/*
	Copyright 2019 Benjamin Vedder	benjamin@vedder.se

	This file is part of the VESC firmware.

	The VESC firmware 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 3 of the License, or
    (at your option) any later version.

    The VESC firmware 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 this program.  If not, see <http://www.gnu.org/licenses/>.
    */

#include "imu.h"
#include "hw.h"
#include "mpu9150.h"
#include "ahrs.h"
#include "timer.h"
#include "terminal.h"
#include "commands.h"
#include "icm20948.h"
#include "bmi160_wrapper.h"
#include "lsm6ds3.h"
#include "utils.h"

#include <math.h>
#include <string.h>

// Private variables
static ATTITUDE_INFO m_att;
static float m_accel[3], m_gyro[3], m_mag[3];
static stkalign_t m_thd_work_area[THD_WORKING_AREA_SIZE(2048) / sizeof(stkalign_t)];
static i2c_bb_state m_i2c_bb;
static spi_bb_state m_spi_bb;
static ICM20948_STATE m_icm20948_state;
static BMI_STATE m_bmi_state;
static imu_config m_settings;
static float m_gyro_offset[3] = {0.0};
static systime_t init_time;
static bool imu_ready;

// Private functions
static void imu_read_callback(float *accel, float *gyro, float *mag);
static void terminal_gyro_info(int argc, const char **argv);
static void rotate(float *input, float *rotation, float *output);
int8_t user_i2c_read(uint8_t dev_addr, uint8_t reg_addr, uint8_t *data, uint16_t len);
int8_t user_i2c_write(uint8_t dev_addr, uint8_t reg_addr, uint8_t *data, uint16_t len);
int8_t user_spi_read(uint8_t dev_id, uint8_t reg_addr, uint8_t *data, uint16_t len);
int8_t user_spi_write(uint8_t dev_id, uint8_t reg_addr, uint8_t *data, uint16_t len);

void imu_init(imu_config *set) {
	m_settings = *set;
	memset(m_gyro_offset, 0, sizeof(m_gyro_offset));

	imu_stop();

	imu_ready = false;
	init_time = chVTGetSystemTimeX();
	ahrs_update_all_parameters(1.0, 10.0, 0.0, 2.0);

	ahrs_init_attitude_info(&m_att);

	mpu9150_set_rate_hz(set->sample_rate_hz);
	m_icm20948_state.rate_hz = set->sample_rate_hz;
	m_bmi_state.rate_hz = set->sample_rate_hz;
	lsm6ds3_set_rate_hz(set->sample_rate_hz);

	if (set->type == IMU_TYPE_INTERNAL) {
#ifdef MPU9X50_SDA_GPIO
		imu_init_mpu9x50(MPU9X50_SDA_GPIO, MPU9X50_SDA_PIN,
				MPU9X50_SCL_GPIO, MPU9X50_SCL_PIN);
#endif

#ifdef ICM20948_SDA_GPIO
		imu_init_icm20948(ICM20948_SDA_GPIO, ICM20948_SDA_PIN,
				ICM20948_SCL_GPIO, ICM20948_SCL_PIN, ICM20948_AD0_VAL);
#endif

#ifdef BMI160_SDA_GPIO
		imu_init_bmi160_i2c(BMI160_SDA_GPIO, BMI160_SDA_PIN,
				BMI160_SCL_GPIO, BMI160_SCL_PIN);
#endif

#ifdef LSM6DS3_SDA_GPIO
		imu_init_lsm6ds3(LSM6DS3_SDA_GPIO, LSM6DS3_SDA_PIN,
				LSM6DS3_SCL_GPIO, LSM6DS3_SCL_PIN);
#endif

