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nuttx/drivers/sensors/mpu60x0.c
Petro Karashchenko 09b3fb25ab drivers: remove unimplemented open/close/ioctl interfaces 
Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>
2022-04-15 16:56:25 +08:00

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/****************************************************************************
* drivers/sensors/mpu60x0.c
*
* 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.
*
****************************************************************************/
/****************************************************************************
* TODO: Theory of Operation
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <errno.h>
#include <debug.h>
#include <string.h>
#include <limits.h>
#include <nuttx/mutex.h>
#include <nuttx/signal.h>
#include <nuttx/compiler.h>
#include <nuttx/kmalloc.h>
#ifdef CONFIG_MPU60X0_SPI
#include <nuttx/spi/spi.h>
#else
#include <nuttx/i2c/i2c_master.h>
#endif
#include <nuttx/fs/fs.h>
#include <nuttx/sensors/mpu60x0.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) - 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
/****************************************************************************
* Private Types
****************************************************************************/
enum mpu_regaddr_e
{
SELF_TEST_X = 0x0d,
SELF_TEST_Y = 0x0e,
SELF_TEST_Z = 0x0f,
SELF_TEST_A = 0x10,
SMPLRT_DIV = 0x19,
/* __SHIFT : number of empty bits to the right of the field
* __WIDTH : width of the field, in bits
*
* single-bit fields don't have __SHIFT or __mask
*/
CONFIG = 0x1a,
CONFIG__EXT_SYNC_SET__SHIFT = 3,
CONFIG__EXT_SYNC_SET__WIDTH = 2,
CONFIG__DLPF_CFG__SHIFT = 0,
CONFIG__DLPF_CFG__WIDTH = 2,
GYRO_CONFIG = 0x1b,
GYRO_CONFIG__XG_ST = BIT(7),
GYRO_CONFIG__YG_ST = BIT(6),
GYRO_CONFIG__ZG_ST = BIT(5),
GYRO_CONFIG__FS_SEL__SHIFT = 3,
GYRO_CONFIG__FS_SEL__WIDTH = 2,
ACCEL_CONFIG = 0x1c,
ACCEL_CONFIG__XA_ST = BIT(7),
ACCEL_CONFIG__YA_ST = BIT(6),
ACCEL_CONFIG__ZA_ST = BIT(5),
ACCEL_CONFIG__AFS_SEL__SHIFT = 3,
ACCEL_CONFIG__AFS_SEL__WIDTH = 2,
MOT_THR = 0x1f,
FIFO_EN = 0x23,
I2C_MST_CTRL = 0x24,
I2C_SLV0_ADDR = 0x25,
I2C_SLV0_REG = 0x26,
I2C_SLV0_CTRL = 0x27,
I2C_SLV1_ADDR = 0x28,
I2C_SLV1_REG = 0x29,
I2C_SLV1_CTRL = 0x2a,
I2C_SLV2_ADDR = 0x2b,
I2C_SLV2_REG = 0x2c,
I2C_SLV2_CTRL = 0x2d,
I2C_SLV3_ADDR = 0x2e,
I2C_SLV3_REG = 0x2f,
I2C_SLV3_CTRL = 0x30,
I2C_SLV4_ADDR = 0x31,
I2C_SLV4_REG = 0x32,
I2C_SLV4_DO = 0x33,
I2C_SLV4_CTRL = 0x34,
I2C_SLV4_DI = 0x35, /* RO */
I2C_MST_STATUS = 0x36, /* RO */
