/**************************************************************************** * drivers/sensors/sgp30.c * Driver for the Sensirion SGP30 Gas Platform sensor * * Copyright (C) 2019 Haltian Ltd. All rights reserved. * Author: Jussi Kivilinna * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #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 /**************************************************************************** * 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; sem_t devsem; }; 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 */ #ifndef CONFIG_DISABLE_POLL , NULL /* poll */ #endif #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_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(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: 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; /* Get exclusive access */ do { ret = nxsem_wait(&priv->devsem); /* The only case that an error should occur here is if the wait was * awakened by a signal. */ DEBUGASSERT(ret == OK || ret == -EINTR); } while (ret == -EINTR); /* 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) { 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)); 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 { ret = -ENODEV; } if (ret < 0) { ret = -ENODEV; priv->crefs--; } } nxsem_post(&priv->devsem); 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 */ do { ret = nxsem_wait(&priv->devsem); /* The only case that an error should occur here is if the wait was * awakened by a signal. */ DEBUGASSERT(ret == OK || ret == -EINTR); } while (ret == -EINTR); /* 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: 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, ts_sleep; struct sgp30_conv_data_s data; int ret; /* Get exclusive access */ do { ret = nxsem_wait(&priv->devsem); /* The only case that an error should occur here is if the wait was * awakened by a signal. */ DEBUGASSERT(ret == OK || ret == -EINTR); } while (ret == -EINTR); #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 /* Note: For correct operation, SGP30 documentation tells host * to run measurement command every 1 second. */ clock_gettime(CLOCK_REALTIME, &ts); while (!has_time_passed(ts, priv->last_update, 1)) { if (filep->f_oflags & O_NONBLOCK) { nxsem_post(&priv->devsem); 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) { nxsem_post(&priv->devsem); return -EINTR; } } clock_gettime(CLOCK_REALTIME, &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; } nxsem_post(&priv->devsem); 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 */ do { ret = nxsem_wait(&priv->devsem); /* The only case that an error should occur here is if the wait was * awakened by a signal. */ DEBUGASSERT(ret == OK || ret == -EINTR); } while (ret == -EINTR); #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 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 < 0 || 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; } nxsem_post(&priv->devsem); 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 != NULL && inode->i_private != NULL); priv = (FAR struct sgp30_dev_s *)inode->i_private; /* Get exclusive access */ do { ret = nxsem_wait(&priv->devsem); /* The only case that an error should occur here is if the wait was * awakened by a signal. */ DEBUGASSERT(ret == OK || ret == -EINTR); } while (ret == -EINTR); /* 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 ret; } #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 = (FAR struct sgp30_dev_s *)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; nxsem_init(&priv->devsem, 0, 1); /* 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); kmm_free(priv); } return ret; } #endif /* CONFIG_I2C && CONFIG_SENSORS_SGP30 */