#ifdef BMI160_SPI_PORT_NSS
		imu_init_bmi160_spi(
				BMI160_SPI_PORT_NSS, BMI160_SPI_PIN_NSS,
				BMI160_SPI_PORT_SCK, BMI160_SPI_PIN_SCK,
				BMI160_SPI_PORT_MOSI, BMI160_SPI_PIN_MOSI,
				BMI160_SPI_PORT_MISO, BMI160_SPI_PIN_MISO);
#endif
	} else if (set->type == IMU_TYPE_EXTERNAL_MPU9X50) {
		imu_init_mpu9x50(HW_I2C_SDA_PORT, HW_I2C_SDA_PIN,
				HW_I2C_SCL_PORT, HW_I2C_SCL_PIN);
	} else if (set->type == IMU_TYPE_EXTERNAL_ICM20948) {
		imu_init_icm20948(HW_I2C_SDA_PORT, HW_I2C_SDA_PIN,
				HW_I2C_SCL_PORT, HW_I2C_SCL_PIN, 0);
	} else if (set->type == IMU_TYPE_EXTERNAL_BMI160) {
		imu_init_bmi160_i2c(HW_I2C_SDA_PORT, HW_I2C_SDA_PIN,
				HW_I2C_SCL_PORT, HW_I2C_SCL_PIN);
	} else if(set->type == IMU_TYPE_EXTERNAL_LSM6DS3) {
		imu_init_lsm6ds3(HW_I2C_SDA_PORT, HW_I2C_SDA_PIN,
				HW_I2C_SCL_PORT, HW_I2C_SCL_PIN);
	} else if (set->type == IMU_TYPE_EXTERNAL_BMI160) {
		imu_init_bmi160_i2c(HW_I2C_SDA_PORT, HW_I2C_SDA_PIN,
				HW_I2C_SCL_PORT, HW_I2C_SCL_PIN);
	}

	terminal_register_command_callback(
			"imu_gyro_info",
			"Print gyro offsets",
			0,
			terminal_gyro_info);
}

i2c_bb_state *imu_get_i2c(void) {
	return &m_i2c_bb;
}

void imu_init_mpu9x50(stm32_gpio_t *sda_gpio, int sda_pin,
		stm32_gpio_t *scl_gpio, int scl_pin) {
	imu_stop();

	mpu9150_init(sda_gpio, sda_pin,
			scl_gpio, scl_pin,
			m_thd_work_area, sizeof(m_thd_work_area));
	mpu9150_set_read_callback(imu_read_callback);
}

void imu_init_icm20948(stm32_gpio_t *sda_gpio, int sda_pin,
		stm32_gpio_t *scl_gpio, int scl_pin, int ad0_val) {
	imu_stop();

	m_i2c_bb.sda_gpio = sda_gpio;
	m_i2c_bb.sda_pin = sda_pin;
	m_i2c_bb.scl_gpio = scl_gpio;
	m_i2c_bb.scl_pin = scl_pin;
	i2c_bb_init(&m_i2c_bb);

	icm20948_init(&m_icm20948_state,
			&m_i2c_bb, ad0_val,
			m_thd_work_area, sizeof(m_thd_work_area));
	icm20948_set_read_callback(&m_icm20948_state, imu_read_callback);
}

void imu_init_bmi160_i2c(stm32_gpio_t *sda_gpio, int sda_pin,
		stm32_gpio_t *scl_gpio, int scl_pin) {
	imu_stop();

	m_i2c_bb.sda_gpio = sda_gpio;
	m_i2c_bb.sda_pin = sda_pin;
	m_i2c_bb.scl_gpio = scl_gpio;
	m_i2c_bb.scl_pin = scl_pin;
	i2c_bb_init(&m_i2c_bb);

	m_bmi_state.sensor.id = BMI160_I2C_ADDR;
	m_bmi_state.sensor.interface = BMI160_I2C_INTF;
	m_bmi_state.sensor.read = user_i2c_read;
	m_bmi_state.sensor.write = user_i2c_write;