INT_PIN_CFG = 0x37,
INT_PIN_CFG__INT_LEVEL = BIT(7),
INT_PIN_CFG__INT_OPEN = BIT(6),
INT_PIN_CFG__LATCH_INT_EN = BIT(5),
INT_PIN_CFG__INT_RD_CLEAR = BIT(4),
INT_PIN_CFG__FSYNC_INT_LEVEL = BIT(3),
INT_PIN_CFG__FSYNC_INT_EN = BIT(2),
INT_PIN_CFG__I2C_BYPASS_EN = BIT(1),
INT_ENABLE = 0x38,
INT_STATUS = 0x3a, /* RO */
ACCEL_XOUT_H = 0x3b, /* RO */
ACCEL_XOUT_L = 0x3c, /* RO */
ACCEL_YOUT_H = 0x3d, /* RO */
ACCEL_YOUT_L = 0x3e, /* RO */
ACCEL_ZOUT_H = 0x3f, /* RO */
ACCEL_ZOUT_L = 0x40, /* RO */
TEMP_OUT_H = 0x41, /* RO */
TEMP_OUT_L = 0x42, /* RO */
GYRO_XOUT_H = 0x43, /* RO */
GYRO_XOUT_L = 0x44, /* RO */
GYRO_YOUT_H = 0x45, /* RO */
GYRO_YOUT_L = 0x46, /* RO */
GYRO_ZOUT_H = 0x47, /* RO */
GYRO_ZOUT_L = 0x48, /* RO */
EXT_SENS_DATA_00 = 0x49, /* RO */
EXT_SENS_DATA_01 = 0x4a, /* RO */
EXT_SENS_DATA_02 = 0x4b, /* RO */
EXT_SENS_DATA_03 = 0x4c, /* RO */
EXT_SENS_DATA_04 = 0x4d, /* RO */
EXT_SENS_DATA_05 = 0x4e, /* RO */
EXT_SENS_DATA_06 = 0x4f, /* RO */
EXT_SENS_DATA_07 = 0x50, /* RO */
EXT_SENS_DATA_08 = 0x51, /* RO */
EXT_SENS_DATA_09 = 0x52, /* RO */
EXT_SENS_DATA_10 = 0x53, /* RO */
EXT_SENS_DATA_11 = 0x54, /* RO */
EXT_SENS_DATA_12 = 0x55, /* RO */
EXT_SENS_DATA_13 = 0x56, /* RO */
EXT_SENS_DATA_14 = 0x57, /* RO */
EXT_SENS_DATA_15 = 0x58, /* RO */
EXT_SENS_DATA_16 = 0x59, /* RO */
EXT_SENS_DATA_17 = 0x5a, /* RO */
EXT_SENS_DATA_18 = 0x5b, /* RO */
EXT_SENS_DATA_19 = 0x5c, /* RO */
EXT_SENS_DATA_20 = 0x5d, /* RO */
EXT_SENS_DATA_21 = 0x5e, /* RO */
EXT_SENS_DATA_22 = 0x5f, /* RO */
EXT_SENS_DATA_23 = 0x60, /* RO */
I2C_SLV0_DO = 0x63,
I2C_SLV1_DO = 0x64,
I2C_SLV2_DO = 0x65,
I2C_SLV3_DO = 0x66,
I2C_MST_DELAY_CTRL = 0x67,
SIGNAL_PATH_RESET = 0x68,
SIGNAL_PATH_RESET__GYRO_RESET = BIT(2),
SIGNAL_PATH_RESET__ACCEL_RESET = BIT(1),
SIGNAL_PATH_RESET__TEMP_RESET = BIT(0),
SIGNAL_PATH_RESET__ALL_RESET = BIT(3) - 1,
MOT_DETECT_CTRL = 0x69,
USER_CTRL = 0x6a,
USER_CTRL__FIFO_EN = BIT(6),
USER_CTRL__I2C_MST_EN = BIT(5),
USER_CTRL__I2C_IF_DIS = BIT(4),
USER_CTRL__FIFO_RESET = BIT(2),
USER_CTRL__I2C_MST_RESET = BIT(1),
USER_CTRL__SIG_COND_RESET = BIT(0),
PWR_MGMT_1 = 0x6b, /* Reset: 0x40 */
PWR_MGMT_1__DEVICE_RESET = BIT(7),
PWR_MGMT_1__SLEEP = BIT(6),
PWR_MGMT_1__CYCLE = BIT(5),
PWR_MGMT_1__TEMP_DIS = BIT(3),
PWR_MGMT_1__CLK_SEL__SHIFT = 0,
PWR_MGMT_1__CLK_SEL__WIDTH = 3,
PWR_MGMT_2 = 0x6c,
FIFO_COUNTH = 0x72,
FIFO_COUNTL = 0x73,
FIFO_R_W = 0x74,
WHO_AM_I = 0x75, /* RO reset: 0x68 */
};
/* Describes the mpu60x0 sensor register file. This structure reflects
* the underlying hardware, so don't change it!
