Hello all,

 

I am trying to interface with the MCP2515 on SPI2 of the RockPi4B on Armbian 22.08.6 Bullseye with Linux 5.15.74-rockchip64 and encountering some issues. 

 

The rockpi4B pins that I am using to connect to the MCP2515

INT - GPIO2_A7

MOSI - GPIO2_B2

MISO - GPIO2_B1

CLK - GPIO2_B3

CS - GPIO2_B4 

 

When using the overlay file that I have shown below, the output for "dmesg | grep mcp": 

[    6.662536] rockchip-pinctrl pinctrl: unable to find group for node mcp2515_int_pin

 

I have been able to get the MCP2515 to initialize successfully, but only if I comment out the pinctrl-0 reference to the mcp2515_int_pin in the overlay. Doing this I can bring up the device but I am only able to send/receive a few messages before candump shows it's not transmitting any messages until I bring down and up the can0 device where it will do the same thing. The interesting thing is, when the device doesn't communicate I can still see that the can0 device is still in the "Error-Active" mode, so theoretically I should still be able to interface with it. 

 

So, I am led to believe the issue I am encountering is due to that comment line to pinctrl-0 in the overlay. Just not sure of the solution to this. I have looked about just about every forum that makes reference to the MCP2515 and have not found any promising solutions. I have tried changing the target on fragment@0 to <&gpio>, <&gpio2>, etc. 

 

Here is a look at the DTS overlay I am using for the MCP2515:

//This devicetree overlay is used for RS485 CAN HAT.
/dts-v1/;
/plugin/;

/ {
        compatible = "rockchip,rockpi","rockchip,rk3399", "rockchip,rk3399-pinctrl";

        fragment@0 {
                target = <&pinctrl>;

                __overlay__ {
                        mcp2515_int_pin: mcp2515_int_pin {
                                rockchip,pins = <2 7 0 &pcfg_pull_none>;
                        };
                };
        };

        fragment@1 {
                target-path = "/";
                __overlay__ {
                        can_mcp2515_osc: can-mcp2515-osc {
                                compatible = "fixed-clock";
                                clock-frequency = <16000000>;
                                #clock-cells = <0>;
                        };
                };
        };

        fragment@2 {
                target = <&spi2>;

                __overlay__ {
                        status = "okay";
                        max-freq = <10000000>;
                        #address-cells = <1>;
                        #size-cells = <0>;

                        can_mcp2515: can-mcp2515@0 {
                                status = "okay";
                                compatible = "microchip,mcp2515";
                                reg = <0>;
                                interrupt-parent = <&gpio2>;
                                interrupts = <7 2 8>;
                                spi-max-frequency = <10000000>;
                                clocks = <&can_mcp2515_osc>;
                                vdd-supply = <&vcc3v3_sys>;
                                xceiver-supply = <&vcc3v3_sys>;
                                pinctrl-names = "default";
                                pinctrl-0 = <&mcp2515_int_pin>;
                        };
                };
        };
};

 

And my armbianEnv.txt: 

verbosity=1
bootlogo=false
overlay_prefix=rockchip
fdtfile=rockchip/rk3399-rock-pi-4b.dtb
rootdev=UUID=fa2cbc7c-56d1-448b-9ab3-fe864e21fbc5
rootfstype=ext4
overlays=spi-spidev
param_spidev_spi_bus=1
user_overlays=spi1-mcp2515-can0-overlay
usbstoragequirks=0x2537:0x1066:u,0x2537:0x1068:u

 

Here's a link to my armbianmonitor -u: https://paste.armbian.com/azameworos

 

I would like to mention I not very skilled with Linux based devices so please bear with me.

 

Any help would be greatly appreciated!

 

Best,

Austin

Hi @Austin Dubes,

did you find any solution?

Thanks

Edited April 6, 20233 yr by Anneress

I have the same issue. After I added an additional label in fragment@0 (I am using different pins):

fragment@0 {
        target = <&pinctrl>;

        __overlay__ {
            mcp2515 {
                mcp2515_int_pin: mcp2515_int_pin {
                rockchip,pins = <4 29 0 &pcfg_pull_none>;
                };
            };
        };        
    };

it can boot without problem.

But the behaviour is still the same, only a few CAN messages can be send.
 

My problem was solved, when I decreased the max spi frequency to 1000000. So my final dts is here:

What this will cause on transfer speed, I don't know.

 

//This devicetree overlay is used for mcp2515 CAN HAT.
/dts-v1/;
/plugin/;

/ {
	compatible = "rockchip,rockpi","rockchip,rk3399";

	fragment@0 {
		target = <&pinctrl>;

		__overlay__ {
			mcp2515_pins {
				mcp2515_int_pin: mcp2515_int_pin {
				rockchip,pins = <4 29 0 &pcfg_pull_none>;
				};
			};
		};		
	};

	fragment@1 {
		target-path = "/";

		__overlay__ {
			can_mcp2515_osc: can-mcp2515-osc {
				compatible = "fixed-clock";
				clock-frequency = <16000000>;
				#clock-cells = <0>;
			};
		};
	};

	fragment@2 {
		target = <&spi1>;

		__overlay__ {
			status = "okay";
			max-freq = <1000000>;
			#address-cells = <1>;
			#size-cells = <0>;

			can_mcp2515: can-mcp2515@0 {
				status = "okay";
				compatible = "microchip,mcp2515";
				reg = <0>;
				interrupt-parent = <&gpio4>;
				interrupts = <29 2>;
				spi-max-frequency = <1000000>;
				clocks = <&can_mcp2515_osc>;
				vdd-supply = <&vcc3v3_sys>;
				xceiver-supply = <&vcc3v3_sys>;
				pinctrl-names = "default";
				pinctrl-0 = <&mcp2515_int_pin>;
			};
		};
	};
};

 

spi1-mcp2515-can0-overlay.dts

Hi.

Somebody share working image.

 

In my case can0 don't create. 

 

$ dmesg | grep spi
[    2.359503] rockchip-spi ff1d0000.spi: registered master spi1
[    2.359902] spi spi1.0: setup mode 0, 8 bits/w, 10000000 Hz max --> 0
[    2.360579] rockchip-spi ff1d0000.spi: registered child spi1.0
[    2.360635] rockchip-spi ff1d0000.spi: chipselect 0 already in use
[    2.360650] spi_master spi1: spi_device register error /spi@ff1d0000/spidev
[    2.360696] spi_master spi1: Failed to create SPI device for /spi@ff1d0000/spidev

 

 lsmod | grep mcp
mcp251x                28672  0
can_dev                45056  1 mcp251x