drivers/dht: added SAUL support

drivers/dht/dht.c

@@ -9,7 +9,7 @@
  */
 
 /**
- * @ingroup     driver_dht
+ * @ingroup     drivers_dht
  * @{
  *
  * @file
@@ -71,6 +71,12 @@ void dht_auto_init(void)
         if (dht_init(&dht_devs[i], &dht_params[i]) < 0) {
             LOG_ERROR("Unable to initialize DHT sensor #%i\n", i);
         }
+#ifdef MODULE_SAUL_REG
+        for (int j = 0; j < 2; j++) {
+            dht_saul_reg[i][j].dev = &dht_devs[i];
+            saul_reg_add(&dht_saul_reg[i][j]);
+        }
+#endif
     }
 }
 

drivers/dht/dht_saul.c

@@ -0,0 +1,80 @@
+/*
+ * 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"
+#include "xtimer.h"
+
+#define DHT_SAUL_HOLD_TIME      (1000 * 1000U)  /* 1s */
+
+static int16_t temp, hum;
+static uint32_t last = 0;
+
+static int check_and_read(void *dev, phydat_t *res, int16_t *val, uint8_t unit)
+{
+    dht_t *d = (dht_t *)dev;
+    uint32_t now = xtimer_now();
+
+    if ((now - last) > DHT_SAUL_HOLD_TIME) {
+        dht_read(d, &temp, &hum);
+        last = now;
+    }
+    else {
+        (void)d;
+    }
+
+    res->val[0] = *val;
+    memset(&res->val[1], 0, 2 * sizeof(int16_t));
+    res->unit = unit;
+    res->scale = -1;
+    return 1;
+}
+
+static int read_temp(void *dev, phydat_t *res)
+{
+    return check_and_read(dev, res, &temp, UNIT_TEMP_C);
+}
+
+static int read_hum(void *dev, phydat_t *res)
+{
+    return check_and_read(dev, res, &hum, UNIT_PERCENT);
+}
+
+const saul_driver_t dht_temp_saul_driver = {
+    .read = read_temp,
+    .write = saul_notsup,
+    .type = SAUL_SENSE_TEMP
+};
+
+const saul_driver_t dht_hum_saul_driver = {
+    .read = read_hum,
+    .write = saul_notsup,
+    .type = SAUL_SENSE_HUM
+};

drivers/dht/include/dht_params.h

@@ -20,6 +20,8 @@
 #define DHT_PARAMS_H
 
 #include "board.h"
+#include "dht.h"
+#include "saul_reg.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -61,6 +63,25 @@ static const dht_params_t dht_params[] =
  */
 #define DHT_NUMOF       (sizeof(dht_params) / sizeof(dht_params[0]))
 
+#ifdef MODULE_SAUL_REG
+/**
+ * @brief   Allocate and configure entries to the SAUL registry
+ */
+saul_reg_t dht_saul_reg[][2] =
+{
+    {
+        {
+            .name = "dht-temp",
+            .driver = &dht_temp_saul_driver
+        },
+        {
+            .name = "dht-hum",
+            .driver = &dht_hum_saul_driver
+        }
+    }
+};
+#endif
+
 #ifdef __cplusplus
 }
 #endif

drivers/include/dht.h

@@ -30,6 +30,7 @@
 
 #include <stdint.h>
 
+#include "saul.h"
 #include "periph/gpio.h"
 
 #ifdef __cplusplus
@@ -68,6 +69,14 @@ typedef struct {
  */
 typedef dht_t dht_params_t;
 
+/**
+ * @brief export SAUL endpoints
+ * @{
+ */
+extern const saul_driver_t dht_temp_saul_driver;
+extern const saul_driver_t dht_hum_saul_driver;
+/** @} */
+
 /**
  * @brief auto-initialize all configured DHT devices
  */