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incubator-nuttx/drivers/sensors/sgp30.c

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/****************************************************************************
* drivers/sensors/sgp30.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 <stdint.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <time.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/signal.h>
#include <nuttx/fs/fs.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/sensors/sgp30.h>
#include <nuttx/mutex.h>
#include <nuttx/random.h>
#if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_SGP30)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifdef CONFIG_SGP30_DEBUG
# define sgp30_dbg(x, ...) _info(x, ##__VA_ARGS__)
#else
# define sgp30_dbg(x, ...) sninfo(x, ##__VA_ARGS__)
#endif
#ifndef CONFIG_SGP30_I2C_FREQUENCY
# define CONFIG_SGP30_I2C_FREQUENCY 100000
#endif
#define SGP30_I2C_RETRIES 3
#define SGP30_INIT_RETRIES 5
#define SGP30_INIT_LIMIT_MS 10
/****************************************************************************
* Private
****************************************************************************/
struct sgp30_dev_s
{
FAR struct i2c_master_s *i2c; /* I2C interface */
uint8_t addr; /* I2C address */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
bool unlinked; /* True, driver has been unlinked */
#endif
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
int16_t crefs; /* Number of open references */
#endif
struct timespec last_update;
mutex_t devlock;
};
struct sgp30_word_s
{
uint8_t data[2];
uint8_t crc;
};
struct sgp30_cmd_s
{
uint16_t address;
unsigned int read_delay_usec;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* IO Helpers */
static int sgp30_do_transfer(FAR struct i2c_master_s *i2c,
FAR struct i2c_msg_s *msgv,
size_t nmsg);
static int sgp30_write_cmd(FAR struct sgp30_dev_s *priv,
struct sgp30_cmd_s cmd,
FAR struct sgp30_word_s *params,
unsigned int num_params);
static int sgp30_read_cmd(FAR struct sgp30_dev_s *priv,
struct sgp30_cmd_s cmd,
FAR struct sgp30_word_s *words,
unsigned int num_words);
/* Data conversion */
static uint8_t sgp30_crc_word(uint16_t word);
static void sgp30_set_command_param(FAR struct sgp30_word_s *param,
uint16_t value);
static int sgp30_check_data_crc(FAR const struct sgp30_word_s *words,
unsigned int num_words);
static uint16_t sgp30_data_word_to_uint16(
FAR const struct sgp30_word_s *word);
/* Driver features */
static int sgp30_measure_airq(FAR struct sgp30_dev_s *priv,
FAR struct sgp30_conv_data_s *data);
static int sgp30_measure_raw(FAR struct sgp30_dev_s *priv,
FAR struct sgp30_raw_data_s *data);
/* Character driver methods */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sgp30_open(FAR struct file *filep);
static int sgp30_close(FAR struct file *filep);
#endif
static ssize_t sgp30_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t sgp30_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int sgp30_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sgp30_unlink(FAR struct inode *inode);
#endif
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_sgp30fops =
{
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
sgp30_open, /* open */
sgp30_close, /* close */
#else
NULL, /* open */
NULL, /* close */
#endif
sgp30_read, /* read */
sgp30_write, /* write */
NULL, /* seek */
sgp30_ioctl, /* ioctl */
NULL, /* mmap */
NULL, /* truncate */
NULL /* poll */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, sgp30_unlink /* unlink */
#endif
};
/* SGP30 command words */
static const struct sgp30_cmd_s SGP30_CMD_INIT_AIR_QUALITY =
{
0x2003, 0
};
static const struct sgp30_cmd_s SGP30_CMD_MEASURE_AIR_QUALITY =
{
0x2008, 12000
};
