Import of the watch repository from Pebble

src/fw/drivers/mag.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "util/attributes.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+
+//! @internal
+//! Structure containing 3-axis magnetometer data
+typedef struct PACKED {
+ //! magnetic field along the x axis
+ int16_t x;
+ //! magnetic field along the y axis
+ int16_t y;
+ //! magnetic field along the z axis
+ int16_t z;
+} MagData;
+
+typedef enum {
+  MagReadSuccess = 0,
+  MagReadClobbered = -1,
+  MagReadCommunicationFail = -2,
+  MagReadMagOff = -3,
+  MagReadNoMag = -4,
+} MagReadStatus;
+
+typedef enum {
+  MagSampleRate20Hz,
+  MagSampleRate5Hz
+} MagSampleRate;
+
+//! Enable the mag hardware and increment the refcount. Must be matched with a call to
+//! mag_release.
+void mag_use(void);
+
+//! Enable the mag hardware, configure it in sampling mode and increment the refcount. Must be
+//! matched with a call to mag_release.
+void mag_start_sampling(void);
+
+//! Release the mag hardware and decrement the refcount. This will turn off the hardware if no one
+//! else is still using it (the refcount is still non-zero).
+void mag_release(void);
+
+MagReadStatus mag_read_data(MagData *data);
+
+bool mag_change_sample_rate(MagSampleRate rate);
+