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TCAN4550EVM: Connecting TCAN4550 to Raspberry Pi

Nathan Wagenbach
Prodigy 60 points
Part Number: TCAN4550EVM
Other Parts Discussed in Thread: TCAN4550

I am tring to connect the TCAN4550 tothe Raspberry Pi 3B+  and I can't seem to figure out the process to get the linux driver working. I have updated the kernel to 5.4.42 so as far as I can tell the driver should be built in but I cannot figure out how to actually communicate with the TCAN4550. Any help would be greatly appreciated.

  • 0
    TI__Mastermind 29390 points

    Hi Nathan,

    Have you setup the device tree bindings for the TCAN4x5x interface for your board?

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Prodigy 60 points

    I have not setup the device tree bindings. I am attempting to follow the instructions at https://www.raspberrypi.org/documentation/configuration/device-tree.md for implementing a new device tree binding but when I try to use the dtc command on the .dts file I created containing the example tcan4x5x that you posted I get an error that dtc is unable to parse the input tree. Thanks for your help,

    Nathan

  • 0 in reply to Nathan Wagenbach
    TI__Mastermind 29390 points

    The device tree bindings in the example are specific to the processor used and the GPIO lines that will be used.  You will need to adjust these for your specific application and hardware.  I would suggest following another Raspberry Pi example of a device tree binging for GPIO lines and SPI to help determine what modifications may be necessary.  The TCAN4x5x device tree bindings were based on a TI Processor and not a Raspberry Pi.

    Also, could you post specific error messages you receive to help us better understand the specific problems you are facing and help us provide more specific suggestions on a possible solution.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Prodigy 60 points

    Okay, I think I'm moving closer to having a fix but I'm not there yet. I have adapted https://github.com/Ysurac/raspberry_kernel_mptcp/blob/master/arch/arm/boot/dts/overlays/mcp2515-can0-overlay.dts to fit with the tcan4x5x device tree bindings resulting in this dts file. 

    /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";
        };
    };

    fragment@1 {
		target = <&spidev0>;
		__overlay__ {
			status = "disabled";
		};
    };

    /* the interrupt pin of the can-controller */
    fragment@2 {
        target = <&gpio>;
        __overlay__ {
            tcan4x5x_pins: tcan4x5x_pins {
                brcm,pins = <25>;
                brcm,function = <0>; /* input */
            };
        };
    };

    /* the spi config of the can-controller itself binding everything together */
    fragment@4 {
        target = <&spi0>;
        __overlay__ {
            /* needed to avoid dtc warning */
            #address-cells = <1>;
            #size-cells = <1>;
            tcan4x5x: tcan4x5x@0 {
                compatible = "ti,tcan4x5x";
                reg = <0>;
                pinctrl-names = "default";
                pinctrl-0 = <&tcan4x5x_pins>;
                spi-max-frequency = <10000000>;
                bosch,mram-cfg = <0x0 0 0 32 0 0 1 1>;
                interrupt-parent = <&gpio>;
                interrupts = <25 0x2>;
            };
        };
    };
    __overrides__ {
        oscillator = <&tcan4x5x_osc>,"clock-frequency:0";
        spimaxfrequency = <&tcan4x5x>,"spi-max-frequency:0";
        interrupt = <&tcan4x5x_pins>,"brcm,pins:0",<&tcan4x5x>,"interrupts:0";
    };
};

    I then compiled this dts file into a dtbo file and placed it into /boot/overlays on the raspberry pi. Is there anything else I need to do? I don't get any errors as far as I can tell but I cant find how to access the tcan4450 even with the device tree binding hopefully working.

    Thanks,

    Nathan

  • 0 in reply to Nathan Wagenbach
    Prodigy 60 points

    Can anyone verify my dts file is setup correctly, Any help would be greatly appreciated.

    Thanks,

    Nathan

  • 0 in reply to Nathan Wagenbach
    TI__Mastermind 29390 points

    Hi Nathan,

    I'm sorry for the delay and overlooking your previous post.  I will review the file you provided and follow up shortly.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    TI__Mastermind 29390 points

    Hi Nathan,

    I didn't see anything that I thought was a problem with your DTS file and I checked with our developer as well.  If it doesn't give any compile errors, there isn't much more we can say about it without boot logs that might show something different.

    In order to to access the TCAN4550, you will need to download and build the Linux CAN Utils https://github.com/linux-can/can-utils.  This provides the interface to the CAN device and to send and receive packets.  This was how the driver was developed and tested and you can view the CAN interfaces through this IP.

    Here is a wiki you can use as a general reference for this. https://developer.ridgerun.com/wiki/index.php/How_to_configure_and_use_CAN_bus

    Once you have the can-utils IP loaded, our developer provided me with a list of some commands he used during the development and verification that you can use a reference to get started:

    Sends a message non FD message

    ./ip link set can0 up type can bitrate 500000
    ./cansend can0 123#DEADBEEF

    Receives messages

    ./candump -a can0

    Sets up CAN FD and generates numerous packets

    ./ip link set can0 up type can bitrate 500000 dbitrate 2000000 fd on

    ./cangen can0 -g 0 -p 3 -i -f -e  &

    Below stops cangen from sending packets

    kill $(ps ax | grep -m 1 cangen | awk '{print$1}')

    shows CAN interface

    ./ip -d link show can0

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Prodigy 60 points

    I don't get any errors when I comple the device tree overlay but I also cant find any references to can being started in the boot logs. Would I get errors if my device tree overlay was setup incorrectly or would it just fail silently? I have attached both my boot log and my config.txt to see if there is anything going obvously wrong.