static const struct sgp30_cmd_s SGP30_CMD_GET_BASELINE =
{
0x2015, 10000
};
static const struct sgp30_cmd_s SGP30_CMD_SET_BASELINE =
{
0x201e, 10000
};
static const struct sgp30_cmd_s SGP30_CMD_SET_HUMIDITY =
{
0x2061, 10000
};
static const struct sgp30_cmd_s SGP30_CMD_MEASURE_TEST =
{
0x2032, 220000
};
static const struct sgp30_cmd_s SGP30_CMD_GET_FEATURE_SET_VERSION =
{
0x202f, 2000
};
static const struct sgp30_cmd_s SGP30_CMD_MEASURE_RAW_SIGNALS =
{
0x2050, 25000
};
static const struct sgp30_cmd_s SGP30_CMD_GET_SERIAL_ID =
{
0x3682, 500
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sgp30_do_transfer
****************************************************************************/
static int sgp30_do_transfer(FAR struct i2c_master_s *i2c,
FAR struct i2c_msg_s *msgv,
size_t nmsg)
{
int ret = -EIO;
int retries;
for (retries = 0; retries < SGP30_I2C_RETRIES; retries++)
{
ret = I2C_TRANSFER(i2c, msgv, nmsg);
if (ret >= 0)
{
return 0;
}
else
{
/* Some error. Try to reset I2C bus and keep trying. */
#ifdef CONFIG_I2C_RESET
if (retries == SGP30_I2C_RETRIES - 1)
{
break;
}
ret = I2C_RESET(i2c);
if (ret < 0)
{
sgp30_dbg("I2C_RESET failed: %d\n", ret);
return ret;
}
#endif
}
}
sgp30_dbg("xfer failed: %d\n", ret);
return ret;
}
/****************************************************************************
* Name: sgp30_write_cmd
****************************************************************************/
static int sgp30_write_cmd(FAR struct sgp30_dev_s *priv,
struct sgp30_cmd_s cmd,
FAR struct sgp30_word_s *params,
unsigned int num_params)
{
struct i2c_msg_s msg[2];
uint8_t addr_buf[2];
int ret;
addr_buf[0] = cmd.address >> 8;
addr_buf[1] = cmd.address >> 0;
msg[0].frequency = CONFIG_SGP30_I2C_FREQUENCY;
msg[0].addr = priv->addr;
msg[0].flags = 0;
msg[0].buffer = addr_buf;
msg[0].length = 2;
if (num_params)
{
msg[1].frequency = CONFIG_SGP30_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 = sgp30_do_transfer(priv->i2c, msg, (num_params) ? 2 : 1);
sgp30_dbg("cmd: 0x%04X num_params: %d ret: %d\n",
cmd.address, num_params, ret);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: sgp30_read_cmd
****************************************************************************/
static int sgp30_read_cmd(FAR struct sgp30_dev_s *priv,
struct sgp30_cmd_s cmd,
FAR struct sgp30_word_s *words,
unsigned int num_words)
{
struct i2c_msg_s msg[1];
uint8_t addr_buf[2];
int ret;
addr_buf[0] = cmd.address >> 8;
addr_buf[1] = cmd.address >> 0;
msg[0].frequency = CONFIG_SGP30_I2C_FREQUENCY;
msg[0].addr = priv->addr;
msg[0].flags = 0;
msg[0].buffer = addr_buf;
msg[0].length = 2;
ret = sgp30_do_transfer(priv->i2c, msg, 1);
sgp30_dbg("cmd: 0x%04X delay: %uus ret: %d\n", cmd.address,
cmd.read_delay_usec, ret);
if (ret < 0)
{
return ret;
}
up_udelay(cmd.read_delay_usec + 100);
msg[0].frequency = CONFIG_SGP30_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 = sgp30_do_transfer(priv->i2c, msg, 1);
sgp30_dbg("read cmd: 0x%04X num_params: %d ret: %d\n",
cmd.address, num_words, ret);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: sgp30_crc_word
****************************************************************************/
static uint8_t sgp30_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: sgp30_soft_reset
****************************************************************************/
static int sgp30_soft_reset(FAR struct sgp30_dev_s *priv)
{
struct i2c_msg_s msg[1];
uint8_t buf[1];
int ret = 0;
buf[0] = CONFIG_SGP30_RESET_SECOND_BYTE;
msg[0].frequency = CONFIG_SGP30_I2C_FREQUENCY;
msg[0].addr = CONFIG_SGP30_RESET_ADDR;
msg[0].flags = 0;
msg[0].buffer = buf;
msg[0].length = 1;
ret = sgp30_do_transfer(priv->i2c, msg, 1);
return (ret >= 0) ? OK : ret;
}
/****************************************************************************