	bmi160_wrapper_init(&m_bmi_state, m_thd_work_area, sizeof(m_thd_work_area));
	bmi160_wrapper_set_read_callback(&m_bmi_state, imu_read_callback);
}

void imu_init_bmi160_spi(stm32_gpio_t *nss_gpio, int nss_pin,
		stm32_gpio_t *sck_gpio, int sck_pin, stm32_gpio_t *mosi_gpio, int mosi_pin,
		stm32_gpio_t *miso_gpio, int miso_pin) {
	imu_stop();

	m_spi_bb.nss_gpio = nss_gpio;
	m_spi_bb.nss_pin = nss_pin;
	m_spi_bb.sck_gpio = sck_gpio;
	m_spi_bb.sck_pin = sck_pin;
	m_spi_bb.mosi_gpio = mosi_gpio;
	m_spi_bb.mosi_pin = mosi_pin;
	m_spi_bb.miso_gpio = miso_gpio;
	m_spi_bb.miso_pin = miso_pin;

	spi_bb_init(&m_spi_bb);

	m_bmi_state.sensor.id = 0;
	m_bmi_state.sensor.interface = BMI160_SPI_INTF;
	m_bmi_state.sensor.read = user_spi_read;
	m_bmi_state.sensor.write = user_spi_write;

	bmi160_wrapper_init(&m_bmi_state, m_thd_work_area, sizeof(m_thd_work_area));

	bmi160_wrapper_set_read_callback(&m_bmi_state, imu_read_callback);
}

void imu_init_lsm6ds3(stm32_gpio_t *sda_gpio, int sda_pin,
		stm32_gpio_t *scl_gpio, int scl_pin) {

	lsm6ds3_init(sda_gpio, sda_pin,
				scl_gpio, scl_pin,
				m_thd_work_area, sizeof(m_thd_work_area));
	lsm6ds3_set_read_callback(imu_read_callback);

}

void imu_stop(void) {
	mpu9150_stop();
	icm20948_stop(&m_icm20948_state);
	bmi160_wrapper_stop(&m_bmi_state);
	lsm6ds3_stop();
}

bool imu_startup_done(void) {
	return imu_ready;
}

float imu_get_roll(void) {
	return ahrs_get_roll(&m_att);
}

float imu_get_pitch(void) {
	return ahrs_get_pitch(&m_att);
}

float imu_get_yaw(void) {
	return ahrs_get_yaw(&m_att);
}

void imu_get_rpy(float *rpy) {
	ahrs_get_roll_pitch_yaw(rpy, &m_att);
}

void imu_get_accel(float *accel) {
	memcpy(accel, m_accel, sizeof(m_accel));
}

void imu_get_gyro(float *gyro) {
	memcpy(gyro, m_gyro, sizeof(m_gyro));
}

void imu_get_mag(float *mag) {
	memcpy(mag, m_mag, sizeof(m_mag));
}

void imu_get_accel_derotated(float *accel) {
	float rpy[3];
	imu_get_rpy(rpy);

	const float ax = m_accel[0];
	const float ay = m_accel[1];
	const float az = m_accel[2];

	const float sr = sinf(rpy[0]);
	const float cr = -cosf(rpy[0]);
	const float sp = sinf(rpy[1]);
	const float cp = -cosf(rpy[1]);
	const float sy = sinf(rpy[2]);
	const float cy = cosf(rpy[2]);

	float c_ax = ax * cp + ay * sp * sr + az * sp * cr;
	float c_ay = ay * cr - az * sr;
	float c_az = -ax * sp + ay * cp * sr + az * cp * cr;
	float c_ax2 = cy * c_ax + sy * c_ay;
	float c_ay2 = sy * c_ax - cy * c_ay;

	accel[0] = c_ax2;
	accel[1] = c_ay2;
	accel[2] = c_az;
}

void imu_get_quaternions(float *q) {
	q[0] = m_att.q0;
	q[1] = m_att.q1;
	q[2] = m_att.q2;
	q[3] = m_att.q3;
}

