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incubator-nuttx/drivers/sensors/t67xx.c

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/****************************************************************************
* drivers/sensors/t67xx.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 <assert.h>
#include <errno.h>
#include <debug.h>
#include <string.h>
#include <time.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/random.h>
#include <nuttx/sensors/t67xx.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#if !defined(CONFIG_I2C)
# error i2c support required
#endif
/* This driver is tested with Telaire T6713. Likely works for Telaire T6703
* and other models as well, but this has not been verified. No test
* animals were gassed during testing.
*/
/* Modbus registers */
#define T67XX_REG_FWREV 0x1389 /* Firmware revision */
#define T67XX_REG_STATUS 0x138a /* Status */
#define T67XX_REG_GASPPM 0x138b /* Gas parts per million */
#define T67XX_REG_RESET 0x03e8 /* Reset device */
#define T67XX_REG_SPCAL 0x03ec /* Single point calibration */
#define T67XX_REG_SLAVEADDR 0x0fa5 /* Slave address */
#define T67XX_REG_ABCLOGIC 0x03ee /* ABC Logic enable/disable */
/* Status register bits */
#define T67XX_STATUS_ERROR (1 << 0) /* Error condition */
#define T67XX_STATUS_FLASH_ERROR (1 << 1) /* Flash error */
#define T67XX_STATUS_CALIB_ERROR (1 << 2) /* Calibration error */
/* [3:7] reserved */
#define T67XX_STATUS_RS232 (1 << 8) /* RS-232 error */
#define T67XX_STATUS_RS485 (1 << 9) /* RS-485 error */
#define T67XX_STATUS_I2C (1 << 10) /* I2C error */
#define T67XX_STATUS_WARMUP (1 << 11) /* Warm-up mode */
/* [12:14] reserved */
#define T67XX_STATUS_SPCAL (1 << 15) /* Single point calibration */
/* Command bits */
#define RESET_SENSOR 0xff00 /* Reset sensor */
#define SPCAL_START 0xff00 /* Start SP calibration */
#define SPCAL_STOP 0x0000 /* Stop SP calibration */
#define ABCLOGIC_ENABLE 0xff00 /* Enable ABC Logic */
#define ABCLOGIC_DISABLE 0x0000 /* Disable ABC Logic */
/* Required times before sensor reaches either minimal or full
* operational accuracy.
*/
#define T67XX_UPTIME_MINIMAL_SEC 120 /* two minutes */
#define T67XX_UPTIME_FULL_SEC (10 * 60) /* ten minutes */
#define T67XX_UPTIME_ABCLOGIC_SEC (24 * 60 * 60) /* a day */
/* I2C constants */
#define T67XX_I2C_FREQUENCY 100000 /* Only supported I2C speed */
#define T67XX_I2C_DELAY_MSEC 10 /* 5-10 ms recommended, 10 ms
* is always safe. */
/****************************************************************************
* Private Types
****************************************************************************/
struct t67xx_dev_s
{
FAR struct i2c_master_s *i2c; /* I2C interface */
uint8_t addr; /* I2C address */
struct timespec boot_time; /* When sensor was booted */
mutex_t devlock;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* I2C Helpers */
static int t67xx_read16(FAR struct t67xx_dev_s *priv, uint16_t regaddr,
FAR uint16_t *regvalue);
static int t67xx_write16(FAR struct t67xx_dev_s *priv, uint16_t regaddr,
FAR uint16_t regvalue, bool read_reply);
/* Driver features */
static int t67xx_check_status(FAR struct t67xx_dev_s *priv,
bool *warming_up, bool *calibrating);
static int t67xx_read_fwrev(FAR struct t67xx_dev_s *priv, uint16_t *rev);
static int t67xx_read_gas_ppm(FAR struct t67xx_dev_s *priv,
FAR struct t67xx_value_s *buffer);
static int t67xx_spcal(FAR struct t67xx_dev_s *priv, bool start);
static int t67xx_abclogic(FAR struct t67xx_dev_s *priv, bool enable);
static int t67xx_reset(FAR struct t67xx_dev_s *priv);
/* Character driver methods */