* Name: sgp30_set_command_param
****************************************************************************/
static void sgp30_set_command_param(FAR struct sgp30_word_s *param,
uint16_t value)
{
param->data[0] = value >> 8;
param->data[1] = value >> 0;
param->crc = sgp30_crc_word(value);
}
/****************************************************************************
* Name: sgp30_data_word_to_uint16
****************************************************************************/
static uint16_t sgp30_data_word_to_uint16(
FAR const struct sgp30_word_s *word)
{
return (word[0].data[0] << 8) | (word[0].data[1]);
}
/****************************************************************************
* Name: sgp30_crc_word
****************************************************************************/
static int sgp30_check_data_crc(FAR const struct sgp30_word_s *words,
unsigned int num_words)
{
while (num_words)
{
if (sgp30_crc_word(sgp30_data_word_to_uint16(words)) != words->crc)
{
return -1;
}
num_words--;
words++;
}
return 0;
}
/****************************************************************************
* Name: has_time_passed
*
* Description:
* Return true if curr >= start + secs_since_start
*
****************************************************************************/
static bool has_time_passed(FAR struct timespec *curr,
FAR 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: time_has_passed_ms
*
* Description:
* Return true if curr >= start + msecs_since_start
*
****************************************************************************/
static bool time_has_passed_ms(FAR struct timespec *curr,
FAR struct timespec *start,
unsigned int msecs_since_start)
{
uint32_t start_msec = start->tv_nsec / (1000 * 1000);
uint32_t curr_msec = curr->tv_nsec / (1000 * 1000);
if (start->tv_sec < curr->tv_sec)
{
curr_msec += 1000 * ((long)(curr->tv_sec - start->tv_sec));
}
return (start_msec + msecs_since_start) <= curr_msec;
}
/****************************************************************************
* Name: sgp30_measure_airq
****************************************************************************/
static int sgp30_measure_airq(FAR struct sgp30_dev_s *priv,
FAR struct sgp30_conv_data_s *data)
{
struct sgp30_word_s words[2];
int ret;
/* Read the data */
ret = sgp30_read_cmd(priv, SGP30_CMD_MEASURE_AIR_QUALITY, words, 2);
if (ret < 0)
{
sgp30_dbg("ERROR: sgp30_write_cmd failed: %d\n", ret);
return ret;
}
if (sgp30_check_data_crc(words, 2) < 0)
{
sgp30_dbg("ERROR: sgp30_read_words crc failed\n");
ret = -EIO;
return ret;
}
add_sensor_randomness(words[0].crc ^ (words[1].crc << 8));
data->co2eq_ppm = sgp30_data_word_to_uint16(words + 0);
data->tvoc_ppb = sgp30_data_word_to_uint16(words + 1);
return OK;
}
/****************************************************************************
* Name: sgp30_measure_raw
****************************************************************************/
static int sgp30_measure_raw(FAR struct sgp30_dev_s *priv,
FAR struct sgp30_raw_data_s *data)
{
struct sgp30_word_s words[2];
int ret;
/* Read the data */
ret = sgp30_read_cmd(priv, SGP30_CMD_MEASURE_RAW_SIGNALS, words, 2);
if (ret < 0)
{
sgp30_dbg("ERROR: sgp30_write_cmd failed: %d\n", ret);
return ret;
}
if (sgp30_check_data_crc(words, 2) < 0)
{
sgp30_dbg("ERROR: sgp30_read_words crc failed\n");
ret = -EIO;
return ret;
}
add_sensor_randomness(words[0].crc ^ (words[1].crc << 8));
data->h2_signal = sgp30_data_word_to_uint16(words + 0);
data->ethanol_signal = sgp30_data_word_to_uint16(words + 1);
return OK;
}
/****************************************************************************
* Name: sgp30_open
*
* Description:
* This function is called whenever the SGP30x device is opened.