void imu_get_calibration(float yaw, float *imu_cal) {
	// Backup current settings
	float backup_sample_rate = m_settings.sample_rate_hz;
	AHRS_MODE backup_ahrs_mode = m_settings.mode;
	float backup_roll = m_settings.rot_roll;
	float backup_pitch = m_settings.rot_pitch;
	float backup_yaw = m_settings.rot_yaw;
	float backup_accel_offset_x = m_settings.accel_offsets[0];
	float backup_accel_offset_y = m_settings.accel_offsets[1];
	float backup_accel_offset_z = m_settings.accel_offsets[2];
	float backup_gyro_offset_x = m_settings.gyro_offsets[0];
	float backup_gyro_offset_y = m_settings.gyro_offsets[1];
	float backup_gyro_offset_z = m_settings.gyro_offsets[2];
	float backup_gyro_comp_x = m_settings.gyro_offset_comp_fact[0];
	float backup_gyro_comp_y = m_settings.gyro_offset_comp_fact[1];
	float backup_gyro_comp_z = m_settings.gyro_offset_comp_fact[2];

	// Override settings
	m_settings.sample_rate_hz = 1000;
	m_settings.mode = AHRS_MODE_MADGWICK;
	ahrs_update_all_parameters(1.0, 10.0, 0.0, 2.0);
	m_settings.rot_roll = 0;
	m_settings.rot_pitch = 0;
	m_settings.rot_yaw = 0;
	m_settings.accel_offsets[0] = 0;
	m_settings.accel_offsets[1] = 0;
	m_settings.accel_offsets[2] = 0;
	m_settings.gyro_offsets[0] = 0;
	m_settings.gyro_offsets[1] = 0;
	m_settings.gyro_offsets[2] = 0;
	m_settings.gyro_offset_comp_fact[0] = 0;
	m_settings.gyro_offset_comp_fact[1] = 0;
	m_settings.gyro_offset_comp_fact[2] = 0;

	// Clear computed offsets
	m_gyro_offset[0] = 0;
	m_gyro_offset[1] = 0;
	m_gyro_offset[2] = 0;

	// Sample gyro for offsets
	float original_gyro_offsets[3] = {0, 0, 0};
	for (int i = 0; i < 1000; i++) {
		original_gyro_offsets[0] += m_gyro[0];
		original_gyro_offsets[1] += m_gyro[1];
		original_gyro_offsets[2] += m_gyro[2];
		chThdSleepMilliseconds(1);
	}
	original_gyro_offsets[0] /= 1000;
	original_gyro_offsets[1] /= 1000;
	original_gyro_offsets[2] /= 1000;

	// Set gyro offsets
	m_settings.gyro_offsets[0] = original_gyro_offsets[0];
	m_settings.gyro_offsets[1] = original_gyro_offsets[1];
	m_settings.gyro_offsets[2] = original_gyro_offsets[2];

	// Reset AHRS and wait 1.5 seconds (for AHRS to settle now that gyro is calibrated)
	ahrs_init_attitude_info(&m_att);
	chThdSleepMilliseconds(1500);

	// Sample roll
	float roll_sample = 0;
	for (int i = 0; i < 250; i++) {
		roll_sample += imu_get_roll();
		chThdSleepMilliseconds(1);
	}
	roll_sample = roll_sample / 250;

	// Set roll rotations to level out roll axis
	m_settings.rot_roll = -roll_sample * (180 / M_PI);

	// Rotate gyro offsets to match new IMU orientation
	float rotation1[3] = {m_settings.rot_roll, m_settings.rot_pitch, m_settings.rot_yaw};
	rotate(original_gyro_offsets, rotation1, m_settings.gyro_offsets);

	// Reset AHRS and wait 1.5 seconds (for AHRS to settle now that pitch is calibrated)
	ahrs_init_attitude_info(&m_att);
	chThdSleepMilliseconds(1500);

