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RIOT/drivers/sht3x/sht3x_saul.c
Marian Buschsieweke 16f859dafd
drivers/saul: use const qualifier for data to write
This makes life easier when calling e.g. `saul_reg_write()` with data
stored in flash.

As now the signatures for reading and writing differ (in that `const`
qualifier only), `saul_notsup()` is split into `saul_write_notsup()`
and `saul_read_notsup()`. However, one is implemented as a symbol alias
of the other, so that ROM consumption remains unchanged.
2022-05-23 08:35:27 +02:00

122 lines
3.2 KiB
C

/*
* Copyright (C) 2018 Gunar Schorcht
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup drivers_sht3x
* @brief SAUL adaption for Sensirion SHT30/SHT31/SHT35 devices
* @author Gunar Schorcht <gunar@schorcht.net>
* @file
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include "phydat.h"
#include "saul.h"
#include "sht3x.h"
#include "sht3x_params.h"
#define SHT3X_NUM ARRAY_SIZE(sht3x_params)
extern sht3x_dev_t sht3x_devs[SHT3X_NUM];
/**
* Humidity and temperature sensor values are fetched by separate saul
* functions. To avoid double waiting for the sensor and readout of the
* sensor values, we read both sensor values once, if necessary, and
* store them in local variables to provide them in the separate saul
* read functions.
*/
static bool _temp_valid[SHT3X_NUM] = { false };
static bool _hum_valid[SHT3X_NUM] = { false };
static int16_t _temp[SHT3X_NUM];
static int16_t _hum[SHT3X_NUM];
static unsigned _dev2index (const sht3x_dev_t *dev)
{
/*
* returns the index of the device in sht3x_devs[] or SHT3_NUM
* if not found
*/
for (unsigned i = 0; i < SHT3X_NUM; i++) {
if (dev == &sht3x_devs[i]) {
return i;
}
}
return SHT3X_NUM;
}
static int _read(int dev)
{
/* read both sensor values */
unsigned res = sht3x_read(&sht3x_devs[dev], &_temp[dev], &_hum[dev]);
if (res != SHT3X_OK) {
return res;
}
/* mark both sensor values as valid */
_temp_valid[dev] = true;
_hum_valid[dev] = true;
return SHT3X_OK;
}
static int read_temp(const void *dev, phydat_t *data)
{
/* find the device index */
unsigned dev_index = _dev2index((const sht3x_dev_t *)dev);
if (dev_index == SHT3X_NUM) {
/* return with error if device index could not be found */
return -ECANCELED;
}
/* either local variable is valid or fetching it was successful */
if (_temp_valid[dev_index] || _read(dev_index) == SHT3X_OK) {
/* mark local variable as invalid */
_temp_valid[dev_index] = false;
data->val[0] = _temp[dev_index];
data->unit = UNIT_TEMP_C;
data->scale = -2;
return 1;
}
return -ECANCELED;
}
static int read_hum(const void *dev, phydat_t *data)
{
/* find the device index */
unsigned dev_index = _dev2index((const sht3x_dev_t *)dev);
if (dev_index == SHT3X_NUM) {
/* return with error if device index could not be found */
return -ECANCELED;
}
/* either local variable is valid or fetching it was successful */
if (_hum_valid[dev_index] || _read(dev_index) == SHT3X_OK) {
/* mark local variable as invalid */
_hum_valid[dev_index] = false;
data->val[0] = _hum[dev_index];
data->unit = UNIT_PERCENT;
data->scale = -2;
return 1;
}
return -ECANCELED;
}
const saul_driver_t sht3x_saul_driver_temperature = {
.read = read_temp,
.write = saul_write_notsup,
.type = SAUL_SENSE_TEMP
};
const saul_driver_t sht3x_saul_driver_humidity = {
.read = read_hum,
.write = saul_write_notsup,
.type = SAUL_SENSE_HUM
};