*
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sgp30_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sgp30_dev_s *priv = inode->i_private;
int ret = OK;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
/* Increment the count of open references on the driver */
priv->crefs++;
DEBUGASSERT(priv->crefs > 0);
if (priv->crefs == 1)
{
struct sgp30_word_s serial[3];
struct sgp30_word_s buf[1];
if (sgp30_read_cmd(priv, SGP30_CMD_GET_SERIAL_ID, serial, 3) >= 0
&& sgp30_check_data_crc(serial, 3) >= 0 &&
sgp30_read_cmd(priv,
SGP30_CMD_GET_FEATURE_SET_VERSION, buf, 1) >= 0
&& sgp30_check_data_crc(buf, 1) >= 0)
{
struct timespec start;
struct timespec curr;
sgp30_dbg("serial id: %04x-%04x-%04x\n",
sgp30_data_word_to_uint16(serial + 0),
sgp30_data_word_to_uint16(serial + 1),
sgp30_data_word_to_uint16(serial + 2));
sgp30_dbg("feature set version: %d\n",
sgp30_data_word_to_uint16(buf));
add_sensor_randomness((buf[0].crc << 24) ^ (serial[0].crc << 16) ^
(serial[1].crc << 8) ^ (serial[2].crc << 0));
clock_systime_timespec(&start);
ret = sgp30_write_cmd(priv, SGP30_CMD_INIT_AIR_QUALITY, NULL, 0);
if (ret < 0)
{
sgp30_dbg("sgp30_write_cmd(SGP30_CMD_INIT_AIR_QUALITY)"
" failed, %d\n", ret);
}
else
{
uint32_t repeat = SGP30_INIT_RETRIES;
clock_systime_timespec(&curr);
sgp30_dbg("sgp30_write_cmd(SGP30_CMD_INIT_AIR_QUALITY)\n");
while (repeat-- &&
time_has_passed_ms(&curr, &start, SGP30_INIT_LIMIT_MS))
{
/* Infrequently the SGP30_CMD_INIT_AIR_QUALITY message
* delivery takes suspiciously long time
* (SGP30_INIT_LIMIT_MS or more) and in these cases the
* TVOC values will never reach the correct level (not
* even after 24 hours).
* If this delay is detected, the sensor is given a
* "General Call" soft reset as described in the SGP30
* datasheet and initialization is tried again after
* CONFIG_SGP30_RESET_DELAY_US.
*/
ret = sgp30_soft_reset(priv);
if (ret < 0)
{
sgp30_dbg("sgp30_soft_reset failed, %d\n", ret);
return ret;
}
nxsig_usleep(CONFIG_SGP30_RESET_DELAY_US);
clock_systime_timespec(&start);
ret = sgp30_write_cmd(priv, SGP30_CMD_INIT_AIR_QUALITY,
NULL, 0);
clock_systime_timespec(&curr);
if (ret < 0)
{
sgp30_dbg("sgp30_write_cmd(SGP30_CMD_INIT_AIR_QUALITY)"
" failed, %d\n", ret);
}
}
}
}
else
{
ret = -ENODEV;
}
if (ret < 0)
{
ret = -ENODEV;
priv->crefs--;
}
}
nxmutex_unlock(&priv->devlock);
return ret;
}
#endif
/****************************************************************************
* Name: sgp30_close
*
* Description:
* This routine is called when the SGP30 device is closed.
*
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sgp30_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sgp30_dev_s *priv = inode->i_private;
int ret;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
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)
{
nxmutex_destroy(&priv->devlock);
kmm_free(priv);
return OK;
}
nxmutex_unlock(&priv->devlock);
return OK;
}
#endif
/****************************************************************************
* Name: sgp30_read
****************************************************************************/
static ssize_t sgp30_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sgp30_dev_s *priv = inode->i_private;
ssize_t length = 0;
struct timespec ts;
struct timespec ts_sleep;
struct sgp30_conv_data_s data;
int ret;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
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.
