Raspberry Pi device tree overlay for creating up to four CAN-Bus interfaces on spi0 using four MCP2515's

mcp2515-spi0-4cs-overlay.dts

/*
 * Device tree overlay for mcp251x on any spi interface by Kristian Sloth Lauszus.
 * Should be used with the "spi0-4cs" overlay.
 */

/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2835";

    /* disable spi-dev for spi0.0 if used */
    fragment@0 {
        target = <&spidev0>;
        __dormant__ {
            status = "disabled";
        };
    };

    /* disable spi-dev for spi0.1 if used */
    fragment@1 {
        target = <&spidev1>;
        __dormant__ {
            status = "disabled";
        };
    };

    /* disable spi-dev for spi0.2 if used */
    fragment@2 {
        target-path = "spi0/spidev@2";
        __dormant__ {
            status = "disabled";
        };
    };

    /* disable spi-dev for spi0.3 if used */
    fragment@3 {
        target-path = "spi0/spidev@3";
        __dormant__ {
            status = "disabled";
        };
    };

    /* the interrupt pin of the can-controller */
    fragment@4 {
        target = <&gpio>;
        __overlay__ {
            mcp2515_pins: mcp2515_pins {
                brcm,pins = <25>;
                brcm,function = <0>; /* input */
            };
        };
    };

    /* the clock/oscillator of the can-controller */
    fragment@5 {
        target-path = "/";
        __overlay__ {
            /* external oscillator of mcp2515 on spi0 */
            clk_mcp2515_osc: clk_mcp2515_osc {
                compatible = "fixed-clock";
                #clock-cells = <0>;
                clock-frequency  = <16000000>;
            };
        };
    };

    /* the spi config of the can-controller itself binding everything together */
    fragment@6 {
        target = <&spi0>;
        __overlay__ {
            /* needed to avoid dtc warning */
            #address-cells = <1>;
            #size-cells = <0>;
            mcp2515: mcp2515@0 {
                reg = <0>;
                compatible = "microchip,mcp2515";
                pinctrl-names = "default";
                pinctrl-0 = <&mcp2515_pins>;
                spi-max-frequency = <10000000>;
                interrupt-parent = <&gpio>;
                interrupts = <25 8>; /* IRQ_TYPE_LEVEL_LOW */
                clocks = <&clk_mcp2515_osc>;
            };
        };
    };

    __overrides__ {
        spi0-0 = <0>,"+0", /* enable fragment@0 */
                 <&mcp2515>,"reg:0=0",
                 <&mcp2515_pins>,"name=mcp2515_spi0_0_pins",
                 <&clk_mcp2515_osc>,"name=mcp2515-spi0-0-osc";
        spi0-1 = <0>,"+1", /* enable fragment@1 */
                 <&mcp2515>,"reg:0=1",
                 <&mcp2515_pins>,"name=mcp2515_spi0_1_pins",
                 <&clk_mcp2515_osc>,"name=mcp2515-spi0-1-osc";
        spi0-2 = <0>,"+2", /* enable fragment@2 */
                 <&mcp2515>,"reg:0=2",
                 <&mcp2515_pins>,"name=mcp2515_spi0_2_pins",
                 <&clk_mcp2515_osc>,"name=mcp2515-spi0-2-osc";
        spi0-3 = <0>,"+3", /* enable fragment@3 */
                 <&mcp2515>,"reg:0=3",
                 <&mcp2515_pins>,"name=mcp2515_spi0_3_pins",
                 <&clk_mcp2515_osc>,"name=mcp2515-spi0-3-osc";
        oscillator = <&clk_mcp2515_osc>,"clock-frequency:0";
        spimaxfrequency = <&mcp2515>,"spi-max-frequency:0";
        interrupt = <&mcp2515_pins>,"brcm,pins:0",<&mcp2515>,"interrupts:0";
    };
};

spi0-4cs-overlay.dts

/*
 * Device tree overlay for using 4 CS pins on spi0 by Kristian Sloth Lauszus.
 */

/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2835";

    fragment@0 {
        target = <&spi0>;
        frag0: __overlay__ {
            /* needed to avoid dtc warning */
            #address-cells = <1>;
            #size-cells = <0>;
            pinctrl-names = "default";
            pinctrl-0 = <&spi0_pins &spi0_cs_pins>;
            cs-gpios = <&gpio 8 1>, <&gpio 7 1>, <&gpio 6 1>, <&gpio 3 1>;
            status = "okay"; /* enable spi0 */

            spidev@2 {
                compatible = "spidev";
                reg = <2>;   /* CE2 */
                spi-max-frequency = <125000000>;
            };

            spidev@3 {
                compatible = "spidev";
                reg = <3>;   /* CE3 */
                spi-max-frequency = <125000000>;
            };
        };
    };

    fragment@1 {
        target = <&gpio>;
        __overlay__ {
            spi0_cs_pins: spi0_cs_pins {
                brcm,pins = <8 7 6 3>;
                brcm,function = <1>; /* out */
            };
        };
    };

    __overrides__ {
        cs0_pin = <&frag0>,"cs-gpios:4",
                  <&spi0_cs_pins>,"brcm,pins:0";
        cs1_pin = <&frag0>,"cs-gpios:16",
                  <&spi0_cs_pins>,"brcm,pins:4";
        cs2_pin = <&frag0>,"cs-gpios:28",
                  <&spi0_cs_pins>,"brcm,pins:8";
        cs3_pin = <&frag0>,"cs-gpios:40",
                  <&spi0_cs_pins>,"brcm,pins:12";
    };
};