[swing] add mission baro board file

sw/airborne/boards/swing/baro_board.c

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2017 Gautier Hattenberger <gautier.hattenberger@enac.fr>
+ *
+ * This file is part of Paparazzi.
+ *
+ * Paparazzi is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * Paparazzi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with paparazzi; see the file COPYING.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file boards/swing/baro_board.c
+ * Paparazzi Swing Baro Sensor implementation.
+ * Sensor is LPS22HB (I2C) from ST but is accessed through sysfs interface
+ */
+
+#include "subsystems/sensors/baro.h"
+#include "subsystems/abi.h"
+#include "baro_board.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <linux/input.h>
+
+static bool baro_swing_available;
+static int32_t baro_swing_raw;
+static pthread_mutex_t baro_swing_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+/**
+ * Check baro thread
+ * TODO something better ?
+ */
+static void *baro_read(void *data __attribute__((unused)))
+{
+  struct input_event ev;
+  ssize_t n;
+
+  int fd_sonar = open("/dev/input/baro_event", O_RDONLY);
+  if (fd_sonar == -1) {
+    printf("Unable to open baro event to read pressure\n");
+    return NULL;
+  }
+
+  while (TRUE) {
+    /* Check new pressure */
+    n = read(fd_sonar, &ev, sizeof(ev));
+    if (n == sizeof(ev) && ev.type == EV_ABS && ev.code == ABS_PRESSURE) {
+      pthread_mutex_lock(&baro_swing_mutex);
+      baro_swing_available = true;
+      baro_swing_raw = ev.value;
+      pthread_mutex_unlock(&baro_swing_mutex);
+    }
+
+    // Wait 100ms
+    //usleep(100000);
+  }
+
+  return NULL;
+}
+
+void baro_init(void)
+{
+  baro_swing_available = false;
+  baro_swing_raw = 0;
+
+  /* Start baro reading thread */
+  pthread_t baro_thread;
+  if (pthread_create(&baro_thread, NULL, baro_read, NULL) != 0) {
+    printf("[swing_board] Could not create baro reading thread!\n");
+  }
+
+}
+
+void baro_periodic(void) {}
+
+
+void baro_event(void)
+{
+  pthread_mutex_lock(&baro_swing_mutex);
+  if (baro_swing_available) {
+    // From datasheet: raw_pressure / 4096 -> pressure in hPa
+    // send data in Pa
+    float pressure = 100.f * ((float)baro_swing_raw) / 4096.f;
+    AbiSendMsgBARO_ABS(BARO_BOARD_SENDER_ID, pressure);
+    baro_swing_available = false;
+  }
+  pthread_mutex_unlock(&baro_swing_mutex);
+}
+