*/
nxmutex_unlock(&priv->devlock);
return -ENODEV;
}
#endif
/* Note: For correct operation, SGP30 documentation tells host
* to run measurement command every 1 second.
*/
clock_systime_timespec(&ts);
while (!has_time_passed(&ts, &priv->last_update, 1))
{
if (filep->f_oflags & O_NONBLOCK)
{
nxmutex_unlock(&priv->devlock);
return -EAGAIN;
}
ts_sleep.tv_sec = priv->last_update.tv_sec + 1 - ts.tv_sec;
ts_sleep.tv_nsec = priv->last_update.tv_nsec - ts.tv_nsec;
while (ts_sleep.tv_nsec < 0)
{
ts_sleep.tv_sec--;
ts_sleep.tv_nsec += NSEC_PER_SEC;
}
if ((long)ts_sleep.tv_sec >= 0)
{
ret = nxsig_nanosleep(&ts_sleep, NULL);
if (ret == -EINTR)
{
nxmutex_unlock(&priv->devlock);
return -EINTR;
}
}
clock_systime_timespec(&ts);
}
ret = sgp30_measure_airq(priv, &data);
if (ret < 0)
{
sgp30_dbg("cannot read data: %d\n", ret);
}
else
{
/* This interface is mainly intended for easy debugging in nsh. */
length = snprintf(buffer, buflen, "%u %u\n",
data.co2eq_ppm, data.tvoc_ppb);
if (length > buflen)
{
length = buflen;
}
priv->last_update = ts;
}
nxmutex_unlock(&priv->devlock);
return length;
}
/****************************************************************************
* Name: sgp30_write
****************************************************************************/
static ssize_t sgp30_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
return -ENOSYS;
}
/****************************************************************************
* Name: sgp30_ioctl
****************************************************************************/
static int sgp30_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct sgp30_dev_s *priv = inode->i_private;
struct sgp30_word_s buf[2];
int ret;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
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.
*/
nxmutex_unlock(&priv->devlock);
return -ENODEV;
}
#endif
switch (cmd)
{
/* Soft reset the SGP30, Arg: None */
case SNIOC_RESET:
{
/* Note: After INIT_AIR_QUALITY, host should write baseline
* values (SNIOC_SET_BASELINE) from non-volatile memory if
* stored values are less than week old. Without baseline
* values, sensor enters 12hr long early operation phase.
*/
ret = sgp30_write_cmd(priv, SGP30_CMD_INIT_AIR_QUALITY, NULL, 0);
sgp30_dbg("reset ret: %d\n", ret);
}
break;
/* Get sensor baseline, Arg: struct sgp30_baseline_s * */
case SNIOC_GET_BASELINE:
{
FAR struct sgp30_baseline_s *baseline =
(FAR struct sgp30_baseline_s *)arg;
/* Note: SGP30 documentation tells host should read baseline values
* every 1 hour and save to non-volatile memory along with
* timestamp.
*/
ret = sgp30_read_cmd(priv, SGP30_CMD_GET_BASELINE, buf, 2);
if (ret >= 0)
{
if (sgp30_check_data_crc(buf, 2) < 0)
{
ret = -EIO;
break;
}
baseline->co2eq_baseline = sgp30_data_word_to_uint16(buf + 0);
baseline->tvoc_baseline = sgp30_data_word_to_uint16(buf + 1);
}
}
break;
/* Set sensor baseline, Arg: struct sgp30_baseline_s * */
case SNIOC_SET_BASELINE:
{
FAR const struct sgp30_baseline_s *baseline =
(FAR const struct sgp30_baseline_s *)arg;
sgp30_set_command_param(buf + 0, baseline->co2eq_baseline);
sgp30_set_command_param(buf + 1, baseline->tvoc_baseline);
ret = sgp30_write_cmd(priv, SGP30_CMD_SET_BASELINE, buf, 2);
}
break;
/* Set humidity compensation value, Arg: uint16_t */
case SNIOC_SET_HUMIDITY:
{
/* Input is absolute humidity in unit "mg/m^3". */
if (arg >= 256000)
{
ret = -EINVAL;
break;
}
arg = arg * 256 / 1000; /* scale to range 0..65535 */
sgp30_set_command_param(buf, arg);
ret = sgp30_write_cmd(priv, SGP30_CMD_SET_HUMIDITY, buf, 1);
}
break;
/* Read sensor data, Arg: struct sgp30_conv_data_s *data */
case SNIOC_READ_CONVERT_DATA:
{
FAR struct sgp30_conv_data_s *data =
(FAR struct sgp30_conv_data_s *)arg;
/* Note: For correct operation, SGP30 documentation tells host
* to run measurement command every 1 second.
