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incubator-nuttx/drivers/sensors/aht10.c

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/****************************************************************************
* drivers/sensors/aht10.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 <stdio.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/mutex.h>
#include <nuttx/fs/fs.h>
#include <nuttx/i2c/i2c_master.h>
#include <nuttx/sensors/aht10.h>
#include <nuttx/random.h>
#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
mutex_t devlock;
};
/****************************************************************************
* 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, /* mmap */
NULL, /* truncate */
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;
/* Get exclusive access */
nxmutex_lock(&priv->devlock);
/* Increment the count of open references on the driver */
priv->crefs++;
DEBUGASSERT(priv->crefs > 0);
nxmutex_unlock(&priv->devlock);
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;
/* Get exclusive access */
nxmutex_lock(&priv->devlock);
/* 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: 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 */
nxmutex_lock(&priv->devlock);
#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
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;
}
}
nxmutex_unlock(&priv->devlock);
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 */
nxmutex_lock(&priv->devlock);
#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 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;
}
nxmutex_unlock(&priv->devlock);
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->i_private != NULL);
priv = inode->i_private;
/* Get exclusive access */
nxmutex_lock(&priv->devlock);
/* 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 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 = 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;
nxmutex_init(&priv->devlock);
ret = aht10_initialize(priv);
if (ret < 0)
{
snerr("ERROR: Failed to initialize AHT10: %d\n", ret);
nxmutex_destroy(&priv->devlock);
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);
nxmutex_destroy(&priv->devlock);
kmm_free(priv);
}
return ret;
}
#endif /* CONFIG_I2C && CONFIG_SENSORS_AHT10 */
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