sCAN CAN shim driver

This driver integrates the sCAN soft peripheral with the Zephyr CAN API, enabling control over the peripheral. This allows for using the sCAN soft peripheral with higher layer zephyr libraries like ISO-TP Transport Protocol and socket_can, external modules like CANnectivity USB to CAN adapter firmware, the CAN shell CAN Shell, along with any native zephyr applications/samples like zephyr/samples/drivers/can.

Configuration

The sCAN CAN shim driver is defined in the devicetree using the nordic,nrf-scan. The following example is for the nRF54L15DK

&pinctrl {
        scan_default: scan_default {
                group1 {
                        psels = <NRF_PSEL(SDP_MSPI_DQ1, 2, 2)>; /* TX */
                        nordic,drive-mode = <NRF_DRIVE_S0S1>;
                        bias-pull-up;
                };

                group2 {
                        psels = <NRF_PSEL(SDP_MSPI_DQ3, 2, 4)>; /* RX */
                        nordic,drive-mode = <NRF_DRIVE_S0S1>;
                        bias-disable;
                };
        };

        scan_sleep: scan_sleep {
                group1 {
                        low-power-enable;
                        psels = <NRF_PSEL(SDP_MSPI_DQ0, 2, 2)>,
                                <NRF_PSEL(SDP_MSPI_DQ1, 2, 4)>;
                        bias-pull-up;
             };
        };
};

&spi00 {
        status = "disabled";
};

&cpuflpr_vpr {
        pinctrl-0 = <&scan_default>;
        pinctrl-1 = <&scan_sleep>;
        pinctrl-names = "default", "sleep";
        interrupts = <76 NRF_DEFAULT_IRQ_PRIORITY>;
        status = "okay";
        /delete-property/ execution-memory;
};

/ {
        soc {
                softperiph_ram: memory@2003b400 {
                        reg = <0x2003b400 0x4400>;
                        ranges = <0 0x2003b400 0x4400>;
                        #address-cells = <1>;
                        #size-cells = <1>;

                        scan: scan@4200 {
                                compatible = "nordic,nrf-scan";
                                #address-cells = <1>;
                                #size-cells = <0>;
                                reg = <0x4200 0x200>;
                        };
                };
        };
};

More example devicetree overlays can be found in the board overlays for the tests in nrf/tests/zephyr/drivers/can/. Relevant porting information regarding RAM layout and pin configuration can be found here sCAN nRF54L Series porting guide.

To configure the sCAN CAN shim driver with the devicetree, complete the following steps:

1. Specify the base address of the sCAN registers in RAM by creating the nordic,nrf-scan node within the RAM region reserved for the soft peripheral.

2. Specify an interrupt for communication between the application and FLPR cores, and determine the pins for sCAN operation. Provide this information in the properties of the node labeled as cpuflpr_vpr.

3. If the execution-memory property exists in the cpuflpr_vpr node, delete it to ensure the FLPR core does not use the Nordic VPR coprocessor launcher (see the CONFIG_NORDIC_VPR_LAUNCHER Kconfig option).

Testing

There are tests available in nrf/tests/zephyr/drivers/can/ which can be built and run. The CAN Shell can optionally be enabled to allow for locally testing the sCAN CAN shim driver. This is the simplest way to quickly send and receive some messages to validate its functionality.

There are also samples at zephyr/samples/drivers/can/ which can be built and run for any board defining the zephyr,canbus chosen node:

chosen {
        zephyr,canbus = &scan;
};

API documentation

Header file: zephyr/include/zephyr/drivers/can.h

Source file: nrf/drivers/can/can_nrf_scan.c

CAN