working_imu.c

#include <stdint.h>
#include <string.h>

#include "app_timer.h"
#include "nrf_delay.h"
#include "nrf_drv_twi.h"
#include "nrf_gpio.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#include "lsm9ds1.h"

void app_error_fault_handler(uint32_t id, uint32_t pc, uint32_t info)
{
    nrf_gpio_pin_set(4);

    NRF_BREAKPOINT_COND;

    for (;;) {}
}

void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name)
{
    app_error_handler(0xDEADBEEF, line_num, p_file_name);
}

static void timers_init(void)
{
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
}

static void log_init(void)
{
    ret_code_t err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();
}

static const nrf_drv_twi_t twi = NRF_DRV_TWI_INSTANCE(0);

static void twi_init()
{
    const nrf_drv_twi_config_t config = {
        .scl                = 8,
        .sda                = 7,
        .frequency          = NRF_DRV_TWI_FREQ_100K,
        .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
        .clear_bus_init     = false
    };

    int ret = nrf_drv_twi_init(&twi, &config, NULL, NULL);
    APP_ERROR_CHECK(ret);

    nrf_drv_twi_enable(&twi);
}

lsm9ds1_t imu;

static void lsm9ds1_test()
{
    lsm9ds1_init(&imu, &twi);

    while (1)
    {
        int16_t accel_x, accel_y, accel_z;

        lsm9ds1_accel_read_all(&imu, &accel_x, &accel_y, &accel_z);

        NRF_LOG_INFO("Got reading: accel_x %d", accel_x);
        NRF_LOG_INFO("Got reading: accel_y %d", accel_y);
        NRF_LOG_INFO("Got reading: accel_z %d", accel_z);

        NRF_LOG_FLUSH();

        nrf_delay_ms(20);
    }
}

int main(void)
{
    nrf_gpio_cfg_output(4);

    // Initialize.
    log_init();
    timers_init();

    // Start execution.
    NRF_LOG_INFO("Hello, world!");

    twi_init();
    NRF_LOG_INFO("TWI successfullly initialized.");

    lsm9ds1_test();
}

What lsm9ds1.h file was being used for this?