TDA2PXEVM: Using QSPI as standart SPI to communicate with CAN-bus transceiver

Part Number: TDA2PXEVM

Hello there.

I want to use QSPI as standart 4-wire SPI to communicate with TLE9255W CAN-bus transceiver in full duplex mode using Linux spidev driver. I have dra76-evm-infoadas.dts modified this way:

&qspi {
    status = "okay";
    reg = <0x4b300000 0x100>,
          <0x5c000000 0x4000000>,
          <0x4a002558 0x4>;
    spi-max-frequency = <100000>;
    reg-names = "qspi_base", "qspi_mmap", "qspi_ctrlmod";
    /delete-node/ m25p80@0;
    spidev@0x00 {
        compatible = "rohm,dh2228fv";
        reg = <0>;
        status = "okay";
        spi-max-frequency = <100000>;
        spi-cpha;
    };
};

Thus when I have spidev module loaded I get /dev/spidev32766.0 device to work with.

Whe I run spidev_test application (compiled from linux kernel sources) I got EINVAL error, because this application tries to use /dev/spidev32766.0 in full duplex mode, but ti-qspi driver in it's probe function cofigures itself as follow:

master->flags = SPI_MASTER_HALF_DUPLEX;

Even if I have this line commented out -- there is another place in code:

static int qspi_transfer_msg(struct ti_qspi *qspi, struct spi_transfer *t,
			     int count)
{
	int ret;

	if (t->tx_buf) {
		ret = qspi_write_msg(qspi, t, count);
		if (ret) {
			dev_dbg(qspi->dev, "Error while writing\n");
			return ret;
		}
	}

	if (t->rx_buf) {
		ret = qspi_read_msg(qspi, t, count);
		if (ret) {
			dev_dbg(qspi->dev, "Error while reading\n");
			return ret;
		}
	}

	return 0;
}

And on SPI bus I got two transactions:

Because CAN-bus transceiver works only in full-duplex mode I can't get it's answer to me.

So I have two questions about this all:

1) Is there any hardware limitation in QSPI controller to use full duplex?

2) If there is no hardware limitations -- how can I enable full duplex mode for QSPI?