Nitrogen6x spi out

[mmonto58]

Hello all, im using a Nitrogen6X-SOM along with the host board. Im trying to reconfigure the pinmuxing on it to enable spi out via this post: https://boundarydevices.com/mx6-device-tree-customization/

in the imx6qdl-nitrogen6x.dtsi i have made the following changes: (ECSPI1 was pre-existing and im addint that for reference, my modifications are the ECSPI2 sections)

pinctrl_ecspi1: ecspi1grp {

                fsl,pins = <

                        MX6QDL_PAD_EIM_D17__ECSPI1_MISO         0x100b1

                        MX6QDL_PAD_EIM_D18__ECSPI1_MOSI         0x100b1

                        MX6QDL_PAD_EIM_D16__ECSPI1_SCLK         0x000b1

#define GP_ECSPI1_NOR_CS        <&gpio3 19 GPIO_ACTIVE_LOW>

                        MX6QDL_PAD_EIM_D19__GPIO3_IO19          0x0b0b1

                >;

        };

        pinctrl_ecspi2: ecspi2grp {

                fsl,pins = <

                        MX6QDL_PAD_DISP0_DAT20__ECSPI2_SCLK     0x100b1

                        MX6QDL_PAD_DISP0_DAT21__ECSPI2_MOSI     0x100b1

                        MX6QDL_PAD_DISP0_DAT22__ECSPI2_MISO     0x100b1

                >;

        };

&ecspi1 {

        fsl,spi-num-chipselects = <1>;

        cs-gpios = GP_ECSPI1_NOR_CS;

        pinctrl-names = "default";

        pinctrl-0 = <&pinctrl_ecspi1>;

        status = "okay";

        flash: m25p80@0 {

                compatible = "sst,sst25vf016b";

                spi-max-frequency = <20000000>;

                reg = <0>;

                #address-cells = <1>;

                #size-cells = <1>;

                mtd@00000000 {

                        label = "U-Boot";

                        reg = <0x0 0xC0000>;

                };

                mtd@000C0000 {

                        label = "env";

                        reg = <0xC0000 0x2000>;

                };

                mtd@000C2000 {

                        label = "splash";

                        reg = <0xC2000 0x13e000>;

                };

        };

};

&ecspi2 {

        fsl,spi-num-chipselects = <1>;

        cs-gpios = <&gpio5 17 0>;

        pinctrl-names = "default";

        pinctrl-0 = <&pinctrl_ecspi2>;

        status = "okay";

        spidev@00 {

                compatible = "spidev";

                spi-max-frequency = <20000000>;

                reg = <0>;

        };

};

The issue im having is that on the 3 lines:

                        MX6QDL_PAD_DISP0_DAT20__ECSPI2_SCLK     0x100b1

                        MX6QDL_PAD_DISP0_DAT21__ECSPI2_MOSI     0x100b1

                        MX6QDL_PAD_DISP0_DAT22__ECSPI2_MISO     0x100b1

i get a syntax error on the ECSPI2. If i replace the ECSPI2 with ECSPI1 it compiles. I have checked every included .dts and .h and there are no other references to ECSPI1 that i could find, so there must be something wrong with my syntax in the .dtsi file but i cannot find where.

[gary_bisson]

Hi Matthew,

Every pin can only be muxed to a limited set of IP. You can't just decide which pin is going to be ECSPI2_CLK, this latter can be used from DISP0_DAT19, CSI0_DAT8 or EIM_CS0.

You need to read the i.MX6QD Reference Manual to learn the possible muxing.

Another tip, look at the kernel pinfunc header, it will give you all the possibilities:

linux-imx6/imx6q-pinfunc.h at boundary-imx_3.14.52_1.1.0_ga · boundarydevices/linux-imx6 · GitHub

Regards,

Gary

[mmonto58]

I see that i was able to get the muxing correct and i do see the signals go low at boot (which i would expect when it is setting up the dtb)

I do also see an additional interface that i didnt before in linux:

/sys/bus/spi/devices/0.0

/sys/bus/spi/devices/1.0

and

/dev/spidev1.0

Now what i am wondering is if there is any easy way to test/see some sample output through the device to ensure spi is being set up/muxed properly?

Under buildroot i did check the spidev and spi-tools options, but it doesnt actually seem like spi-tools is getting build into linux (not sure why, find . -name *spi*.* does not find any form of spitools).

[gary_bisson]

Hi Matthew,

There might be something wrong with your Buildroot. I just tried it here and building spi-tools provides:

- output/target/usr/bin/spi-config

- output/target/usr/bin/spi-pipe

You can look at the examples here on how to use those tools:

GitHub - cpb-/spi-tools: Simple command line tools to help using Linux spidev devices

Regards,

Gary

[qiang_li-mpu_se · Accepted solution]

Please check your hardware design, the pin MX6QDL_PAD_DISP0_DAT20 can't be used as ECSPI2_SCLK, the same case for the other two pins.

The valid function for ECSPI2:

ECSPI2_SCLK:     MX6QDL_PAD_EIM_CS0__ECSPI2_SCLK

                              MX6QDL_PAD_DISP0_DAT19__ECSPI2_SCLK

                              MX6QDL_PAD_CSI0_DAT8__ECSPI2_SCLK

ECSPI2_MOSI:     MX6QDL_PAD_EIM_CS1__ECSPI2_MOSI

                              MX6QDL_PAD_DISP0_DAT16__ECSPI2_MOSI

                              MX6QDL_PAD_CSI0_DAT9__ECSPI2_MOSI

ECSPI2_MISO:     MX6QDL_PAD_EIM_OE__ECSPI2_MISO

                              MX6QDL_PAD_DISP0_DAT17__ECSPI2_MISO

                              MX6QDL_PAD_CSI0_DAT10__ECSPI2_MISO