added temperature reader

controller/drivers/adafruit/source/common_dht_read.c

@@ -0,0 +1,66 @@
+// Copyright (c) 2014 Adafruit Industries
+// Author: Tony DiCola
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+#include <errno.h>
+#include <sched.h>
+#include <string.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include "common_dht_read.h"
+
+void busy_wait_milliseconds(uint32_t millis) {
+  // Set delay time period.
+  struct timeval deltatime;
+  deltatime.tv_sec = millis / 1000;
+  deltatime.tv_usec = (millis % 1000) * 1000;
+  struct timeval walltime;
+  // Get current time and add delay to find end time.
+  gettimeofday(&walltime, NULL);
+  struct timeval endtime;
+  timeradd(&walltime, &deltatime, &endtime);
+  // Tight loop to waste time (and CPU) until enough time as elapsed.
+  while (timercmp(&walltime, &endtime, <)) {
+    gettimeofday(&walltime, NULL);
+  }
+}
+
+void sleep_milliseconds(uint32_t millis) {
+  struct timespec sleep;
+  sleep.tv_sec = millis / 1000;
+  sleep.tv_nsec = (millis % 1000) * 1000000L;
+  while (clock_nanosleep(CLOCK_MONOTONIC, 0, &sleep, &sleep) && errno == EINTR);
+}
+
+void set_max_priority(void) {
+  struct sched_param sched;
+  memset(&sched, 0, sizeof(sched));
+  // Use FIFO scheduler with highest priority for the lowest chance of the kernel context switching.
+  sched.sched_priority = sched_get_priority_max(SCHED_FIFO);
+  sched_setscheduler(0, SCHED_FIFO, &sched);
+}
+
+void set_default_priority(void) {
+  struct sched_param sched;
+  memset(&sched, 0, sizeof(sched));
+  // Go back to default scheduler with default 0 priority.
+  sched.sched_priority = 0;
+  sched_setscheduler(0, SCHED_OTHER, &sched);
+}