*/
begin_packed_struct struct sensor_data_s
{
int16_t x_accel;
int16_t y_accel;
int16_t z_accel;
int16_t temp;
int16_t x_gyro;
int16_t y_gyro;
int16_t z_gyro;
} end_packed_struct;
/* Used by the driver to manage the device */
struct mpu_dev_s
{
mutex_t lock; /* mutex for this structure */
struct mpu_config_s config; /* board-specific information */
struct sensor_data_s buf; /* temporary buffer (for read(), etc.) */
size_t bufpos; /* cursor into @buf, in bytes (!) */
};
/****************************************************************************
* Private Function Function Prototypes
****************************************************************************/
static int mpu_open(FAR struct file *filep);
static int mpu_close(FAR struct file *filep);
static ssize_t mpu_read(FAR struct file *filep, FAR char *buf, size_t len);
static ssize_t mpu_write(FAR struct file *filep, FAR const char *buf,
size_t len);
static off_t mpu_seek(FAR struct file *filep, off_t offset, int whence);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_mpu_fops =
{
mpu_open, /* open */
mpu_close, /* close */
mpu_read, /* read */
mpu_write, /* write */
mpu_seek, /* seek */
NULL, /* ioctl */
NULL /* poll */
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
, NULL /* unlink */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/* NOTE :
*
* In all of the following code, functions named with a double leading
* underscore '__' must be invoked ONLY if the mpu_dev_s lock is
* already held. Failure to do this might cause the transaction to get
* interrupted, which will likely confuse the data you get back.
*
* The mpu_dev_s lock is NOT the same thing as, i.e. the SPI master
* interface lock: the latter protects the bus interface hardware
* (which may have other SPI devices attached), the former protects
* the chip and its associated data.
*/
#ifdef CONFIG_MPU60X0_SPI
/* __mpu_read_reg(), but for spi-connected devices. See that function
* for documentation.
*/
static int __mpu_read_reg_spi(FAR struct mpu_dev_s *dev,
enum mpu_regaddr_e reg_addr,
FAR uint8_t *buf, uint8_t len)
{
int ret;
FAR struct spi_dev_s *spi = dev->config.spi;
int id = dev->config.spi_devid;
/* We'll probably return the number of bytes asked for. */
ret = len;
/* Grab and configure the SPI master device: always mode 0, 20MHz if it's a
* data register, 1MHz otherwise (per datasheet).
*/
SPI_LOCK(spi, true);
SPI_SETMODE(spi, SPIDEV_MODE0);
if ((reg_addr >= ACCEL_XOUT_H) && ((reg_addr + len) <= I2C_SLV0_DO))
{
SPI_SETFREQUENCY(spi, 20000000);
}
else
{
SPI_SETFREQUENCY(spi, 1000000);
}
/* Select the chip. */
SPI_SELECT(spi, id, true);
/* Send the read request. */
SPI_SEND(spi, reg_addr | MPU_REG_READ);
/* Clock in the data. */
while (0 != len--)
{
*buf++ = (uint8_t) (SPI_SEND(spi, 0xff));
}
/* Deselect the chip, release the SPI master. */
SPI_SELECT(spi, id, false);
SPI_LOCK(spi, false);
return ret;
}
/* __mpu_write_reg(), but for SPI connections. */
static int __mpu_write_reg_spi(FAR struct mpu_dev_s *dev,
enum mpu_regaddr_e reg_addr,
FAR const uint8_t * buf, uint8_t len)
{
int ret;
FAR struct spi_dev_s *spi = dev->config.spi;
int id = dev->config.spi_devid;
/* Hopefully, we'll return all the bytes they're asking for. */
ret = len;
/* Grab and configure the SPI master device. */
SPI_LOCK(spi, true);
SPI_SETMODE(spi, SPIDEV_MODE0);
SPI_SETFREQUENCY(spi, 1000000);
/* Select the chip. */
SPI_SELECT(spi, id, true);
/* Send the write request. */
SPI_SEND(spi, reg_addr | MPU_REG_WRITE);
/* Send the data. */
