I am trying to put the CAN interface on a riscv computer, and it is taking some time. What I thought is to put a rpi working, and replicate the work on the other system. Here is the configuration that is being followed:

Overlay

part of soc ..

spi@7e204000 {
    compatible = "brcm,bcm2835-spi";
    clocks = <0x08 0x14>;
    status = "okay";
    #address-cells = <0x01>;
    interrupts = <0x02 0x16>;
    cs-gpios = <0x07 0x08 0x01 0x07 0x07 0x01>;
    #size-cells = <0x00>;
    dma-names = "tx\0rx";
    phandle = <0x22>;
    reg = <0x7e204000 0x200>;
    pinctrl-0 = <0x0e 0x0f>;
    dmas = <0x0b 0x06 0x0b 0x07>;
    pinctrl-names = "default";

    spidev@1 {
        compatible = "spidev";
        #address-cells = <0x01>;
        #size-cells = <0x00>;
        phandle = <0x6b>;
        reg = <0x01>;
        spi-max-frequency = <0x7735940>;
    };

    mcp2515@0 {
        compatible = "microchip,mcp2515";
        clocks = <0x8e>;
        interrupt-parent = <0x07>;        // THIS IS GPIO
        interrupts = <0x19 0x08>;         // The first is 25 dec, that is the interrupt associated with the spi0.0. The second I think is something related to interrupts
        phandle = <0x8f>;
        reg = <0x00>;
        pinctrl-0 = <0x8d>;
        spi-max-frequency = <0x989680>;
        pinctrl-names = "default";
    };

    spidev@0 {
        compatible = "spidev";
        status = "disabled";
        #address-cells = <0x01>;
        #size-cells = <0x00>;
        phandle = <0x6a>;
        reg = <0x00>;
        spi-max-frequency = <0x7735940>;
    };
};

part of /

can0_osc {
    compatible = "fixed-clock";
    #clock-cells = <0x00>;
    phandle = <0x8e>;
    clock-frequency = <0x7a1200>;
};

part of gpio

gpio@7e200000 {
			compatible = "brcm,bcm2835-gpio";
			gpio-line-names = "A lot of text";
			gpio-controller;
			gpio-ranges = <0x07 0x00 0x00 0x36>;
			#interrupt-cells = <0x02>;
			interrupts = <0x02 0x11 0x02 0x12>;
			phandle = <0x07>;
			reg = <0x7e200000 0xb4>;
			#gpio-cells = <0x02>;
			pinctrl-names = "default";
			interrupt-controller;
            
            SOME USELESS CODE HERE
            
            can0_pins {
				brcm,pins = <0x19>;
				phandle = <0x8d>;
				brcm,function = <0x00>;
			};

Pinmux

pin 25 (gpio25): spi0.0 (GPIO UNCLAIMED) function gpio_in group gpio25

Interrupts

160: 252 pinctrl-bcm2835 25 Level spi0.0

Overlay

/*
 * Device tree overlay for mcp251x/can0 on spi0.0
 */

/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";
    /* disable spi-dev for spi0.0 */
    fragment@0 {
        target = <&spi0>;
        __overlay__ {
            status = "okay";
            spidev@0{
                status = "disabled";
            };
        };
    };

    /* the interrupt pin of the can-controller */
    fragment@1 {
        target = <&gpio>;
        __overlay__ {
            can0_pins: can0_pins {
                brcm,pins = <25>;
                brcm,function = <0>; /* input */
            };
        };
    };

    /* the clock/oscillator of the can-controller */
    fragment@2 {
        target-path = "/clocks";
        __overlay__ {
            /* external oscillator of mcp2515 on SPI0.0 */
            can0_osc: can0_osc {
                compatible = "fixed-clock";
                #clock-cells = <0>;
                clock-frequency  = <16000000>;
            };
        };
    };

    /* the spi config of the can-controller itself binding everything together */
    fragment@3 {
        target = <&spi0>;
        __overlay__ {
            /* needed to avoid dtc warning */
            #address-cells = <1>;
            #size-cells = <0>;
            can0: mcp2515@0 {
                reg = <0>;
                compatible = "microchip,mcp2515";
                pinctrl-names = "default";
                pinctrl-0 = <&can0_pins>;
                spi-max-frequency = <10000000>;
                interrupt-parent = <&gpio>;
                interrupts = <25 0x2>;
                clocks = <&can0_osc>;
            };
        };
    };
    __overrides__ {
        oscillator = <&can0_osc>,"clock-frequency:0";
        spimaxfrequency = <&can0>,"spi-max-frequency:0";
        interrupt = <&can0_pins>,"brcm,pins:0",<&can0>,"interrupts:0";
    };
};