static ssize_t t67xx_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t t67xx_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int t67xx_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_t67xxfops =
{
NULL, /* open */
NULL, /* close */
t67xx_read, /* read */
t67xx_write, /* write */
NULL, /* seek */
t67xx_ioctl, /* ioctl */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: t67xx_read16
*
* Description:
* Read 16-bit register
*
****************************************************************************/
static int t67xx_read16(FAR struct t67xx_dev_s *priv, uint16_t regaddr,
FAR uint16_t *regvalue)
{
struct i2c_config_s config;
uint8_t buf[5];
uint8_t rxbuf[4] =
{
0
};
int ret;
DEBUGASSERT(priv != NULL);
DEBUGASSERT(regvalue != NULL);
/* Set up the I2C configuration. */
config.frequency = T67XX_I2C_FREQUENCY;
config.address = priv->addr;
config.addrlen = 7;
/* Set up the Modbus read request. */
buf[0] = 4;
buf[1] = (regaddr >> 8) & 0xff;
buf[2] = regaddr & 0xff;
buf[3] = 0;
buf[4] = 1;
/* Write the Modbus read request. */
ret = i2c_write(priv->i2c, &config, buf, sizeof(buf));
if (ret < 0)
{
snerr("ERROR: i2c_write failed: %d\n", ret);
return ret;
}
/* Wait and read response. */
up_mdelay(T67XX_I2C_DELAY_MSEC);
ret = i2c_read(priv->i2c, &config, rxbuf, sizeof(rxbuf));
if (ret < 0)
{
snerr("ERROR: i2c_read failed: %d\n", ret);
return ret;
}
if (rxbuf[0] != 4 || rxbuf[1] != 2)
{
#ifdef CONFIG_DEBUG_SENSORS_ERROR
lib_dumpbuffer("ERROR: sensor wrong data", rxbuf, sizeof(rxbuf));
#endif
return -EIO;
}
*regvalue = ((uint16_t)rxbuf[2] << 8) | rxbuf[3];
return ret;
}
/****************************************************************************
* Name: t67xx_write16
*
* Description:
* Write 16-bit register. If 'reply' is true, sensor response is read
* for verification.
*
****************************************************************************/
static int t67xx_write16(FAR struct t67xx_dev_s *priv, uint16_t regaddr,
FAR uint16_t regvalue, bool reply)
{
struct i2c_config_s config;
uint8_t buf[5];
uint8_t rxbuf[5] =
{
0
};
int ret;
DEBUGASSERT(priv != NULL);
/* Set up the I2C configuration. */
config.frequency = T67XX_I2C_FREQUENCY;
config.address = priv->addr;
config.addrlen = 7;
/* Set up the Modbus write request. */
buf[0] = 5;
buf[1] = (regaddr >> 8) & 0xff;
buf[2] = regaddr & 0xff;
buf[3] = (regvalue >> 8) & 0xff;
buf[4] = regvalue & 0xff;
/* Write the Modbus write request. */
ret = i2c_write(priv->i2c, &config, buf, sizeof(buf));
if (ret < 0)
{
snerr("ERROR: i2c_write failed: %d\n", ret);
return ret;
}
/* There is no reply for Reset command, exit early. */
if (!reply)
{
return ret;
}
/* Wait and read response. */
up_mdelay(T67XX_I2C_DELAY_MSEC);
ret = i2c_read(priv->i2c, &config, rxbuf, sizeof(rxbuf));
if (ret < 0)
{
snerr("ERROR: i2c_read failed: %d\n", ret);
return ret;
}
if (memcmp(rxbuf, buf, sizeof(rxbuf)) != 0)
{
#ifdef CONFIG_DEBUG_SENSORS_ERROR
lib_dumpbuffer("ERROR: sensor wrong data", rxbuf, sizeof(rxbuf));
#endif
return -EIO;
}
return ret;
}
/****************************************************************************
* Name: t67xx_check_status
*
* Description:
* Check status register.
*
****************************************************************************/
static int t67xx_check_status(FAR struct t67xx_dev_s *priv,
bool *warming_up, bool *calibrating)
{
uint16_t status;
int ret;
/* Read the status register. */
ret = t67xx_read16(priv, T67XX_REG_STATUS, &status);
if (ret < 0)
{
snerr("ERROR: sensor cannot read status: %d\n", ret);
return ret;
}
sninfo("status 0x%04x\n", status);
/* We ignore I2C error here, as it is checked for every bus
* operation anyway.