while (0 != len--)
{
SPI_SEND(spi, *buf++);
}
/* Release the chip and SPI master. */
SPI_SELECT(spi, id, false);
SPI_LOCK(spi, false);
return ret;
}
#else
/* __mpu_read_reg(), but for i2c-connected devices. */
static int __mpu_read_reg_i2c(FAR struct mpu_dev_s *dev,
enum mpu_regaddr_e reg_addr,
FAR uint8_t *buf, uint8_t len)
{
int ret;
struct i2c_msg_s msg[2];
msg[0].frequency = CONFIG_MPU60X0_I2C_FREQ;
msg[0].addr = dev->config.addr;
msg[0].flags = I2C_M_NOSTOP;
msg[0].buffer = &reg_addr;
msg[0].length = 1;
msg[1].frequency = CONFIG_MPU60X0_I2C_FREQ;
msg[1].addr = dev->config.addr;
msg[1].flags = I2C_M_READ;
msg[1].buffer = buf;
msg[1].length = len;
ret = I2C_TRANSFER(dev->config.i2c, msg, 2);
if (ret < 0)
{
snerr("ERROR: I2C_TRANSFER(read) failed: %d\n", ret);
return ret;
}
return OK;
}
static int __mpu_write_reg_i2c(FAR struct mpu_dev_s *dev,
enum mpu_regaddr_e reg_addr,
FAR const uint8_t *buf, uint8_t len)
{
int ret;
struct i2c_msg_s msg[2];
msg[0].frequency = CONFIG_MPU60X0_I2C_FREQ;
msg[0].addr = dev->config.addr;
msg[0].flags = I2C_M_NOSTOP;
msg[0].buffer = &reg_addr;
msg[0].length = 1;
msg[1].frequency = CONFIG_MPU60X0_I2C_FREQ;
msg[1].addr = dev->config.addr;
msg[1].flags = I2C_M_NOSTART;
msg[1].buffer = (FAR uint8_t *)buf;
msg[1].length = len;
ret = I2C_TRANSFER(dev->config.i2c, msg, 2);
if (ret < 0)
{
snerr("ERROR: I2C_TRANSFER(write) failed: %d\n", ret);
return ret;
}
return OK;
}
#endif /* CONFIG_MPU60X0_SPI */
/* __mpu_read_reg()
*
* Reads a block of @len byte-wide registers, starting at @reg_addr,
* from the device connected to @dev. Bytes are returned in @buf,
* which must have a capacity of at least @len bytes.
*
* Note: The caller must hold @dev->lock before calling this function.
*
* Returns number of bytes read, or a negative errno.
*/
static inline int __mpu_read_reg(FAR struct mpu_dev_s *dev,
enum mpu_regaddr_e reg_addr,
FAR uint8_t *buf, uint8_t len)
{
#ifdef CONFIG_MPU60X0_SPI
/* If we're wired to SPI, use that function. */
if (dev->config.spi != NULL)
{
return __mpu_read_reg_spi(dev, reg_addr, buf, len);
}
#else
/* If we're wired to I2C, use that function. */
if (dev->config.i2c != NULL)
{
return __mpu_read_reg_i2c(dev, reg_addr, buf, len);
}
#endif
/* If we get this far, it's because we can't "find" our device. */
return -ENODEV;
}
/* __mpu_write_reg()
*
* Writes a block of @len byte-wide registers, starting at @reg_addr,
* using the values in @buf to the device connected to @dev. Register
* values are taken in numerical order from @buf, i.e.:
*
* buf[0] -> register[@reg_addr]
* buf[1] -> register[@reg_addr + 1]
* ...
*
* Note: The caller must hold @dev->lock before calling this function.
*
* Returns number of bytes written, or a negative errno.
*/
static inline int __mpu_write_reg(FAR struct mpu_dev_s *dev,
enum mpu_regaddr_e reg_addr,
FAR const uint8_t *buf, uint8_t len)
{
#ifdef CONFIG_MPU60X0_SPI
/* If we're connected to SPI, use that function. */
if (dev->config.spi != NULL)
{
return __mpu_write_reg_spi(dev, reg_addr, buf, len);
}
#else
if (dev->config.i2c != NULL)
{
return __mpu_write_reg_i2c(dev, reg_addr, buf, len);
}
#endif
/* If we get this far, it's because we can't "find" our device. */
return -ENODEV;
}
/* __mpu_read_imu()
*
* Reads the whole IMU data file from @dev in one uninterrupted pass,
* placing the sampled values into @buf. This function is the only way
* to guarantee that the measured values are sampled as closely-spaced
* in time as the hardware permits, which is almost always what you
* want.
