Dtsi changes for dual flash in flexispi of imx8mp verdin

Technical Support
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1

Hello!
I have interfaced the flexispi (QSPI) controller with two qspi flash devices using A_SS0_B and GPIO3_16.
First flash got detected as expected but 2nd flash is not detected but got ‘spi-nor spi0.1: unrecognized JEDEC id bytes: 00 00 00 00 00 00’ so would like to confirm that my dts changes are okay. Do I need to specify the 2nd flash CS since its only through GPIO.
What could be the issue here ? dts or problem can be hw ?

I found this in imx8mp Verdin SOM datasheet.

The Verdin standard offers one QuadSPI channel with two chip selects for up to two memory
devices in the “Reserved” pin class. However, only the first chip select pin is available from the
FlexSPI controller. The second chip select pin on the module edge connector is a regular GPIO.
Therefore, the support for dual device memory is limited.

&flexspi {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_flexspi0>;
	//cs-gpios = <&gpio3 1 GPIO_ACTIVE_LOW>, <&gpio3 16 GPIO_ACTIVE_LOW>;
	status = "okay";

	flash0: s70fl01gs@0 {
		#address-cells = <1>;
		#size-cells = <1>;
		compatible = "cypress,s70fl01gs", "jedec,spi-nor";
		reg = <0>;
		spi-max-frequency = <40000000>;
		spi-nor,ddr-quad-read-dummy = <6>;
		spi-tx-bus-width = <4>;
		spi-rx-bus-width = <4>;
		status = "okay";
	};
	
	flash1: s70fl01gs@1 {
		#address-cells = <1>;
		#size-cells = <1>;
		compatible = "cypress,s70fl01gs", "jedec,spi-nor";
		reg = <1>;
		spi-max-frequency = <40000000>;
		spi-nor,ddr-quad-read-dummy = <6>;
		spi-tx-bus-width = <4>;
		spi-rx-bus-width = <4>;
		status = "okay";
	};
};
	pinctrl_flexspi0: flexspi0grp {
		fsl,pins = <
			MX8MP_IOMUXC_NAND_ALE__FLEXSPI_A_SCLK		0x1c2	/* SODIMM 52 */
			MX8MP_IOMUXC_NAND_CE0_B__FLEXSPI_A_SS0_B	0x82	/* SODIMM 54 */
			MX8MP_IOMUXC_NAND_READY_B__GPIO3_IO16		0x82	/* SODIMM 64 */
			MX8MP_IOMUXC_NAND_DQS__FLEXSPI_A_DQS		0x82	/* SODIMM 66 */
			MX8MP_IOMUXC_NAND_DATA00__FLEXSPI_A_DATA00	0x82	/* SODIMM 56 */
			MX8MP_IOMUXC_NAND_DATA01__FLEXSPI_A_DATA01	0x82	/* SODIMM 58 */
			MX8MP_IOMUXC_NAND_DATA02__FLEXSPI_A_DATA02	0x82	/* SODIMM 60 */
			MX8MP_IOMUXC_NAND_DATA03__FLEXSPI_A_DATA03	0x82	/* SODIMM 62 */
		>;
	};
2

Hi @titusece ,

iMX8MP SoC supports 2 QSPI and upto 4 device can be connected. However, one one QSPI is available on the Colibri iMX8MP.
Also, only the first chip (A_SS0_B) select pin is available from the FlexSPI controller. The second chip select pin on the module edge connector is a regular GPIO. Therefore, the support for dual device memory is limited.
The following image is from NXP IMX8MP reference manual.
image

In your case, are you connecting one flash to QSPI and other to regular SPI (ECSPI) ?

3

Thanks for your reply.

In your case, are you connecting one flash to QSPI and other to regular SPI (ECSPI) ?
No, we connected two QSPI flash into QSPI interface (flexspi) and ECSPI is used for other purpose.

We have interfaced two QSPI flash chips into imx8mp’s flexspi controller.
You can see in our dts code changes that two entries are present for both flash chips.

Also, only the first chip (A_SS0_B) select pin is available from the FlexSPI controller. The second chip select pin on the module edge connector is a regular GPIO. Therefore, the support for dual device memory is limited.

I didn’t get this one, I can’t interface two QSPI flash into flexspi on IMX8MP SOM ? thats called limitation ?
In our schematics, we connected first QSPI’s CS pin to A_SS0_B pin and 2nd QSPI’s CS pin to ’ NAND_READY_B__GPIO3_IO16’ in our custom board.
Is this okay and can be done ? also dts code is okay for that design ?
Thank you.

4

Hi @titusece ,

Can you please share your schematic, how you are interfacing flash to QSPI?
Also please share complete dmesg log to further check.

Additionally can you please try adding below fields in flexspi node and see if you are able to detect

num-cs = <2>;
cs-gpios = <&gpio3 1 GPIO_ACTIVE_LOW>, <&gpio3 16 GPIO_ACTIVE_LOW>;

Modify cs pin as per your connection and also make sure second cs pin is not used at any other place.

Best Regards
Ritesh Kumar