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nuttx/drivers/sensors/sht3x.c

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/****************************************************************************
* drivers/sensors/sht3x.c
* Driver for the Sensirion SHT3x temperature and humidity sensors
*
* Copyright (C) 2019 Haltian Ltd, Hexagon AB. All rights reserved.
* Author: Jussi Kivilinna <jussi.kivilinna@haltian.com>,
* Markus Bernet <markus.bernet@hexagon.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 <stdio.h>
#include <errno.h>
#include <debug.h>
#include <time.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/sensors/sht3x.h>
#include <nuttx/random.h>
#if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_SHT3X)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifdef CONFIG_SHT3X_DEBUG
# define sht3x_dbg(x, ...) _info(x, ##__VA_ARGS__)
#else
# define sht3x_dbg(x, ...) sninfo(x, ##__VA_ARGS__)
#endif
#ifndef CONFIG_SHT3X_I2C_FREQUENCY
# define CONFIG_SHT3X_I2C_FREQUENCY 400000
#endif
/* Commands */
#define SHT3X_READ_SERIALNBR 0x3780 /* read serial number */
#define SHT3X_READ_STATUS 0xF32D /* read status register */
#define SHT3X_CLEAR_STATUS 0x3041 /* clear status register */
#define SHT3X_HEATER_ENABLE 0x306D /* enabled heater */
#define SHT3X_HEATER_DISABLE 0x3066 /* disable heater */
#define SHT3X_SOFT_RESET 0x30A2 /* soft reset */
#define SHT3X_MEAS_CLOCKSTR_H 0x2C06 /* measurement: clock stretching, high repeatability */
#define SHT3X_MEAS_CLOCKSTR_M 0x2C0D /* measurement: clock stretching, medium repeatability */
#define SHT3X_MEAS_CLOCKSTR_L 0x2C10 /* measurement: clock stretching, low repeatability */
#define SHT3X_MEAS_POLLING_H 0x2400 /* measurement: polling, high repeatability */
#define SHT3X_MEAS_POLLING_M 0x240B /* measurement: polling, medium repeatability */
#define SHT3X_MEAS_POLLING_L 0x2416 /* measurement: polling, low repeatability */
#define SHT3X_MEAS_PERI_05_H 0x2032 /* measurement: periodic 0.5 mps, high repeatability */
#define SHT3X_MEAS_PERI_05_M 0x2024 /* measurement: periodic 0.5 mps, medium repeatability */
#define SHT3X_MEAS_PERI_05_L 0x202F /* measurement: periodic 0.5 mps, low repeatability */
#define SHT3X_MEAS_PERI_1_H 0x2130 /* measurement: periodic 1 mps, high repeatability */
#define SHT3X_MEAS_PERI_1_M 0x2126 /* measurement: periodic 1 mps, medium repeatability */
#define SHT3X_MEAS_PERI_1_L 0x212D /* measurement: periodic 1 mps, low repeatability */
#define SHT3X_MEAS_PERI_2_H 0x2236 /* measurement: periodic 2 mps, high repeatability */
#define SHT3X_MEAS_PERI_2_M 0x2220 /* measurement: periodic 2 mps, medium repeatability */
#define SHT3X_MEAS_PERI_2_L 0x222B /* measurement: periodic 2 mps, low repeatability */
#define SHT3X_MEAS_PERI_4_H 0x2334 /* measurement: periodic 4 mps, high repeatability */
#define SHT3X_MEAS_PERI_4_M 0x2322 /* measurement: periodic 4 mps, medium repeatability */
#define SHT3X_MEAS_PERI_4_L 0x2329 /* measurement: periodic 4 mps, low repeatability */
#define SHT3X_MEAS_PERI_10_H 0x2737 /* measurement: periodic 10 mps, high repeatability */
#define SHT3X_MEAS_PERI_10_M 0x2721 /* measurement: periodic 10 mps, medium repeatability */
#define SHT3X_MEAS_PERI_10_L 0x272A /* measurement: periodic 10 mps, low repeatability */
#define SHT3X_FETCH_DATA 0xE000 /* readout measurements for periodic mode */
#define SHT3X_R_AL_LIM_LS 0xE102 /* read alert limits, low set */
#define SHT3X_R_AL_LIM_LC 0xE109 /* read alert limits, low clear */
#define SHT3X_R_AL_LIM_HS 0xE11F /* read alert limits, high set */
#define SHT3X_R_AL_LIM_HC 0xE114 /* read alert limits, high clear */
#define SHT3X_W_AL_LIM_HS 0x611D /* write alert limits, high set */
#define SHT3X_W_AL_LIM_HC 0x6116 /* write alert limits, high clear */
#define SHT3X_W_AL_LIM_LC 0x610B /* write alert limits, low clear */
#define SHT3X_W_AL_LIM_LS 0x6100 /* write alert limits, low set */
#define SHT3X_NO_SLEEP 0x303E /* disable sleep */