*/
static inline int __mpu_read_imu(FAR struct mpu_dev_s *dev,
FAR struct sensor_data_s *buf)
{
return __mpu_read_reg(dev, ACCEL_XOUT_H, (uint8_t *) buf, sizeof(*buf));
}
/* __mpu_read_pwr_mgmt_1()
*
* Returns the value of the PWR_MGMT_1 register from @dev.
*/
static inline uint8_t __mpu_read_pwr_mgmt_1(FAR struct mpu_dev_s *dev)
{
uint8_t buf = 0xff;
__mpu_read_reg(dev, PWR_MGMT_1, &buf, sizeof(buf));
return buf;
}
static inline int __mpu_write_signal_path_reset(FAR struct mpu_dev_s *dev,
uint8_t val)
{
return __mpu_write_reg(dev, SIGNAL_PATH_RESET, &val, sizeof(val));
}
static inline int __mpu_write_int_pin_cfg(FAR struct mpu_dev_s *dev,
uint8_t val)
{
return __mpu_write_reg(dev, INT_PIN_CFG, &val, sizeof(val));
}
static inline int __mpu_write_pwr_mgmt_1(FAR struct mpu_dev_s *dev,
uint8_t val)
{
return __mpu_write_reg(dev, PWR_MGMT_1, &val, sizeof(val));
}
static inline int __mpu_write_pwr_mgmt_2(FAR struct mpu_dev_s *dev,
uint8_t val)
{
return __mpu_write_reg(dev, PWR_MGMT_2, &val, sizeof(val));
}
static inline int __mpu_write_user_ctrl(FAR struct mpu_dev_s *dev,
uint8_t val)
{
return __mpu_write_reg(dev, USER_CTRL, &val, sizeof(val));
}
/* __mpu_write_gyro_config() :
*
* Sets the @fs_sel bit in GYRO_CONFIG to the value provided. Per the
* datasheet, the meaning of @fs_sel is as follows:
*
* GYRO_CONFIG(0x1b) : XG_ST YG_ST ZG_ST FS_SEL1 FS_SEL0 x x x
*
* XG_ST, YG_ST, ZG_ST : self-test (unsupported in this driver)
* 1 -> activate self-test on X, Y, and/or Z gyros
*
* FS_SEL[10] : full-scale range select
* 0 -> ± 250 deg/sec
* 1 -> ± 500 deg/sec
* 2 -> ± 1000 deg/sec
* 3 -> ± 2000 deg/sec
*/
static inline int __mpu_write_gyro_config(FAR struct mpu_dev_s *dev,
uint8_t fs_sel)
{
uint8_t val = TO_BITFIELD(GYRO_CONFIG__FS_SEL, fs_sel);
return __mpu_write_reg(dev, GYRO_CONFIG, &val, sizeof(val));
}
/* __mpu_write_accel_config() :
*
* Sets the @afs_sel bit in ACCEL_CONFIG to the value provided. Per
* the datasheet, the meaning of @afs_sel is as follows:
*
* ACCEL_CONFIG(0x1c) : XA_ST YA_ST ZA_ST AFS_SEL1 AFS_SEL0 x x x
*
* XA_ST, YA_ST, ZA_ST : self-test (unsupported in this driver)
* 1 -> activate self-test on X, Y, and/or Z accelerometers
*
* AFS_SEL[10] : full-scale range select
* 0 -> ± 2 g
* 1 -> ± 4 g
* 2 -> ± 8 g
* 3 -> ± 16 g
*/
static inline int __mpu_write_accel_config(FAR struct mpu_dev_s *dev,
uint8_t afs_sel)
{
uint8_t val = TO_BITFIELD(ACCEL_CONFIG__AFS_SEL, afs_sel);
return __mpu_write_reg(dev, ACCEL_CONFIG, &val, sizeof(val));
}
/* CONFIG (0x1a) : x x EXT_SYNC_SET[2..0] DLPF_CFG[2..0]
*
* EXT_SYNC_SET : frame sync bit position
* DLPF_CFG : digital low-pass filter bandwidth
* (see datasheet, it's ... complicated)
*/
static inline int __mpu_write_config(FAR struct mpu_dev_s *dev,
uint8_t ext_sync_set, uint8_t dlpf_cfg)
{
uint8_t val = TO_BITFIELD(CONFIG__EXT_SYNC_SET, ext_sync_set) |
TO_BITFIELD(CONFIG__DLPF_CFG, dlpf_cfg);
return __mpu_write_reg(dev, CONFIG, &val, sizeof(val));
}
/* WHO_AM_I (0x75) : read-only, always returns 0x68 for mpu60x0 */
static inline uint8_t __mpu_read_who_am_i(FAR struct mpu_dev_s *dev)
{
uint8_t val = 0xff;
__mpu_read_reg(dev, WHO_AM_I, &val, sizeof(val));
return val;
}
/* Locks and unlocks the @dev data structure (mutex).
