/**************************************************************************** * drivers/sensors/aht10.c * Driver for the ASAIR AHT10 temperature and humidity sensors * * Copyright (C) 2019 Gregory Nutt. All rights reserved. * Author: kyChu * * 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 #if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_AHT10) /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #ifndef CONFIG_AHT10_I2C_FREQUENCY # define CONFIG_AHT10_I2C_FREQUENCY 400000 #endif /* I2C command bytes */ #define AHT10_SOFT_INIT 0xe1 #define AHT10_MEAS_TRIG 0xac #define AHT10_MEAS_READ 0x71 #define AHT10_NORMAL_CMD 0xa8 /**************************************************************************** * Private ****************************************************************************/ struct aht10_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 int temperature; /* Cached temperature */ int humidity; /* Cached humidity */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS int16_t crefs; /* Number of open references */ #endif sem_t devsem; }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* I2C Helpers */ static int aht10_writereg(FAR struct aht10_dev_s *priv, uint8_t reg, FAR uint8_t *data); static int aht10_readregs(FAR struct aht10_dev_s *priv, FAR uint8_t *buf, uint8_t len); /* Character driver methods */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS static int aht10_open(FAR struct file *filep); static int aht10_close(FAR struct file *filep); #endif static ssize_t aht10_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t aht10_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int aht10_ioctl(FAR struct file *filep, int cmd, unsigned long arg); #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS static int aht10_unlink(FAR struct inode *inode); #endif /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_aht10fops = { #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS aht10_open, /* open */ aht10_close, /* close */ #else NULL, /* open */ NULL, /* close */ #endif aht10_read, /* read */ aht10_write, /* write */ NULL, /* seek */ aht10_ioctl, /* ioctl */ NULL /* poll */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , aht10_unlink /* unlink */ #endif }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: aht10_writereg * * Description: * I2C write access helper. * ****************************************************************************/ static int aht10_writereg(FAR struct aht10_dev_s *priv, uint8_t reg, FAR uint8_t *data) { struct i2c_msg_s msg; uint8_t buf[3]; int ret; buf[0] = reg; buf[1] = data[0]; buf[2] = data[1]; msg.frequency = CONFIG_AHT10_I2C_FREQUENCY; msg.addr = priv->addr; msg.flags = 0; msg.buffer = buf; msg.length = 3; ret = I2C_TRANSFER(priv->i2c, &msg, 1); return (ret >= 0) ? OK : ret; } /**************************************************************************** * Name: aht10_readregs * * Description: * I2C read access helper. * ****************************************************************************/ static int aht10_readregs(FAR struct aht10_dev_s *priv, FAR uint8_t *buf, uint8_t len) { struct i2c_msg_s msg; int ret; msg.frequency = CONFIG_AHT10_I2C_FREQUENCY; msg.addr = priv->addr; msg.flags = I2C_M_READ; msg.buffer = buf; msg.length = len; ret = I2C_TRANSFER(priv->i2c, &msg, 1); return (ret >= 0) ? OK : ret; } /**************************************************************************** * Name: aht10_initialize * * Description: * Initialize the AHT10 sensor. This takes less than 20 ms. * ****************************************************************************/ static int aht10_initialize(FAR struct aht10_dev_s *priv) { int ret; uint8_t buf[2]; buf[0] = 0x00; buf[1] = 0x00; ret = aht10_writereg(priv, AHT10_NORMAL_CMD, buf); if (ret < 0) { snerr("ERROR: write normal command failed: %d\n", ret); return ret; } /* wait at least 300ms */ nxsig_usleep(300000); buf[0] = 0x08; buf[1] = 0x00; ret = aht10_writereg(priv, AHT10_SOFT_INIT, buf); if (ret < 0) { snerr("ERROR: send calibrate command failed: %d\n", ret); return ret; } /* wait at least 300ms */ nxsig_usleep(300000); return ret; } /**************************************************************************** * Name: aht10_temp_to_mcelsius * * Description: * Convert raw temperature value to milli celsius. * ****************************************************************************/ static inline int aht10_temp_to_mcelsius(uint32_t raw) { /* Formula T = -50 + 200 * (ST / 2^20) from datasheet, * converted to integer fixed point (3 digits) representation. */ return ((raw * 3125) >> 14) - 50000; } /**************************************************************************** * Name: aht10_rh_to_pcm * * Description: * Convert raw humidity value to one-thousandths of a percent * (per cent mille) relative humidity. * ****************************************************************************/ static inline int aht10_rh_to_pcm(uint32_t raw) { /* Formula RH = (SRH / 2^20) * 100% from datasheet, * converted to integer fixed point (3 digits) representation. */ return (raw >> 15) * 3125; } /**************************************************************************** * Name: aht10_read_values * * Description: read raw data from the sensor. * ****************************************************************************/ static int aht10_read_values(FAR struct aht10_dev_s *priv, FAR int *temp, FAR int *rh) { uint8_t buf[6]; uint32_t temp20; uint32_t rh20; int ret; /* Sample command */ buf[0] = 0x33; buf[1] = 0x00; ret = aht10_writereg(priv, AHT10_MEAS_TRIG, buf); if (ret < 0) { snerr("ERROR: aht10_writereg failed: %d\n", ret); return ret; } /* Read the raw temperature data and humidity data */ ret = aht10_readregs(priv, buf, 6); if (ret < 0) { snerr("ERROR: aht10_readregs failed: %d\n", ret); return ret; } /* Check the AHT10 has been calibrated. */ if ((buf[0] & 0x68) != 0x08) { aht10_initialize(priv); snwarn("WARNING: aht10 are not calibrated.