_CONF_SHUTDOWN);
}
sninfo("conf: %02x ret: %d\n", conf | LM92_CONF_SHUTDOWN, ret);
}
break;
/* Powerup the LM92. Arg: None */
case SNIOC_POWERUP:
{
uint8_t conf;
ret = lm92_readconf(priv, &conf);
if (ret == OK)
{
ret = lm92_writeconf(priv, conf & ~LM92_CONF_SHUTDOWN);
}
sninfo("conf: %02x ret: %d\n", conf & ~LM92_CONF_SHUTDOWN, ret);
}
break;
/* Report samples in Fahrenheit. Arg: None */
case SNIOC_FAHRENHEIT:
priv->fahrenheit = true;
sninfo("Fahrenheit\n");
break;
/* Report samples in Centigrade. Arg: None */
case SNIOC_CENTIGRADE:
priv->fahrenheit = false;
sninfo("Centigrade\n");
break;
/* Read THYS temperature register. Arg: b16_t* pointer */
case SNIOC_READTHYS:
{
FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = lm92_readb16(priv, LM92_THYS_REG, ptr);
sninfo("THYS: %08x ret: %d\n", *ptr, ret);
}
break;
/* Write THYS temperature register. Arg: b16_t value */
case SNIOC_WRITETHYS:
ret = lm92_writeb16(priv, LM92_THYS_REG, (b16_t)arg);
sninfo("THYS: %08x ret: %d\n", (b16_t)arg, ret);
break;
/* Read TCRIT temperature register. Arg: b16_t* pointer */
case SNIOC_READTCRIT:
{
FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = lm92_readb16(priv, LM92_TCRIT_REG, ptr);
sninfo("TCRIT: %08x ret: %d\n", *ptr, ret);
}
break;
/* Write TCRIT temperature register. Arg: b16_t value */
case SNIOC_WRITETCRIT:
ret = lm92_writeb16(priv, LM92_TCRIT_REG, (b16_t)arg);
sninfo("TCRIT: %08x ret: %d\n", (b16_t)arg, ret);
break;
/* Read TLOW temperature register. Arg: b16_t* pointer */
case SNIOC_READTLOW:
{
FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = lm92_readb16(priv, LM92_TLOW_REG, ptr);
sninfo("TLOW: %08x ret: %d\n", *ptr, ret);
}
break;
/* Write TLOW temperature register. Arg: b16_t value */
case SNIOC_WRITETLOW:
ret = lm92_writeb16(priv, LM92_TLOW_REG, (b16_t)arg);
sninfo("TLOW: %08x ret: %d\n", (b16_t)arg, ret);
break;
/* Read THIGH temperature register. Arg: b16_t* pointer */
case SNIOC_READTHIGH:
{
FAR b16_t *ptr = (FAR b16_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = lm92_readb16(priv, LM92_THIGH_REG, ptr);
sninfo("THIGH: %08x ret: %d\n", *ptr, ret);
}
break;
/* Write THIGH temperature register. Arg: b16_t value */
case SNIOC_WRITETHIGH:
ret = lm92_writeb16(priv, LM92_THIGH_REG, (b16_t)arg);
sninfo("THIGH: %08x ret: %d\n", (b16_t)arg, ret);
break;
/* Read from the identification register. Arg: uint16_t* pointer */
case SNIOC_READID:
{
FAR uint16_t *ptr = (FAR uint16_t *)((uintptr_t)arg);
DEBUGASSERT(ptr != NULL);
ret = lm92_readid(priv, ptr);
sninfo("id: %04x ret: %d\n", *ptr, ret);
}
break;
default:
snerr("ERROR: Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lm92_register
*
* Description:
* Register the LM92 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 the LM92.
* addr - The I2C address of the LM92. The base I2C address of the LM92
* is 0x48. Bits 0-2 can be controlled to get 4 unique addresses
* from 0x48 through 0x4b.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int lm92_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
uint8_t addr)
{
FAR struct lm92_dev_s *priv;
int ret;
/* Sanity check */
DEBUGASSERT(i2c != NULL);
DEBUGASSERT(addr == CONFIG_LM92_ADDR0 || addr == CONFIG_LM92_ADDR1 ||
addr == CONFIG_LM92_ADDR2 || addr == CONFIG_LM92_ADDR3);
/* Initialize the LM92 device structure */
priv = kmm_malloc(sizeof(struct lm92_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->i2c = i2c;
priv->addr = addr;
priv->fahrenheit = false;
/* Register the character driver */
ret = register_driver(devpath, &g_lm92fops, 0666, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register driver: %d\n", ret);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_I2C && CONFIG_SENSORS_LM92 */
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