*
* Use these functions any time you call one of the lock-dependent
* helper functions defined above.
*/
static void inline mpu_lock(FAR struct mpu_dev_s *dev)
{
nxmutex_lock(&dev->lock);
}
static void inline mpu_unlock(FAR struct mpu_dev_s *dev)
{
nxmutex_unlock(&dev->lock);
}
/* Resets the mpu60x0, sets it to a default configuration. */
static int mpu_reset(FAR struct mpu_dev_s *dev)
{
int ret;
#ifdef CONFIG_MPU60X0_SPI
if (dev->config.spi == NULL)
{
return -EINVAL;
}
#else
if (dev->config.i2c == NULL)
{
return -EINVAL;
}
#endif
mpu_lock(dev);
/* Awaken chip, issue hardware reset */
ret = __mpu_write_pwr_mgmt_1(dev, PWR_MGMT_1__DEVICE_RESET);
if (ret != OK)
{
snerr("Could not find mpu60x0!\n");
return ret;
}
/* Wait for reset cycle to finish (note: per the datasheet, we don't need
* to hold NSS for this)
*/
do
{
nxsig_usleep(50000); /* usecs (arbitrary) */
}
while (__mpu_read_pwr_mgmt_1(dev) & PWR_MGMT_1__DEVICE_RESET);
/* Reset signal paths */
__mpu_write_signal_path_reset(dev, SIGNAL_PATH_RESET__ALL_RESET);
nxsig_usleep(2000);
/* Disable SLEEP, use PLL with z-axis clock source */
__mpu_write_pwr_mgmt_1(dev, 3);
nxsig_usleep(2000);
/* Disable i2c if we're on spi. */
#ifdef CONFIG_MPU60X0_SPI
if (dev->config.spi)
{
__mpu_write_user_ctrl(dev, USER_CTRL__I2C_IF_DIS);
}
#endif
/* Disable low-power mode, enable all gyros and accelerometers */
__mpu_write_pwr_mgmt_2(dev, 0);
/* No FSYNC, set accel LPF at 184 Hz, gyro LPF at 188 Hz */
__mpu_write_config(dev, 0, 1);
/* ± 1000 deg/sec */
__mpu_write_gyro_config(dev, 2);
/* ± 8g */
__mpu_write_accel_config(dev, 2);
/* clear INT on any read (we aren't using that pin right now) */
__mpu_write_int_pin_cfg(dev, INT_PIN_CFG__INT_RD_CLEAR);
mpu_unlock(dev);
return 0;
}
/****************************************************************************
* Name: mpu_open
*
* Note: we don't deal with multiple users trying to access this interface at
* the same time. Until further notice, don't do that.
*
* And no, it's not as simple as just prohibiting concurrent opens or
* reads with a mutex: there are legit reasons for truy concurrent
* access, but they must be treated carefully in this interface lest a
* partial reader end up with a mixture of old and new samples. This
* will make some users unhappy.
*
****************************************************************************/
static int mpu_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mpu_dev_s *dev = inode->i_private;
/* Reset the register cache */
mpu_lock(dev);
dev->bufpos = 0;
mpu_unlock(dev);
return 0;
}
/****************************************************************************
* Name: mpu_close
****************************************************************************/
static int mpu_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mpu_dev_s *dev = inode->i_private;
/* Reset (clear) the register cache. */
mpu_lock(dev);
dev->bufpos = 0;
mpu_unlock(dev);
return 0;
}
/****************************************************************************
* Name: mpu_read
*
* Returns a snapshot of the accelerometer, temperature, and gyro registers.