	// Sample pitch
	float pitch_sample = 0;
	for (int i = 0; i < 250; i++) {
		pitch_sample += imu_get_pitch();
		chThdSleepMilliseconds(1);
	}
	pitch_sample = pitch_sample / 250;

	// Set pitch rotation to level out pitch axis
	m_settings.rot_pitch = pitch_sample * (180 / M_PI);

	// Rotate imu offsets to match
	float rotation2[3] = {m_settings.rot_roll, m_settings.rot_pitch, m_settings.rot_yaw};
	rotate(original_gyro_offsets, rotation2, m_settings.gyro_offsets);

	// Set yaw rotations to match user input
	m_settings.rot_yaw = yaw;

	// Rotate gyro offsets to match new IMU orientation
	float rotation3[3] = {m_settings.rot_roll, m_settings.rot_pitch, m_settings.rot_yaw};
	rotate(original_gyro_offsets, rotation3, m_settings.gyro_offsets);

	// Note to future person interested in calibration:
	// This is where accel calibration should go, because at this point the values should be 0,0,1
	// All the IMU units I've tested haven't needed significant accel correction, so I've skipped it.
	// I'm worried that blindly setting them to 0,0,1 may do more harm that good (need more testing).

	// Return calibration
	imu_cal[0] = m_settings.rot_roll;
	imu_cal[1] = m_settings.rot_pitch;
	imu_cal[2] = m_settings.rot_yaw;
	imu_cal[3] = m_settings.accel_offsets[0];
	imu_cal[4] = m_settings.accel_offsets[1];
	imu_cal[5] = m_settings.accel_offsets[2];
	imu_cal[6] = m_settings.gyro_offsets[0];
	imu_cal[7] = m_settings.gyro_offsets[1];
	imu_cal[8] = m_settings.gyro_offsets[2];

	// Restore settings
	m_settings.sample_rate_hz = backup_sample_rate;
	m_settings.mode = backup_ahrs_mode;
	ahrs_update_all_parameters(
					m_settings.accel_confidence_decay,
					m_settings.mahony_kp,
					m_settings.mahony_ki,
					m_settings.madgwick_beta);
	m_settings.rot_roll = backup_roll;
	m_settings.rot_pitch = backup_pitch;
	m_settings.rot_yaw = backup_yaw;
	m_settings.accel_offsets[0] = backup_accel_offset_x;
	m_settings.accel_offsets[1] = backup_accel_offset_y;
	m_settings.accel_offsets[2] = backup_accel_offset_z;
	m_settings.gyro_offsets[0] = backup_gyro_offset_x;
	m_settings.gyro_offsets[1] = backup_gyro_offset_y;
	m_settings.gyro_offsets[2] = backup_gyro_offset_z;
	m_settings.gyro_offset_comp_fact[0] = backup_gyro_comp_x;
	m_settings.gyro_offset_comp_fact[1] = backup_gyro_comp_y;
	m_settings.gyro_offset_comp_fact[2] = backup_gyro_comp_z;
	ahrs_init_attitude_info(&m_att);
}

static void imu_read_callback(float *accel, float *gyro, float *mag) {
	static uint32_t last_time = 0;
	float dt = timer_seconds_elapsed_since(last_time);
	last_time = timer_time_now();

	if (!imu_ready && ST2MS(chVTGetSystemTimeX() - init_time) > 1000) {
		ahrs_update_all_parameters(
				m_settings.accel_confidence_decay,
				m_settings.mahony_kp,
				m_settings.mahony_ki,
				m_settings.madgwick_beta);
		imu_ready = true;
	}

#ifdef IMU_FLIP
	accel[0] *= -1.0;
	accel[2] *= -1.0;
	gyro[0] *= -1.0;
	gyro[2] *= -1.0;
	mag[0] *= -1.0;
	mag[2] *= -1.0;
#endif