*/
ret = sgp30_measure_airq(priv, data);
if (ret < 0)
{
sgp30_dbg("cannot read data: %d\n", ret);
}
}
break;
/* Read raw data, Arg: struct sgp30_raw_data_s *data */
case SNIOC_READ_RAW_DATA:
{
FAR struct sgp30_raw_data_s *data =
(FAR struct sgp30_raw_data_s *)arg;
ret = sgp30_measure_raw(priv, data);
if (ret < 0)
{
sgp30_dbg("cannot read data: %d\n", ret);
}
}
break;
/* Run selftest, Arg: None. */
case SNIOC_START_SELFTEST:
{
ret = sgp30_write_cmd(priv, SGP30_CMD_MEASURE_TEST, NULL, 0);
if (ret >= 0)
{
if (sgp30_check_data_crc(buf, 1) < 0)
{
sgp30_dbg("crc error\n");
ret = -EIO;
}
else if (sgp30_data_word_to_uint16(buf) != 0xd400)
{
sgp30_dbg("self-test failed, 0x%04x\n",
sgp30_data_word_to_uint16(buf));
ret = -EFAULT;
}
}
}
break;
default:
sgp30_dbg("Unrecognized cmd: %d\n", cmd);
ret = -ENOTTY;
break;
}
nxmutex_unlock(&priv->devlock);
return ret;
}
/****************************************************************************
* Name: sgp30_unlink
****************************************************************************/
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
static int sgp30_unlink(FAR struct inode *inode)
{
FAR struct sgp30_dev_s *priv;
int ret;
DEBUGASSERT(inode->i_private != NULL);
priv = inode->i_private;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
/* Are there open references to the driver data structure? */
if (priv->crefs <= 0)
{
nxmutex_destroy(&priv->devlock);
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;
nxmutex_unlock(&priv->devlock);
return OK;
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sgp30_register
*
* Description:
* Register the SGP30 character device as 'devpath'
*
* Input Parameters:
* devpath - The full path to the driver to register. E.g., "/dev/gas0"
* i2c - An instance of the I2C interface to use to communicate with
* the SGP30
* addr - The I2C address of the SGP30. The I2C address of SGP30 is
* always 0x58.
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int sgp30_register(FAR const char *devpath, FAR struct i2c_master_s *i2c,
uint8_t addr)
{
FAR struct sgp30_dev_s *priv;
int ret;
DEBUGASSERT(i2c != NULL);
DEBUGASSERT(addr == CONFIG_SGP30_ADDR);
DEBUGASSERT(sgp30_crc_word(0xbeef) == 0x92);
/* Initialize the device structure */
priv = kmm_zalloc(sizeof(struct sgp30_dev_s));
if (priv == NULL)
{
sgp30_dbg("ERROR: Failed to allocate instance\n");
return -ENOMEM;
}
priv->i2c = i2c;
priv->addr = addr;
nxmutex_init(&priv->devlock);
/* Register the character driver */
ret = register_driver(devpath, &g_sgp30fops, 0666, priv);
if (ret < 0)
{
sgp30_dbg("ERROR: Failed to register driver: %d\n", ret);
nxmutex_destroy(&priv->devlock);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_I2C && CONFIG_SENSORS_SGP30 */
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