Probe function for qspi is not called


I am using latest linux-socfpga with arria5.

The kernel does not detect any mtd device (qspi) on board.
The problem is that I don’t see that probe function for qspi is ever called…
Only if I change in dts file as following:
&qspi {
status = “okay”;

flash: flash@0 {
	#address-cells = <1>;
	#size-cells = <1>;
	-compatible = "n25q256a";
	+compatible = "cdns,qspi-nor";

than I finally get that cqspi_probe() and spi_npor_scan() are called:
[ 2.588663] cadence-qspi ff705000.spi: unrecognized JEDEC id bytes: ff ff ff ff ff ff
[ 2.604067] cadence-qspi ff705000.spi: Cadence QSPI NOR probe failed -2
[ 2.610805] cadence-qspi: probe of ff705000.spi failed with error -2

Should I change dts as I did ? Why does it fail to call probe with the original flash device name in dts ?