sensors: dht: move dht to own directory under drivers/sensor/
Change-Id: Id19b4ea414347caa23730e3ccd4f79761878af01 Signed-off-by: Anas Nashif <anas.nashif@intel.com>
This commit is contained in:
Anas Nashif
Anas Nashif
parent
49a6d13849
commit
9078ad7982
6 changed files with 5 additions and 4 deletions
72
drivers/sensor/dht/Kconfig
Normal file
72
drivers/sensor/dht/Kconfig
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@ -0,0 +1,72 @@
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# Kconfig - DHT Temperature and Himidity Sensor configuration options
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#
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# Copyright (c) 2016 Intel Corporation
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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menuconfig DHT
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bool
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prompt "DHT Temperature and Humidity Sensor"
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depends on SENSOR && GPIO
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default n
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help
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Enable driver for the DHT temperature and humidity sensor family.
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choice
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prompt "Chip type"
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depends on DHT
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default DHT_CHIP_DHT11
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help
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Choose desired chip type from the DHT family.
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config DHT_CHIP_DHT11
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bool
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prompt "DHT11"
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help
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Choose this option to enable the DHT11 chip.
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config DHT_CHIP_DHT22
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bool
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prompt "DHT22"
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help
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Choose this option to enable the DHT22 chip.
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endchoice
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config DHT_NAME
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string
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prompt "Driver name"
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default "DHT11" if DHT_CHIP_DHT11
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default "DHT22" if DHT_CHIP_DHT22
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depends on DHT
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help
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Device name with which the sensor is identified.
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config DHT_GPIO_DEV_NAME
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string
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prompt "GPIO device"
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default "GPIO_0"
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depends on DHT
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help
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The device name of the GPIO device to which the chip's data pin
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is connected.
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config DHT_GPIO_PIN_NUM
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int
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prompt "Interrupt GPIO pin number"
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default 0
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depends on DHT
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help
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The number of the GPIO on which the chip's data pin is connected.
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1
drivers/sensor/dht/Makefile
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1
drivers/sensor/dht/Makefile
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@ -0,0 +1 @@
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obj-$(CONFIG_DHT) += dht.o
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248
drivers/sensor/dht/dht.c
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248
drivers/sensor/dht/dht.c
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@ -0,0 +1,248 @@
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/*
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* Copyright (c) 2016 Intel Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <device.h>
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#include <gpio.h>
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#include <misc/byteorder.h>
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#include <misc/util.h>
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#include <sensor.h>
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#include <string.h>
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#include <zephyr.h>
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#include "dht.h"
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/**
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* @brief Measure duration of signal send by sensor
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*
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* @param drv_data Pointer to the driver data structure
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* @param singnal_val Value of signal being measured
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*
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* @return duration in usec of signal being measured,
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* -1 if duration exceeds DHT_SIGNAL_MAX_WAIT_DURATION
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*/
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static int8_t dht_measure_signal_duration(struct dht_data *drv_data,
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uint32_t signal_val)
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{
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uint32_t val;
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uint32_t elapsed_cycles;
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uint32_t max_wait_cycles = (uint32_t)(
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(uint64_t)DHT_SIGNAL_MAX_WAIT_DURATION *
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(uint64_t)sys_clock_hw_cycles_per_sec /
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(uint64_t)USEC_PER_SEC
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);
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uint32_t start_cycles = sys_cycle_get_32();
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do {
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gpio_pin_read(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM, &val);
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elapsed_cycles = sys_cycle_get_32() - start_cycles;
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if (elapsed_cycles >= max_wait_cycles) {
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return -1;
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}
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} while (val == signal_val);
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return (uint64_t)elapsed_cycles *
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(uint64_t)USEC_PER_SEC /
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(uint64_t)sys_clock_hw_cycles_per_sec;
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}
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static int dht_sample_fetch(struct device *dev, enum sensor_channel chan)
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{
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struct dht_data *drv_data = dev->driver_data;
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int ret = 0;
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int8_t signal_duration[DHT_DATA_BITS_NUM];
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int8_t max_duration, min_duration, avg_duration;
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uint8_t buf[5];
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unsigned int i, j;
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
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/* send start signal */
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gpio_pin_write(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM, 0);
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sys_thread_busy_wait(DHT_START_SIGNAL_DURATION);
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gpio_pin_write(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM, 1);
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/* switch to DIR_IN to read sensor signals */
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gpio_pin_configure(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM,
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GPIO_DIR_IN);
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/* wait for sensor response */
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if (dht_measure_signal_duration(drv_data, 1) == -1) {
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ret = -EIO;
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goto cleanup;
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}
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/* read sensor response */
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if (dht_measure_signal_duration(drv_data, 0) == -1) {
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ret = -EIO;
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goto cleanup;
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}
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/* wait for sensor data */
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if (dht_measure_signal_duration(drv_data, 1) == -1) {
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ret = -EIO;
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goto cleanup;
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}
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/* read sensor data */
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for (i = 0; i < DHT_DATA_BITS_NUM; i++) {
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/* LOW signal to indicate a new bit */
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if (dht_measure_signal_duration(drv_data, 0) == -1) {
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ret = -EIO;