*
* Note: the chip uses traditional, twos-complement notation, i.e. "0"
* is encoded as 0, and full-scale-negative is 0x8000, and
* full-scale-positive is 0x7fff. If we read the registers
* sequentially and directly into memory (as we do), the measurements
* from each sensor are captured as big endian words.
*
* In contrast, ASN.1 maps "0" to 0x8000, full-scale-negative to 0,
* and full-scale-positive to 0xffff. So if we want to send in a
* format that an ASN.1 PER-decoder would recognize, must:
*
* 1. Treat the register data/measurements as unsigned,
* 2. Add 0x8000 to each measurement, and then,
* 3. Send each word in big-endian order.
*
* The result of the above will be something you could neatly describe
* like this (confirmed with asn1scc):
*
* Sint16 ::= INTEGER(-32768..32767)
*
* Mpu60x0Sample ::= SEQUENCE
* {
* accel-X Sint16,
* accel-Y Sint16,
* accel-Z Sint16,
* temp Sint16,
* gyro-X Sint16,
* gyro-Y Sint16,
* gyro-Z Sint16
* }
*
****************************************************************************/
static ssize_t mpu_read(FAR struct file *filep, FAR char *buf, size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mpu_dev_s *dev = inode->i_private;
size_t send_len = 0;
mpu_lock(dev);
/* Populate the register cache if it seems empty. */
if (!dev->bufpos)
{
__mpu_read_imu(dev, &dev->buf);
}
/* Send the lesser of: available bytes, or amount requested. */
send_len = sizeof(dev->buf) - dev->bufpos;
if (send_len > len)
{
send_len = len;
}
if (send_len)
{
memcpy(buf, ((uint8_t *)&dev->buf) + dev->bufpos, send_len);
}
/* Move the cursor, to mark them as sent. */
dev->bufpos += send_len;
/* If we've sent the last byte, reset the buffer. */
if (dev->bufpos >= sizeof(dev->buf))
{
dev->bufpos = 0;
}
mpu_unlock(dev);
return send_len;
}
/****************************************************************************
* Name: mpu_write
****************************************************************************/
static ssize_t mpu_write(FAR struct file *filep, FAR const char *buf,
size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mpu_dev_s *dev = inode->i_private;
UNUSED(inode);
UNUSED(dev);
snerr("ERROR: %p %p %d\n", inode, dev, len);
return len;
}
/****************************************************************************
* Name: mpu60x0_seek
****************************************************************************/
static off_t mpu_seek(FAR struct file *filep, off_t offset, int whence)
{
FAR struct inode *inode = filep->f_inode;
FAR struct mpu_dev_s *dev = inode->i_private;
UNUSED(inode);
UNUSED(dev);
snerr("ERROR: %p %p\n", inode, dev);
return 0;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: mpu60x0_register
*
* Description:
* Registers the mpu60x0 interface as 'devpath'
*
* Input Parameters:
* devpath - The full path to the interface to register. E.g., "/dev/imu0"
* spi - SPI interface for chip communications
* config - Configuration information
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
int mpu60x0_register(FAR const char *path, FAR struct mpu_config_s *config)
{
FAR struct mpu_dev_s *priv;
int ret;
/* Without config info, we can't do anything. */
if (config == NULL)
{
return -EINVAL;
}
/* Initialize the device structure. */
priv = (FAR struct mpu_dev_s *)kmm_malloc(sizeof(struct mpu_dev_s));
if (priv == NULL)
{
snerr("ERROR: Failed to allocate mpu60x0 device instance\n");
return -ENOMEM;
}
memset(priv, 0, sizeof(*priv));
nxmutex_init(&priv->lock);
/* Keep a copy of the config structure, in case the caller discards
* theirs.
*/
priv->config = *config;
/* Reset the chip, to give it an initial configuration. */
ret = mpu_reset(priv);
if (ret < 0)
{
snerr("ERROR: Failed to configure mpu60x0: %d\n", ret);
nxmutex_destroy(&priv->lock);
kmm_free(priv);
return ret;
}
/* Register the device node. */
ret = register_driver(path, &g_mpu_fops, 0666, priv);
if (ret < 0)
{
snerr("ERROR: Failed to register mpu60x0 interface: %d\n", ret);
nxmutex_destroy(&priv->lock);
kmm_free(priv);
return ret;
}
return OK;
}
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