#define SHT3X_DEFAULT_MEAS_MODE SHT3X_MEAS_PERI_1_H
/****************************************************************************
* Private
****************************************************************************/
struct sht3x_dev_s
{
FAR struct i2c_master_s *i2c; /* I2C interface */
uint8_t addr; /* I2C address */
bool valid; /* If cached readings are valid */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
bool unlinked; /* True, driver has been unlinked */
#endif
struct timespec last_update; /* Last time when sensor was read */
struct sht3x_meas_data_s data; /* Cached sensor values */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
int16_t crefs; /* Number of open references */
#endif
sem_t devsem;
};
struct sht3x_word_s
{
uint8_t data[2];
uint8_t crc;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* I2C Helpers */
static int sht3x_do_transfer(FAR struct i2c_master_s *i2c,
FAR struct i2c_msg_s *msgv,
size_t nmsg);
static int sht3x_write_cmd(FAR struct sht3x_dev_s *priv, uint16_t cmd,
FAR struct sht3x_word_s *params,
unsigned int num_params);
static int sht3x_read_cmd(FAR struct sht3x_dev_s *priv, uint16_t cmd,
FAR struct sht3x_word_s *words,
unsigned int num_words);
/* Character driver methods */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sht3x_open(FAR struct file *filep);
static int sht3x_close(FAR struct file *filep);
#endif
static ssize_t sht3x_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t sht3x_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int sht3x_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sht3x_unlink(FAR struct inode *inode);
#endif
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_sht3xfops =
{
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
sht3x_open, /* open */
sht3x_close, /* close */
#else
NULL, /* open */
NULL, /* close */
#endif
sht3x_read, /* read */
sht3x_write, /* write */
NULL, /* seek */
sht3x_ioctl /* ioctl */
#ifndef CONFIG_DISABLE_POLL
, NULL /* poll */
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, sht3x_unlink /* unlink */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sht3x_do_transfer
****************************************************************************/
static int sht3x_do_transfer(FAR struct i2c_master_s *i2c,
FAR struct i2c_msg_s *msgv,
size_t nmsg)
{
int ret = ret = I2C_TRANSFER(i2c, msgv, nmsg);
if (ret >= 0)
{
return OK;
}
sht3x_dbg("transfer failed: %d\n", ret);
return ret;
}
/****************************************************************************
* Name: sht3x_write_cmd
****************************************************************************/
static int sht3x_write_cmd(FAR struct sht3x_dev_s *priv, uint16_t cmd,
FAR struct sht3x_word_s *params,
unsigned int num_params)
{
struct i2c_msg_s msg[2];
uint8_t cmd_buf[2];
int ret;
cmd_buf[0] = cmd >> 8;
cmd_buf[1] = cmd >> 0;
msg[0].frequency = CONFIG_SHT3X_I2C_FREQUENCY;
msg[0].addr = priv->addr;
msg[0].flags = 0;
msg[0].buffer = cmd_buf;
msg[0].length = 2;
if (num_params)
{
msg[1].frequency = CONFIG_SHT3X_I2C_FREQUENCY;
msg[1].addr = priv->addr;
msg[1].flags = I2C_M_NOSTART;
msg[1].buffer = (FAR uint8_t *)params;
msg[1].length = num_params * sizeof(*params);
}
ret = sht3x_do_transfer(priv->i2c, msg, (num_params) ? 2 : 1);
sht3x_dbg("cmd: 0x%04X num_params: %d ret: %d\n",
cmd, num_params, ret);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: sht3x_read_cmd
****************************************************************************/
static int sht3x_read_cmd(FAR struct sht3x_dev_s *priv, uint16_t cmd,
FAR struct sht3x_word_s *words,
unsigned int num_words)
{
struct i2c_msg_s msg[1];
uint8_t addr_buf[2];
int ret;
addr_buf[0] = cmd >> 8;
addr_buf[1] = cmd >> 0;
msg[0].frequency = CONFIG_SHT3X_I2C_FREQUENCY;
msg[0].addr = priv->addr;
msg[0].flags = 0;
msg[0].buffer = addr_buf;
msg[0].length = 2;
ret = sht3x_do_transfer(priv->i2c, msg, 1);
sht3x_dbg("cmd: 0x%04X ret: %d\n", cmd, ret);
if (ret < 0)
{
return ret;
}
msg[0].frequency = CONFIG_SHT3X_I2C_FREQUENCY;
