Questions about spi read and write function mapping

[June6]

I'm having trouble driving the BMI088 with the official driver of Bosch BMI088 (link to this driver) in the ble_app_uart routine. I never get the chip ID. Bosch BMI088 official driver link address: https://github.com/BoschSensortec/BMI08x-Sensor-API . The spi read and write functions are encapsulated into the following two APIs: 

int8_t user_spi_write(uint8_t cs_pin, uint8_t reg_addr, uint8_t *data, uint16_t len);

int8_t user_spi_read(uint8_t cs_pin, uint8_t reg_addr, uint8_t *data, uint16_t len);

So How can I map these two APIs into Nordic operation functions？ 

  

And The automatic selection between [CPOL = '0' and CPHA = '0'] and [CPOL = '1' and CPHA = '1'] is controlled based on the value of SCK after a falling edge of CSB (1 or 2). What SPI mode should I configure？

[June6]

My approach is as follows:

int8_t user_spi_read(uint8_t cs_pin, uint8_t reg_addr, uint8_t *data, uint16_t len)
{
    nrf_gpio_pin_clear(cs_pin);
    nrf_delay_us(1);
    if(len<=255)
    {
        uint8_t m_tx_buf[1] = {0};
        uint8_t m_tx_length = 1;
        uint8_t m_rx_length = (uint8_t)len;
        m_tx_buf[0] = reg_addr;

        // Reset rx buffer and transfer done flag
        memset(m_rx_buf, 0, m_rx_length);
        spi_xfer_done = false;

        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_tx_length, m_rx_buf, m_rx_length));
        while (!spi_xfer_done)
        {
            __WFE();
        }
        memcpy_fast(data, m_rx_buf, m_rx_length);
    }
    else
    {
        NRF_LOG_DEBUG("Spi read over length.");
    }
    nrf_delay_us(1);
    nrf_gpio_pin_set(cs_pin);
}


int8_t user_spi_write(uint8_t cs_pin, uint8_t reg_addr, uint8_t *data, uint16_t len)
{
    nrf_gpio_pin_clear(cs_pin);
    nrf_delay_us(1);
    if(len<=255)
    {
        uint8_t m_tx_buf[255] = {0};
        uint8_t m_length = (uint8_t)len;
        m_tx_buf[0] = reg_addr;
        memcpy(&m_tx_buf[1], data, strlen(data));
  
        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));
    }
    else
    {
        NRF_LOG_DEBUG("Spi write over length.");
    }
    nrf_delay_us(1);
    nrf_gpio_pin_set(cs_pin);
}

[June6]

SPI timing is 

[June6]

I try to call bmi08a_init, there is an operation to read the chip ID in this function, but the value read is always 0xFF, (correct 0x1E). Where am I wrong about the mapping of SPI reads and writes?

[June6]

I have solved the above problem.