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goto cleanup;
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}
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/* HIGH signal duration indicates bit value */
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signal_duration[i] = dht_measure_signal_duration(drv_data, 1);
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if (signal_duration[i] == -1) {
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ret = -EIO;
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goto cleanup;
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}
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}
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/*
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* the datasheet says 20-40us HIGH signal duration for a 0 bit and
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* 80us for a 1 bit; however, since dht_measure_signal_duration is
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* not very precise, compute the threshold for deciding between a
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* 0 bit and a 1 bit as the average between the minimum and maximum
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* if the durations stored in signal_duration
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*/
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min_duration = signal_duration[0];
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max_duration = signal_duration[0];
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for (i = 1; i < DHT_DATA_BITS_NUM; i++) {
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if (min_duration > signal_duration[i]) {
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min_duration = signal_duration[i];
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}
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if (max_duration < signal_duration[i]) {
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max_duration = signal_duration[i];
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}
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}
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avg_duration = ((int16_t)min_duration + (int16_t)max_duration) / 2;
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/* store bits in buf */
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j = 0;
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memset(buf, 0, sizeof(buf));
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for (i = 0; i < DHT_DATA_BITS_NUM; i++) {
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if (signal_duration[i] >= avg_duration) {
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buf[j] = (buf[j] << 1) | 1;
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} else {
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buf[j] = buf[j] << 1;
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}
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if (i % 8 == 7) {
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j++;
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}
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}
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/* verify checksum */
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if (((buf[0] + buf[1] + buf[2] + buf[3]) & 0xFF) != buf[4]) {
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SYS_LOG_DBG("Invalid checksum in fetched sample");
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ret = -EIO;
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} else {
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memcpy(drv_data->sample, buf, 4);
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}
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cleanup:
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/* switch to DIR_OUT and leave pin to HIGH until next fetch */
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gpio_pin_configure(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM,
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GPIO_DIR_OUT);
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gpio_pin_write(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM, 1);
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return ret;
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}
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static int dht_channel_get(struct device *dev,
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enum sensor_channel chan,
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struct sensor_value *val)
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{
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struct dht_data *drv_data = dev->driver_data;
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__ASSERT_NO_MSG(chan == SENSOR_CHAN_TEMP || chan == SENSOR_CHAN_HUMIDITY);
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val->type = SENSOR_VALUE_TYPE_INT_PLUS_MICRO;
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/* see data calculation example from datasheet */
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#if defined(CONFIG_DHT_CHIP_DHT11)
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/* use only integral data byte */
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if (chan == SENSOR_CHAN_HUMIDITY) {
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val->val1 = drv_data->sample[0] * 1000;
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val->val2 = 0;
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} else { /* chan == SENSOR_CHAN_TEMP */
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val->val1 = drv_data->sample[2];
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val->val2 = 0;
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}
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#elif defined(CONFIG_DHT_CHIP_DHT22)
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/*
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* use both integral and decimal data bytes; resulted 16bit data has
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* a resolution of 0.1 units
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*/
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int16_t raw_val, sign;
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if (chan == SENSOR_CHAN_HUMIDITY) {
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raw_val = (drv_data->sample[0] << 8) | drv_data->sample[1];
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val->val1 = raw_val * 100;
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val->val2 = 0;
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} else { /* chan == SENSOR_CHAN_TEMP */
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raw_val = (drv_data->sample[2] << 8) | drv_data->sample[3];
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sign = raw_val & 0x8000;
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raw_val = raw_val & ~0x8000;
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val->val1 = raw_val / 10;
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val->val2 = (raw_val % 10) * 100000;
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/* handle negative value */
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if (sign) {
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val->val1 = -val->val1;
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val->val2 = -val->val2;
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}
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}
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#endif
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return 0;
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}
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static struct sensor_driver_api dht_api = {
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.sample_fetch = &dht_sample_fetch,
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.channel_get = &dht_channel_get,
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};
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static int dht_init(struct device *dev)
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{
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struct dht_data *drv_data = dev->driver_data;
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drv_data->gpio = device_get_binding(CONFIG_DHT_GPIO_DEV_NAME);
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if (drv_data->gpio == NULL) {
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SYS_LOG_ERR("Failed to get GPIO device.");
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return -EINVAL;
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}
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gpio_pin_configure(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM,
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GPIO_DIR_OUT);
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gpio_pin_write(drv_data->gpio, CONFIG_DHT_GPIO_PIN_NUM, 1);
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dev->driver_api = &dht_api;
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return 0;
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}
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struct dht_data dht_data;
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DEVICE_INIT(dht_dev, CONFIG_DHT_NAME, &dht_init, &dht_data,
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NULL, SECONDARY, CONFIG_SENSOR_INIT_PRIORITY);
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35
drivers/sensor/dht/dht.h
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35
drivers/sensor/dht/dht.h
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@ -0,0 +1,35 @@
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/*
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* Copyright (c) 2016 Intel Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef _SENSOR_DHT
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#define _SENSOR_DHT
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#include <device.h>
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#define SYS_LOG_DOMAIN "DHT"
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#define SYS_LOG_LEVEL CONFIG_SYS_LOG_SENSOR_LEVEL
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#include <misc/sys_log.h>
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#define DHT_START_SIGNAL_DURATION 18000
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#define DHT_SIGNAL_MAX_WAIT_DURATION 100
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#define DHT_DATA_BITS_NUM 40
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struct dht_data {
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struct device *gpio;
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uint8_t sample[4];
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};
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#endif
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