msg[0].addr = priv->addr;
msg[0].flags = I2C_M_READ;
msg[0].buffer = (FAR uint8_t *)words;
msg[0].length = num_words * sizeof(*words);
ret = sht3x_do_transfer(priv->i2c, msg, 1);
sht3x_dbg("read cmd: 0x%04X num_params: %d ret: %d\n",
cmd, num_words, ret);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: sht3x_crc_word
****************************************************************************/
static uint8_t sht3x_crc_word(uint16_t word)
{
static const uint8_t crc_table[16] =
{
0x00, 0x31, 0x62, 0x53, 0xc4, 0xf5, 0xa6, 0x97,
0xb9, 0x88, 0xdb, 0xea, 0x7d, 0x4c, 0x1f, 0x2e
};
uint8_t crc = 0xff;
crc ^= word >> 8;
crc = (crc << 4) ^ crc_table[crc >> 4];
crc = (crc << 4) ^ crc_table[crc >> 4];
crc ^= word >> 0;
crc = (crc << 4) ^ crc_table[crc >> 4];
crc = (crc << 4) ^ crc_table[crc >> 4];
return crc;
}
/****************************************************************************
* Name: sht3x_data_word2uint16
****************************************************************************/
static uint16_t sht3x_data_word2uint16(FAR const struct sht3x_word_s *word)
{
return (word[0].data[0] << 8) | (word[0].data[1]);
}
/****************************************************************************
* Name: sht3x_check_data_crc
****************************************************************************/
static int sht3x_check_data_crc(FAR const struct sht3x_word_s *words,
unsigned int num_words)
{
while (num_words)
{
if (sht3x_crc_word(sht3x_data_word2uint16(words)) != words->crc)
{
return -1;
}
num_words--;
words++;
}
return 0;
}
/****************************************************************************
* Name: sht3x_softreset
*
* Description:
* Reset the SHT3x sensor.
*
****************************************************************************/
static inline int sht3x_softreset(FAR struct sht3x_dev_s *priv)
{
return sht3x_write_cmd(priv, SHT3X_SOFT_RESET, NULL, 0);
}
/****************************************************************************
* Name: sht3x_temp_to_celsius
*
* Description:
* Convert raw temperature value to degrees Celsius.
*
****************************************************************************/
static inline float sht3x_temp_to_celsius(uint16_t raw)
{
/* Calculate temperature [°C]
* T = -45 + 175 * rawValue / (2^16-1)
*/
return 175.0f * (float)raw / 65535.0f - 45.0f;
}
/****************************************************************************
* Name: sht3x_rh_to_percent
*
* Description:
* Convert raw humidity value to relative humidity [%].
*
****************************************************************************/
static inline float sht3x_rh_to_percent(uint16_t raw)
{
/* Calculate relative humidity [%RH]
* RH = rawValue / (2^16-1) * 100
*/
return 100.0f * (float)raw / 65535.0f;
}
/****************************************************************************
* Name: sht3x_read_values
****************************************************************************/
static int sht3x_read_values(FAR struct sht3x_dev_s *priv,
FAR struct sht3x_meas_data_s *out)
{
struct sht3x_word_s data[2];
uint16_t temp16;
uint16_t rh16;
struct timespec ts;
int ret;
clock_gettime(CLOCK_REALTIME, &ts);
/* Read the raw data */
ret = sht3x_read_cmd(priv, SHT3X_FETCH_DATA, data, 2);
if (ret < 0)
{
sht3x_dbg("ERROR: sht3x_read_cmd failed: %d\n", ret);
return ret;
}
if (sht3x_check_data_crc(data, 2) < 0)
{
sht3x_dbg("ERROR: sht3x_read_values crc failed\n");
ret = -EIO;
return ret;
}
temp16 = sht3x_data_word2uint16(data);
rh16 = sht3x_data_word2uint16(&data[1]);
add_sensor_randomness(ts.tv_nsec ^ ((int)temp16 << 16 | rh16));
priv->data.temperature = sht3x_temp_to_celsius(temp16);
priv->data.humidity = sht3x_rh_to_percent(rh16);
priv->last_update = ts;
priv->valid = true;
*out = priv->data;
return OK;
}
/****************************************************************************
* Name: sht3x_open
*
* Description:
* This function is called whenever the SHT3x device is opened.
