Allwinner A40i / T3 Support for CAN

There is no CAN controller in the CPU of the A40i or T3, and CAN is used in the actual use process, usually using the SPI-to-CAN method.

On the OKA40i-C substrate, there is an SPI, but since the voltage does not match the voltage of mcp2515, this set of multiplexes of serial port 2 is used as the SPI external mcp2515 module.

According to chapter III of the CPU manual, the PI17-19 can be reused as SPI1, with PH08 as the interrupt.

The A40i/T3 features pin reuse in sys_config.fex or dts configuration, and we configure it with dts below.

01- Turn on SPI1

Modify the sys_config.fex, remove the configuration of uart2, and turn on the configuration of SPI1.

Also comment out PH08:

Modify the device tree at the same time:

02-Modify defconfig

Using a drive mcp251x .c verified by other platforms and adapted to the device tree,

Modify the defconfig profile:

Networking support ---> CAN bus subsystem support ---> CAN Device Drivers ---> Selected for Microchip MCP251x SPI CAN Controllers.

Also check the SPI configuration, which is supported by default and is no longer described here.

03-Configure iprote

file system:


Need to configure the BR2_PACKAGE_IPROUTE2 sy.

Recompile, package the image, burn.

04-Test can0 node

After starting, ifconfig looks at the can0 nodes that appear. Test with the following command:

ifconfig can0 down

ip link set can0 up type can bitrate 125000 triple-sampling on

ifconfig can0 up

cansend can0 123#12345678

candump can0

If necessary, contact Forlinx Technical Services to provide the patch file.


In the device tree, when used as an interrupt, because A40i/T3 can only use the pins of the PH group as an interrupt, the interrupt is set in the device tree as follows:

interrupt-parent = <&pio>;

interrupts =;

In addition, you need to pay attention to the interrupt trigger mode in the drive.