Zephyr SPIM does not receive any data from MISO pin

Question

Hello, 
 
 I'm trying to move from nRF5 SDK with nRF52840 to NCS with nRF5340 and experiencing a lot of problems replacing the nrf driver functions with nrfx. 
 
 Thanks to the other precedents in the devzone, I implemented all the functions except the SPIM Rx. 
 
 The problem is that I see the SPI slave (nRF52840-DK and I checked it works well with another nRF52840-DK) toggles the MISO pin, but the SPI master (nRF5340) cannot read the input. 
 
 Following is the code how I configured the SPIM. 
 
 nrfx_spim_t spim_adc = NRFX_SPIM_INSTANCE(2);
#define spim_adc_m_length 240
static uint8_t spim_adc_rx_buf[spim_adc_m_length+1];
nrfx_spim_xfer_desc_t spim_adc_desc = NRFX_SPIM_XFER_RX(spim_adc_rx_buf, spim_adc_m_length);
static volatile bool spim_adc_xfer_done;

(...)

void gpiote_handler(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
	nrfx_err_t err_code = nrfx_spim_xfer(&spim_adc, &spim_adc_desc, 0);
}

void gpiote_init(void)
{
	nrfx_err_t err_code;
	
 err_code = nrfx_gpiote_init(6);

	nrfx_gpiote_in_config_t gpiote_cfg = NRFX_GPIOTE_CONFIG_IN_SENSE_LOTOHI(false);

	err_code = nrfx_gpiote_in_init(pin_spim_fpga_ind, &gpiote_cfg, gpiote_handler);
	if (NRFX_SUCCESS != err_code)
	{
 printk("Init error
");
	}
	nrfx_gpiote_in_event_enable(pin_spim_fpga_ind, true);
}

(...)

void spim_adc_event_handler(nrfx_spim_evt_t const *p_event, void *p_context)
{
	if (p_event->type == NRFX_SPIM_EVENT_DONE)
	{
 spim_adc_xfer_done = true;
	}
}

void spi_init(void)
{
	nrfx_spim_config_t spim_adc_config = NRFX_SPIM_DEFAULT_CONFIG(pin_spim_adc_CLK, pin_spim_adc_MOSI, pin_spim_adc_MISO, pin_spim_adc_CS);
	spim_adc_config.frequency = NRF_SPIM_FREQ_8M;
	spim_adc_config.mode = NRF_SPIM_MODE_3;
	// nrfx_spim_init(&spim_adc, &spim_adc_config, spim_adc_event_handler, NULL);
	if (NRFX_SUCCESS != nrfx_spim_init(&spim_adc, &spim_adc_config, spim_adc_event_handler, NULL))
	{
 printk("Init error
");
	}
	IRQ_DIRECT_CONNECT(SPIM2_SPIS2_TWIM2_TWIS2_UARTE2_IRQn, 2, nrfx_spim_2_irq_handler, 0);
	irq_enable(SPIM2_SPIS2_TWIM2_TWIS2_UARTE2_IRQn);
}

(...)

void main(void)
{
	// Set CPU clock to 64 MHz
	HFCLKCTL_R &= ~(0x01);

	// Init
	ble_init();
	nus_init();
	gpio_pin_init();
	spi_init();
	gpiote_init();

	// Load configuration
	if (IS_ENABLED(CONFIG_SETTINGS)) {
 settings_load();
	}

	// Start BLE advertising
	advertising_init();
	
	// Enable cache and hit/miss tracking
 while((NVMC_READY_R&0x1) == 0);
 NVMC_ICACHECNF_R = 0x101;

	// Main loop responses to the BLE RX event after the callback
	for(;;)
	{
 if (spim_adc_xfer_done)
 {
 uint16_t length = spim_adc_m_length;
 bt_nus_send(NULL, spim_adc_rx_buf, length);
 spim_adc_xfer_done = false;
 }
	}
} 
 
 As you can see, when the SPI transaction is over, I send the Rx buffer data via Bluetooth. The result is a 240 bytes length array with only zero value. 
 
 Please let me know if I missed something required to enable SPI Rx.

P.S. The code crashes when I locate the bt_nus_data_send() in the SPIM handler but there was no problem doing so with ble_nus_data_send(). Is this the problem of priority which was managed by SoftDevice before?