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RIOT/drivers/dht/dht_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

65 lines
1.5 KiB
C

/*
* Copyright (C) 2016 Freie Universität Berlin
*
* 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_dht
* @{
*
* @file
* @brief SAUL adaption for DHT devices
*
* The values exported to SAUL for DHT devices are buffered, meaning that new
* values will only be read from the device, if the buffered values are older
* then 1 second (being exactly the maximum sampling time for DHT devices).
*
* This buffering does further introduce a coupling between both SAUL endpoints,
* meaning that if you read from both endpoints after each other, both values
* are from the same sensor reading.
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*
* @}
*/
#include <string.h>
#include "saul.h"
#include "dht.h"
static int read_temp(const void *dev, phydat_t *res)
{
if (dht_read((dht_t *)dev, &res->val[0], NULL)) {
return -ECANCELED;
}
res->unit = UNIT_TEMP_C;
res->scale = -1;
return 1;
}
static int read_hum(const void *dev, phydat_t *res)
{
if (dht_read((dht_t *)dev, NULL, &res->val[0])) {
return -ECANCELED;
}
res->unit = UNIT_PERCENT;
res->scale = -1;
return 1;
}
const saul_driver_t dht_temp_saul_driver = {
.read = read_temp,
.write = saul_write_notsup,
.type = SAUL_SENSE_TEMP
};
const saul_driver_t dht_hum_saul_driver = {
.read = read_hum,
.write = saul_write_notsup,
.type = SAUL_SENSE_HUM
};