*/
if (status & (T67XX_STATUS_ERROR |
T67XX_STATUS_FLASH_ERROR | T67XX_STATUS_CALIB_ERROR))
{
snerr("ERROR: sensor error 0x%04x\n", status);
return ERROR;
}
*warming_up = status & T67XX_STATUS_WARMUP;
*calibrating = status & T67XX_STATUS_SPCAL;
return OK;
}
/****************************************************************************
* Name: t67xx_read_fwrev
*
* Description:
* Check firmware revision register.
*
****************************************************************************/
static int t67xx_read_fwrev(FAR struct t67xx_dev_s *priv, uint16_t *rev)
{
uint16_t fwrev;
int ret;
/* Read the FW revision register. */
ret = t67xx_read16(priv, T67XX_REG_FWREV, &fwrev);
if (ret < 0)
{
snerr("ERROR: sensor cannot read reg: %d\n", ret);
return ret;
}
sninfo("sensor FW rev: 0x%04x\n", fwrev);
if (rev)
{
*rev = fwrev;
}
return OK;
}
/****************************************************************************
* Name: has_time_passed
*
* Description:
* Return true if curr >= start + secs_since_start
*
****************************************************************************/
static bool has_time_passed(struct timespec curr,
struct timespec start,
unsigned int secs_since_start)
{
if ((long)((start.tv_sec + secs_since_start) - curr.tv_sec) == 0)
{
return start.tv_nsec <= curr.tv_nsec;
}
return (long)((start.tv_sec + secs_since_start) - curr.tv_sec) <= 0;
}
/****************************************************************************
* Name: t67xx_read_gas_ppm
*
* Description:
* Read the current carbon dioxide level.
*
****************************************************************************/
static int t67xx_read_gas_ppm(FAR struct t67xx_dev_s *priv,
FAR struct t67xx_value_s *buffer)
{
uint16_t ppm;
bool warming_up;
bool calibrating;
struct timespec ts;
int ret;
clock_systime_timespec(&ts);
if (!has_time_passed(ts, priv->boot_time, T67XX_UPTIME_MINIMAL_SEC))
{
snwarn("WARN: sensor not ready yet\n");
return -EAGAIN;
}
/* Check sensor status. */
ret = t67xx_check_status(priv, &warming_up, &calibrating);
if (ret != OK)
{
return ret;
}
/* Sanity check warm-up behavior. */
if (!has_time_passed(ts, priv->boot_time, T67XX_UPTIME_FULL_SEC))
{
if (!warming_up)
{
snwarn("WARN: sensor not fully warm-up\n");
warming_up = true;
}
}
else if (warming_up)
{
snwarn("WARN: sensor still warming up after %d secs\n",
T67XX_UPTIME_FULL_SEC);
}
/* Read the CO2 level. */
ret = t67xx_read16(priv, T67XX_REG_GASPPM, &ppm);
if (ret < 0)
{
return ret;
}
add_sensor_randomness(ts.tv_nsec ^ (int)ppm);
buffer->gas_ppm = ppm;
buffer->warming_up = warming_up;
buffer->calibrating = calibrating;
sninfo("ppm %d, warming up %d, calibrating %d\n",
(int)ppm, warming_up, calibrating);
return OK;
}
/****************************************************************************
* Name: t67xx_spcal
*
* Description:
* Start or stop sensor single-point calibration.
*
****************************************************************************/
static int t67xx_spcal(FAR struct t67xx_dev_s *priv, bool start)
{
int ret;
ret = t67xx_write16(priv, T67XX_REG_SPCAL,
start ? SPCAL_START : SPCAL_STOP, true);
if (ret < 0)
{
snerr("ERROR: sp calibration failed: %d\n", ret);
return ret;
}
return ret;
}
/****************************************************************************
* Name: t67xx_abclogic
*
* Description:
* Start or stop sensor ABC Logic feature.
*
* Automatic Background Logic, is a self-calibration technique that is
* designed to be used in applications where concentrations will drop to
* outside ambient conditions (400 ppm) at least three times in a 7 days.
*
* With ABC Logic enabled, the sensor will typically reach its operational
* accuracy after 24 hours of continuous operation at a condition that it
* was exposed to ambient reference levels of air at 400 ppm CO2. Sensor
* will maintain accuracy specifications with ABC Logic enabled, given
* that it is at least four times in 21 days exposed to the reference
* value and this reference value is the lowest concentration to which
* the sensor is exposed. ABC Logic requires continuous operation of the
* sensor for periods of at least 24 hours.
*
* Currently driver does not try to check for these constraints.
