Nor flash using QSPI interface outputs max freq of 25 Mhz only.

[sandeep_yenugul]

Hi,

I am working on a custom board with Nor-flash over QSPI interface. I am able to read/write on flash PART winbond W25Q256JWPIQ.  I am trying to Run QSPI on 100 Mhz but not able to achieve it. How can I modify the QSPI freq.

I have set the maximum freq, in dts node 10MHz still get 25 Mhz.

[igorpadykov]

Hi sandeep

seems QSPI_CLK_ROOT set to default value given in Table 5-1. Clock Root Table

i.MX8MDQ Reference Manual
https://www.nxp.com/docs/en/reference-manual/IMX8MDQLQRM.pdf

So one can try to adjust it to other suitable values in

uboot/board/freescale/imx8mq_evk/imx8mq_evk.c

imx8mq_evk.c\imx8mq_evk\freescale\board - uboot-imx - i.MX U-Boot 

Best regards
igor
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[sandeep_yenugul]

Hi igorpadykov,

At u-boot it is already set to 100MHz, But I need steps to set 100 MHz at kernel side. So can you please share dts node or kernel changes for setting QSPI freq to 100Mhz. Below is my changes n dts and dtsi files.

dtsi file:

    qspi: qspi@30bb0000 {
        #address-cells = <1>;
        #size-cells = <0>;
        compatible = "fsl,imx7d-qspi";
        reg = <0 0x30bb0000 0 0x10000>, <0 0x08000000 0 0x10000000>;
        reg-names = "QuadSPI", "QuadSPI-memory";
        interrupts = <GIC_SPI 107 IRQ_TYPE_LEVEL_HIGH>;
        clocks = <&clk IMX8MQ_CLK_QSPI_ROOT>,
        <&clk IMX8MQ_CLK_QSPI_ROOT>;
        clock-names = "qspi_en", "qspi";
        status = "disabled";
    };

dts file:

&qspi {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_qspi>;
    status = "okay";

    flash0: w25q256@0 {
        reg = <0>;
        #address-cells = <1>;
        #size-cells = <1>;
        compatible = "sst,w25q256";
        spi-max-frequency = <100000000>;
        spi-nor,ddr-quad-read-dummy = <4>;
        status = "okay";
    };
};

[igorpadykov]

linux driver does not change frequency so no additional dts settings are

needed, in general you can try to debug it in qspi driver.

fsl-quadspi.c\spi-nor\mtd\drivers - linux-imx - i.MX Linux kernel 

linux clock driver

clk-imx8mq.c\imx\clk\drivers - linux-imx - i.MX Linux kernel 

Best regards
igor