drivers/sensors: add support of InvenSense MPU-9250 sensor

include/nuttx/sensors/mpu9250.h

@@ -0,0 +1,170 @@
+/****************************************************************************
+ * include/nuttx/sensors/mpu9250.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_SENSORS_MPU9250_H
+#define __INCLUDE_NUTTX_SENSORS_MPU9250_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/sensors/sensor.h>
+#include <nuttx/sensors/ioctl.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Sets bit @n */
+
+#define BIT(n)  (1 << (n))
+
+/* Creates a mask of @m bits, i.e. MASK(2) -> 00000011 */
+
+#define MASK(m) (BIT(m) - 1)
+
+/* Masks and shifts @v into bit field @m */
+
+#define TO_BITFIELD(m,v) (((v) & MASK(m ##_WIDTH)) << (m ##_SHIFT))
+
+/* Un-masks and un-shifts bit field @m from @v */
+
+#define FROM_BITFIELD(m,v) (((v) >> (m ##_SHIFT)) & MASK(m ##_WIDTH))
+
+/* SPI read/write codes */
+
+#define MPU_REG_READ  0x80
+#define MPU_REG_WRITE 0
+#define CONSTANTS_ONE_G 9.8f
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* GYRO_CONFIG */
+
+enum gyro_config_bit
+{
+  /* GYRO_FS_SEL [4:3] */
+
+  GYRO_FS_SEL_250_DPS   = 0, /* 0b00000 */
+  GYRO_FS_SEL_500_DPS   = 1, /* 0b01000 */
+  GYRO_FS_SEL_1000_DPS  = 2, /* 0b10000 */
+  GYRO_FS_SEL_2000_DPS  = 3, /* 0b11000 */
+
+  /* FCHOICE_B [1:0] */
+
+  FCHOICE_B_BYPASS_DLPF  = BIT(1) | BIT(0),
+};
+
+/* ACCEL_CONFIG */
+
+enum accel_config_bit
+{
+  /* ACCEL_FS_SEL [4:3] */
+
+  ACCEL_FS_SEL_2G  = 0, /* 0b00000 */
+  ACCEL_FS_SEL_4G  = 1, /* 0b01000 */
+  ACCEL_FS_SEL_8G  = 2, /* 0b10000 */
+  ACCEL_FS_SEL_16G = 3, /* 0b11000 */
+};
+
+/* These structures are defined elsewhere, and we don't need their
+ * definitions here.
+ */
+
+#ifdef CONFIG_MPU9250_SPI
+struct spi_dev_s;
+#else
+struct i2c_master_s;
+#endif
+
+/* Specifies the initial chip configuration and location.
+ *
+ * The chip supports both SPI and I2C interfaces, but you wouldn't use
+ * both at the same time on the same chip. It isn't an error to have
+ * one chip of each flavor in the system, though, so it's not an
+ * either-or configuration item.
+ *
+ * Important note :
+ *
+ * The driver determines which interface type to use according to
+ * which of the two groups of fields is non-NULL.  Since support for
+ * I2C and SPI are individually configurable, however, users should
+ * let the compiler clear unused fields instead of setting unused
+ * fields to NULL directly. For example, if using SPI and a
+ * stack-allocated instance:
+ *
+ *    struct mpu_config_s mpuc;
+ *    memset(&mpuc, 0, sizeof(mpuc)); * sets i2c to NULL, if present *
+ *    mpuc.spi = ...;
+ *
+ * Or, if using dynamic memory allocation and I2C:
+ *
+ *    struct mpu_config_s* mpuc;
+ *    mpuc = kmm_malloc(sizeof(*mpuc));
+ *    memset(mpuc, 0, sizeof(*mpuc)); * sets spi to NULL, if present *
+ *    mpuc.i2c = ...;
+ *
+ * The above examples will avoid compile-time errors unless the user
+ * forgets to enable their preferred interface type, and will allow
+ * them to disable or enable the unused interface type without
+ * changing their code.
+ *
+ */
+
+struct mpu9250_config_s
+{
+#ifdef CONFIG_MPU9250_SPI
+  /* For users on SPI.
+   *
+   *  spi_devid : the SPI master's slave-select number
+   *              for the chip, as used in SPI_SELECT(..., dev_id, ...)
+   *  spi       : the SPI master device, as used in SPI_SELECT(spi, ..., ...)
+   */
+
+  FAR struct spi_dev_s *spi;
+  int spi_devid;
+#else
+  /* For users on I2C.
+   *
+   *  i2c  : the I2C master device
+   *  addr : the I2C address.
+   */
+
+  FAR struct i2c_master_s *i2c;
+  int addr;
+#endif
+  };
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/* Declares the existence of an mpu9250 chip, wired according to
+ * config; creates an interface to it at path.
+ *
+ * Returns 0 on success, or negative errno.
+ */
+
+int mpu9250_register(int devno, FAR struct mpu9250_config_s *config);
+
+#endif /* __INCLUDE_NUTTX_SENSORS_MPU9250_H */