#ifdef IMU_ROT_180
	accel[0] *= -1.0;
	accel[1] *= -1.0;
	gyro[0] *= -1.0;
	gyro[1] *= -1.0;
	mag[0] *= -1.0;
	mag[1] *= -1.0;
#endif

	// Rotate axes (ZYX)

	float s1 = sinf(m_settings.rot_yaw * M_PI / 180.0);
	float c1 = cosf(m_settings.rot_yaw * M_PI / 180.0);
	float s2 = sinf(m_settings.rot_pitch * M_PI / 180.0);
	float c2 = cosf(m_settings.rot_pitch * M_PI / 180.0);
	float s3 = sinf(m_settings.rot_roll * M_PI / 180.0);
	float c3 = cosf(m_settings.rot_roll * M_PI / 180.0);

	float m11 = c1 * c2;	float m12 = c1 * s2 * s3 - c3 * s1;	float m13 = s1 * s3 + c1 * c3 * s2;
	float m21 = c2 * s1;	float m22 = c1 * c3 + s1 * s2 * s3;	float m23 = c3 * s1 * s2 - c1 * s3;
	float m31 = -s2; 		float m32 = c2 * s3;				float m33 = c2 * c3;

	m_accel[0] = accel[0] * m11 + accel[1] * m12 + accel[2] * m13;
	m_accel[1] = accel[0] * m21 + accel[1] * m22 + accel[2] * m23;
	m_accel[2] = accel[0] * m31 + accel[1] * m32 + accel[2] * m33;

	m_gyro[0] = gyro[0] * m11 + gyro[1] * m12 + gyro[2] * m13;
	m_gyro[1] = gyro[0] * m21 + gyro[1] * m22 + gyro[2] * m23;
	m_gyro[2] = gyro[0] * m31 + gyro[1] * m32 + gyro[2] * m33;

	m_mag[0] = mag[0] * m11 + mag[1] * m12 + mag[2] * m13;
	m_mag[1] = mag[0] * m21 + mag[1] * m22 + mag[2] * m23;
	m_mag[2] = mag[0] * m31 + mag[1] * m32 + mag[2] * m33;

	// Accelerometer and Gyro offset compensation and estimation
	for (int i = 0; i < 3; i++) {
		m_accel[i] -= m_settings.accel_offsets[i];
		m_gyro[i] -= m_settings.gyro_offsets[i];

		if (m_settings.gyro_offset_comp_fact[i] > 0.0) {
			utils_step_towards(&m_gyro_offset[i], m_gyro[i], m_settings.gyro_offset_comp_fact[i] * dt);
			utils_truncate_number_abs(&m_gyro_offset[i], m_settings.gyro_offset_comp_clamp);
		} else {
			m_gyro_offset[i] = 0.0;
		}

		m_gyro[i] -= m_gyro_offset[i];
	}

	float gyro_rad[3];
	gyro_rad[0] = m_gyro[0] * M_PI / 180.0;
	gyro_rad[1] = m_gyro[1] * M_PI / 180.0;
	gyro_rad[2] = m_gyro[2] * M_PI / 180.0;

	switch (m_settings.mode) {
		case (AHRS_MODE_MADGWICK):
			ahrs_update_madgwick_imu(gyro_rad, m_accel, dt, (ATTITUDE_INFO *)&m_att);
			break;
		case (AHRS_MODE_MAHONY):
			ahrs_update_mahony_imu(gyro_rad, m_accel, dt, (ATTITUDE_INFO *)&m_att);
			break;
	}
}

static void terminal_gyro_info(int argc, const char **argv) {
	(void)argc;
	(void)argv;

	commands_printf("Gyro offsets: [%.3f %.3f %.3f]\n",
			(double)(m_settings.gyro_offsets[0] + m_gyro_offset[0]),
			(double)(m_settings.gyro_offsets[1] + m_gyro_offset[1]),
			(double)(m_settings.gyro_offsets[2] + m_gyro_offset[2]));
}