\n"); } /* Humidity data (20bits). */ rh20 = ((buf[1] << 12) | (buf[2] << 4) | ((buf[3] & 0xf0) >> 4)) & 0x000fffff; /* Temperature data (20bits). */ temp20 = (((buf[3] & 0x0f) << 16) | (buf[4] << 8) | buf[5]) & 0x000fffff; add_sensor_randomness((int)temp20 << 16 | rh20); /* Sensor data convert to reality */ priv->temperature = aht10_temp_to_mcelsius(temp20); priv->humidity = aht10_rh_to_pcm(rh20); *temp = priv->temperature; *rh = priv->humidity; return OK; } /**************************************************************************** * Name: aht10_open * * Description: * This function is called whenever the AHT10 device is opened. * ****************************************************************************/ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS static int aht10_open(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct aht10_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); nxsem_post(&priv->devsem); return OK; } #endif /**************************************************************************** * Name: aht10_close * * Description: * This routine is called when the SHT2x device is closed. * ****************************************************************************/ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS static int aht10_close(FAR struct file *filep) { FAR struct inode *inode = filep->f_inode; FAR struct aht10_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: aht10_read ****************************************************************************/ static ssize_t aht10_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { FAR struct inode *inode = filep->f_inode; FAR struct aht10_dev_s *priv = inode->i_private; ssize_t length = 0; int temp; int rh; 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 ret = aht10_read_values(priv, &temp, &rh); if (ret < 0) { sninfo("cannot read data: %d\n", ret); } else { /* This interface is mainly intended for easy debugging in nsh. */ length = snprintf(buffer, buflen, "%d %d\n", temp, rh); if (length > buflen) { length = buflen; } } nxsem_post(&priv->devsem); return length; } /**************************************************************************** * Name: aht10_write ****************************************************************************/ static ssize_t aht10_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return -ENOSYS; } /**************************************************************************** * Name: aht10_ioctl ****************************************************************************/ static int aht10_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode = filep->f_inode; FAR struct aht10_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); #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 AHT10, Arg: None */ case SNIOC_RESET: { ret = aht10_initialize(priv); sninfo("softreset ret: %d\n", ret); } break; case SNIOC_READ_RAW_DATA: case SNIOC_READ_CONVERT_DATA: { int temp; int rh; ret = aht10_read_values(priv, &temp, &rh); if (ret < 0) { sninfo("cannot read data: %d\n", ret); } else { FAR struct aht10_conv_data_s *data = (FAR struct aht10_conv_data_s *)arg; data->temperature = temp; data->humidity = rh; } } break; default: sninfo("Unrecognized cmd: %d\n", cmd); ret = -ENOTTY; break; } nxsem_post(&priv->devsem); return ret; } /**************************************************************************** * Name: aht10_unlink ****************************************************************************/ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS static int aht10_unlink(FAR struct inode *inode) { FAR struct aht10_dev_s *priv; int ret; DEBUGASSERT(inode != NULL && inode->i_private != NULL); priv = (FAR struct aht10_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: aht10_register * * Description: * Register the AHT10 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 AHT10 * addr - The I2C address of the AHT10 (always 0x38). * * Returned Value: * Zero (OK) on success; a negated errno value on failure. * ****************************************************************************/ int aht10_register(FAR const char *devpath, FAR struct i2c_master_s *i2c, uint8_t addr) { FAR struct aht10_dev_s *priv; int ret; DEBUGASSERT(i2c != NULL); DEBUGASSERT(addr == CONFIG_AHT10_ADDR); /* Initialize the device structure */ priv = (FAR struct aht10_dev_s *)kmm_zalloc(sizeof(struct aht10_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); ret = aht10_initialize(priv); if (ret < 0) { snerr("ERROR: Failed to initialize AHT10: %d\n", ret); kmm_free(priv); return ret; } /* Register the character driver */ ret = register_driver(devpath, &g_aht10fops, 0666, priv); if (ret < 0) { snerr("ERROR: Failed to register driver: %d\n", ret); kmm_free(priv); } return ret; } #endif /* CONFIG_I2C && CONFIG_SENSORS_AHT10 */