*
****************************************************************************/
static int t67xx_abclogic(FAR struct t67xx_dev_s *priv, bool enable)
{
int ret;
ret = t67xx_write16(priv, T67XX_REG_ABCLOGIC,
enable ? ABCLOGIC_ENABLE : ABCLOGIC_DISABLE, true);
if (ret < 0)
{
snerr("ERROR: ABC Logic failed: %d\n", ret);
return ret;
}
return ret;
}
/****************************************************************************
* Name: t67xx_reset
*
* Description:
* Reset sensor. Data-sheet does not recommend using this.
*
****************************************************************************/
static int t67xx_reset(FAR struct t67xx_dev_s *priv)
{
int ret;
ret = t67xx_write16(priv, T67XX_REG_RESET, RESET_SENSOR, false);
if (ret < 0)
{
snerr("ERROR: reset failed: %d\n", ret);
return ret;
}
/* Sensor uptime starting again from zero. */
clock_systime_timespec(&priv->boot_time);
return ret;
}
/****************************************************************************
* Name: t67xx_read
****************************************************************************/
static ssize_t t67xx_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct t67xx_dev_s *priv = inode->i_private;
FAR struct t67xx_value_s *ptr;
ssize_t nsamples;
int i;
int ret;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
/* How many samples were requested to get? */
nsamples = buflen / sizeof(struct t67xx_value_s);
ptr = (FAR struct t67xx_value_s *)buffer;
sninfo("buflen: %d nsamples: %d\n", buflen, nsamples);
/* Get the requested number of samples */
for (i = 0; i < nsamples; i++)
{
struct t67xx_value_s gas_ppm;
/* Read the next struct t67xx_value_s */
ret = t67xx_read_gas_ppm(priv, &gas_ppm);
if (ret < 0)
{
snerr("ERROR: t67xx_read_gas_ppm failed: %d\n", ret);
nxmutex_unlock(&priv->devlock);
return (ssize_t)ret;
}
/* Save the value in the user buffer */
*ptr++ = gas_ppm;
}
nxmutex_unlock(&priv->devlock);
return nsamples * sizeof(struct t67xx_value_s);
}
/****************************************************************************
* Name: t67xx_write
****************************************************************************/
static ssize_t t67xx_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: t67xx_ioctl
****************************************************************************/
static int t67xx_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct t67xx_dev_s *priv = inode->i_private;
int ret;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
switch (cmd)
{
/* Soft reset the sensor, Arg: None */
case SNIOC_RESET:
ret = t67xx_reset(priv);
sninfo("reset ret: %d\n", ret);
break;
/* Dump registers, currently just FWREV reg, Arg: None */
case SNIOC_DUMP_REGS:
ret = t67xx_read_fwrev(priv, NULL);
break;
/* Calibrate the sensor, Arg: uint8_t value */
case SNIOC_SPCALIB:
ret = t67xx_spcal(priv, !!arg);
sninfo("spcal ret: %d\n", ret);
break;
/* Enable/disable the ABC Logic feature, Arg: uint8_t value */
case SNIOC_ABCLOGIC:
ret = t67xx_abclogic(priv, !!arg);
sninfo("abclogic ret: %d\n", ret);
break;
default:
sninfo("Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
nxmutex_unlock(&priv->devlock);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: t67xx_register
*
* Description:
* Register the T67XX character device as 'devpath'
*
* Input Parameters:
* devpath - The full path to the driver to register. E.g., "/dev/co2_0"
* i2c - An instance of the I2C interface to use to communicate with T67XX
* addr - The I2C address of the T67XX. For T6713 this is initially 0x15
* but it can be changed by the SLAVE ADDRESS command.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int t67xx_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
uint8_t addr)
{
FAR struct t67xx_dev_s *priv;
int ret;
DEBUGASSERT(i2c != NULL);
DEBUGASSERT(addr == T67XX_I2C_ADDR);
/* Initialize the t67xx device structure. */
priv = kmm_malloc(sizeof(struct t67xx_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->i2c = i2c;
priv->addr = addr;
nxmutex_init(&priv->devlock);
clock_systime_timespec(&priv->boot_time);
/* Register the character driver. */
ret = register_driver(devpath, &g_t67xxfops, 0666, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register driver: %d\n", ret);
goto errout;
}
sninfo("(addr=0x%02x) registered at %s\n", priv->addr, devpath);
return ret;
errout:
nxmutex_destroy(&priv->devlock);
kmm_free(priv);
return ret;
}
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