void rotate(float *input, float *rotation, float *output) {
	// Rotate imu offsets to match
	float s1 = sinf(rotation[2] * M_PI / 180.0);
	float c1 = cosf(rotation[2] * M_PI / 180.0);
	float s2 = sinf(rotation[1] * M_PI / 180.0);
	float c2 = cosf(rotation[1] * M_PI / 180.0);
	float s3 = sinf(rotation[0] * M_PI / 180.0);
	float c3 = cosf(rotation[0] * M_PI / 180.0);

	float m11 = c1 * c2;	float m12 = c1 * s2 * s3 - c3 * s1;	float m13 = s1 * s3 + c1 * c3 * s2;
	float m21 = c2 * s1;	float m22 = c1 * c3 + s1 * s2 * s3;	float m23 = c3 * s1 * s2 - c1 * s3;
	float m31 = -s2; 		float m32 = c2 * s3;				float m33 = c2 * c3;

	output[0] = input[0] * m11 + input[1] * m12 + input[2] * m13;
	output[1] = input[0] * m21 + input[1] * m22 + input[2] * m23;
	output[2] = input[0] * m31 + input[1] * m32 + input[2] * m33;
}

int8_t user_i2c_read(uint8_t dev_addr, uint8_t reg_addr, uint8_t *data, uint16_t len) {
	m_i2c_bb.has_error = 0;

	uint8_t txbuf[1];
	txbuf[0] = reg_addr;
	return i2c_bb_tx_rx(&m_i2c_bb, dev_addr, txbuf, 1, data, len) ? BMI160_OK : BMI160_E_COM_FAIL;
}

int8_t user_i2c_write(uint8_t dev_addr, uint8_t reg_addr, uint8_t *data, uint16_t len) {
	m_i2c_bb.has_error = 0;

	uint8_t txbuf[len + 1];
	txbuf[0] = reg_addr;
	memcpy(txbuf + 1, data, len);
	return i2c_bb_tx_rx(&m_i2c_bb, dev_addr, txbuf, len + 1, 0, 0) ? BMI160_OK : BMI160_E_COM_FAIL;
}

int8_t user_spi_read(uint8_t dev_id, uint8_t reg_addr, uint8_t *data, uint16_t len) {
	(void)dev_id;
	
	int8_t rslt = BMI160_OK; // Return 0 for Success, non-zero for failure 

	reg_addr = (reg_addr | BMI160_SPI_RD_MASK);

	chThdSleepMicroseconds(200); // #FIXME Wont work without this- Why?

	chMtxLock(&m_spi_bb.mutex);
	spi_bb_begin(&m_spi_bb);
	spi_bb_exchange_8(&m_spi_bb, reg_addr);
	spi_bb_delay();

	for (int i = 0; i < len; i++) {
		data[i] = spi_bb_exchange_8(&m_spi_bb, 0);
	}

	spi_bb_end(&m_spi_bb);
	chMtxUnlock(&m_spi_bb.mutex);
	return rslt;
}

int8_t user_spi_write(uint8_t dev_id, uint8_t reg_addr, uint8_t *data, uint16_t len) {
	(void)dev_id;

	int8_t rslt = BMI160_OK; /* Return 0 for Success, non-zero for failure */
	chMtxLock(&m_spi_bb.mutex);
	spi_bb_begin(&m_spi_bb);
	reg_addr = (reg_addr & BMI160_SPI_WR_MASK);
	spi_bb_exchange_8(&m_spi_bb, reg_addr);
	spi_bb_delay();

	for (int i = 0; i < len; i++) {
		spi_bb_exchange_8(&m_spi_bb, *data);
		data++;
	}

	spi_bb_end(&m_spi_bb);
	chMtxUnlock(&m_spi_bb.mutex);

	return rslt;
}