    Thanks for your help,

    Nathan

    config.txt
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    # For more options and information see
    # http://rpf.io/configtxt
    # Some settings may impact device functionality. See link above for details
    # uncomment if you get no picture on HDMI for a default "safe" mode
    #hdmi_safe=1
    # uncomment this if your display has a black border of unused pixels visible
    # and your display can output without overscan
    disable_overscan=1
    # uncomment the following to adjust overscan. Use positive numbers if console
    # goes off screen, and negative if there is too much border
    #overscan_left=16
    #overscan_right=16
    #overscan_top=16
    #overscan_bottom=16
    # uncomment to force a console size. By default it will be display's size minus
    # overscan.
    #framebuffer_width=1280
    #framebuffer_height=720
    # uncomment if hdmi display is not detected and composite is being output
    #hdmi_force_hotplug=1
    # uncomment to force a specific HDMI mode (this will force VGA)
    #hdmi_group=1
    #hdmi_mode=1
    # uncomment to force a HDMI mode rather than DVI. This can make audio work in
    # DMT (computer monitor) modes
    #hdmi_drive=2
    # uncomment to increase signal to HDMI, if you have interference, blanking, or
    # no display
    #config_hdmi_boost=4
    # uncomment for composite PAL
    #sdtv_mode=2
    #uncomment to overclock the arm. 700 MHz is the default.
    #arm_freq=800
    # Uncomment some or all of these to enable the optional hardware interfaces
    dtparam=i2c_arm=on,i2c_arm_baudrate=400000
    #dtparam=i2s=on
    #dtparam=spi=on
    # Uncomment this to enable infrared communication.
    #dtoverlay=gpio-ir,gpio_pin=17
    #dtoverlay=gpio-ir-tx,gpio_pin=18
    # Additional overlays and parameters are documented /boot/overlays/README
    # Enable audio (loads snd_bcm2835)
    dtparam=audio=on
    [pi4]
    # Enable DRM VC4 V3D driver on top of the dispmanx display stack
    dtoverlay=vc4-fkms-v3d
    max_framebuffers=2
    [all]
    #dtoverlay=vc4-fkms-v3d
    dtparam=spi=on
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    boot_log.txt
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    [ 0.000000] Booting Linux on physical CPU 0x0
    [ 0.000000] Linux version 5.4.42-v7+ (dom@buildbot) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611)) #1319 SMP Wed May 20 14:06:11 BST 2020
    [ 0.000000] CPU: ARMv7 Processor [410fd034] revision 4 (ARMv7), cr=10c5383d
    [ 0.000000] CPU: div instructions available: patching division code
    [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
    [ 0.000000] OF: fdt: Machine model: Raspberry Pi 3 Model B Plus Rev 1.3
    [ 0.000000] Memory policy: Data cache writealloc
    [ 0.000000] Reserved memory: created CMA memory pool at 0x37400000, size 64 MiB
    [ 0.000000] OF: reserved mem: initialized node linux,cma, compatible id shared-dma-pool
    [ 0.000000] On node 0 totalpages: 242688
    [ 0.000000] Normal zone: 1896 pages used for memmap
    [ 0.000000] Normal zone: 0 pages reserved
    [ 0.000000] Normal zone: 242688 pages, LIFO batch:63
    [ 0.000000] percpu: Embedded 20 pages/cpu s49792 r8192 d23936 u81920
    [ 0.000000] pcpu-alloc: s49792 r8192 d23936 u81920 alloc=20*4096
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

  • 0 in reply to Nathan Wagenbach
    TI__Mastermind 29390 points

    Hi Nathan,

    It appears we would need the .config built from the defconfig from the kernel build instead of the config.txt because it has nothing for the TCAN device.  If you can provide that, we can review it.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    TI__Mastermind 29390 points

    Hi Nathan,

    Also, make sure you have this in your defconfig when you build.  This will tell the compiler to compile the driver.  Our developer was not seeing any messages associated with either.

    CONFIG_CAN_M_CAN=y

    CONFIG_CAN_M_CAN_TCAN4X5X=y

    Or if you want them as modules:

    CONFIG_CAN_M_CAN=m

    CONFIG_CAN_M_CAN_TCAN4X5X=m

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Prodigy 60 points

    This is the .config file from building the kernel. I added those lines that you gave me but I still cannot seem to find any reference to where m_can or the tcan4x5x driver are being started by the system.

    my.config

  • 0 in reply to Nathan Wagenbach
    TI__Mastermind 29390 points

    Hi Nathan,

    The only thing our developer can think of is that maybe you did not copy the modules to the device and you could try to use them built-in as opposed to modules.  He suggested to try the following:

    CONFIG_CAN_M_CAN=y

    CONFIG_CAN_M_CAN_TCAN4X5X=y

    Regards

    Jonathan