*
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sht3x_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sht3x_dev_s *priv = inode->i_private;
int ret;
/* Get exclusive access */
ret = nxsem_wait_uninterruptible(&priv->devsem);
if (ret < 0)
{
return ret;
}
/* Increment the count of open references on the driver */
priv->crefs++;
DEBUGASSERT(priv->crefs > 0);
nxsem_post(&priv->devsem);
return OK;
}
#endif
/****************************************************************************
* Name: sht3x_close
*
* Description:
* This routine is called when the SHT3x device is closed.
*
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sht3x_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sht3x_dev_s *priv = inode->i_private;
int ret;
/* Get exclusive access */
ret = nxsem_wait_uninterruptible(&priv->devsem);
if (ret < 0)
{
return ret;
}
/* Decrement the count of open references on the driver */
DEBUGASSERT(priv->crefs > 0);
priv->crefs--;
/* If the count has decremented to zero and the driver has been unlinked,
* then free memory now.
*/
if (priv->crefs <= 0 && priv->unlinked)
{
nxsem_destroy(&priv->devsem);
kmm_free(priv);
return OK;
}
nxsem_post(&priv->devsem);
return OK;
}
#endif
/****************************************************************************
* Name: sht3x_read
****************************************************************************/
static ssize_t sht3x_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
/* Use ioctl to read from sensor */
return -ENOSYS;
}
/****************************************************************************
* Name: sht3x_write
****************************************************************************/
static ssize_t sht3x_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: sht3x_ioctl
****************************************************************************/
static int sht3x_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sht3x_dev_s *priv = inode->i_private;
int ret;
/* Get exclusive access */
ret = nxsem_wait_uninterruptible(&priv->devsem);
if (ret < 0)
{
return ret;
}
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
if (priv->unlinked)
{
/* Do not allow operations on unlinked sensors. This allows
* sensor use on hot swappable I2C bus.
*/
nxsem_post(&priv->devsem);
return -ENODEV;
}
#endif
switch (cmd)
{
/* Soft reset the SHT3x, Arg: None */
case SNIOC_RESET:
{
ret = sht3x_softreset(priv);
sht3x_dbg("softreset ret: %d\n", ret);
}
break;
/* Start periodic measurement mode, Arg: None */
case SNIOC_START:
{
ret = sht3x_write_cmd(priv, SHT3X_DEFAULT_MEAS_MODE, NULL, 0);
if (ret < 0)
{
sht3x_dbg("cannot start periodic measurement mode: %d\n", ret);
}
}
break;
case SNIOC_READ_CONVERT_DATA:
{
FAR struct sht3x_meas_data_s *data =
(FAR struct sht3x_meas_data_s *)arg;
ret = sht3x_read_values(priv, data);
if (ret < 0)
{
sht3x_dbg("cannot read data: %d\n", ret);
}
}
break;
default:
sht3x_dbg("Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
nxsem_post(&priv->devsem);
return ret;
}
/****************************************************************************
* Name: sht3x_unlink
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sht3x_unlink(FAR struct inode *inode)
{
FAR struct sht3x_dev_s *priv;
int ret;
DEBUGASSERT(inode != NULL && inode->i_private != NULL);
priv = (FAR struct sht3x_dev_s *)inode->i_private;
/* Get exclusive access */
ret = nxsem_wait_uninterruptible(&priv->devsem);
if (ret < 0)
{
return ret;
}
/* Are there open references to the driver data structure? */
if (priv->crefs <= 0)
{
nxsem_destroy(&priv->devsem);
kmm_free(priv);
return OK;
}
/* No... just mark the driver as unlinked and free the resources when
* the last client closes their reference to the driver.
*/
priv->unlinked = true;
nxsem_post(&priv->devsem);
return OK;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sht3x_register
*
* Description:
* Register the SHT3x 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 SHT3x
* addr - The I2C address of the SHT3x.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int sht3x_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
uint8_t addr)
{
FAR struct sht3x_dev_s *priv;
int ret;
DEBUGASSERT(i2c != NULL);
/* Initialize the device structure */
priv = (FAR struct sht3x_dev_s *)kmm_zalloc(sizeof(struct sht3x_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->i2c = i2c;
priv->addr = addr;
nxsem_init(&priv->devsem, 0, 1);
/* Register the character driver */
ret = register_driver(devpath, &g_sht3xfops, 0666, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register driver: %d\n", ret);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_I2C && CONFIG_SENSORS_SHT3X */
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