STM32H7 Zephyr CAN Driver

[RIPHeisenberg]

Hello everyone,

I currently started with the STM32H747I_disco and CAN. The CAN implementation looks like this:

fdcan1: can@4000a000 {
compatible = "st,stm32h7-fdcan";
reg = <0x4000a000 0x400>, <0x4000ac00 0x350>;
reg-names = "m_can", "message_ram";
clocks = <&rcc STM32_CLOCK_BUS_APB1_2 0x00000100>;
interrupts = <19 0>, <21 0>, <63 0>;
interrupt-names = "LINE_0", "LINE_1", "CALIB";
bosch,mram-cfg = <0x0 28 8 3 3 0 3 3>;
sample-point = <875>;
sample-point-data = <875>;
status = "disabled";
};

I added following devicetree overlay file:

/ {
chosen {
zephyr,console = &arduino_serial;
zephyr,canbus = &fdcan1;
};

can_phy2: can-phy2 {
compatible = "can-transceiver-gpio";
enable-gpios = <&gpiob 8 GPIO_ACTIVE_LOW>;
standby-gpios = <&gpiob 9 GPIO_ACTIVE_HIGH>;
max-bitrate = <8000000>;
#phy-cells = <0>;
};
};

&fdcan1 {
compatible = "st,stm32h7-fdcan";
bus-speed = <125000>;
bus-speed-data = <1000000>;
status = "okay";
phys = <&can_phy2>;
};

void CAN_init(void) { can_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_canbus)); if (!device_is_ready(can_dev)) { printk("CAN: Device driver not ready.\n"); return 0; } }

The debug terminal sends a error message:

"can_stm32h7: CAN pinctrl setup failed (-2)"

I want to use the onboard CAN drivers but there isn't a native pinctrl configuration available in the YAML file. Some users have used different drivers like SPI to communicate with a external CAN driver this is not what I want. Am I getting something fundamentally wrong? Is it possible to use STM32 native CAN drivers with Zephyr. I could switch back to the STM32 hal drivers, but I'd rather not.

Informations:
STM32H747i_DISCOVERY
Zephyr 3.5.99
Zephyr SDK 0.16.5
commit: 023d483

I'm compiling and running the project on the M4 chip.

I hope this information is sufficient to get ahead. Its my first post and I'd really like to get in touch with the community.

Best regards

[henrikbrixandersen]

"can_stm32h7: CAN pinctrl setup failed (-2)"

Everything in your DTS snippets above look fine, except that you're missing a pinctrl configuration in &fdcan1 { ... } (and you shouldn't override compatible there). Try something like the following, replacing the pinctrl pins with the actual pins routed to your CAN transceiver:

&fdcan1 {
        pinctrl-0 = <&fdcan1_rx_pb8 &fdcan1_tx_ph13>;
        pinctrl-names = "default";
        bus-speed = <125000>;
        bus-speed-data = <1000000>;
        status = "okay";
        phys = <&can_phy2>;
};

Current main (and the upcoming Zephyr v3.6.0) furthermore supports specifying the domain clock for FDCAN, a feature you may or may not need depending on your board clock configuration. See commit bc69500 for further details.

Am I getting something fundamentally wrong? Is it possible to use STM32 native CAN drivers with Zephyr. I could switch back to the STM32 hal drivers, but I'd rather not.

It is definitely possible, yes. I am using the FDCAN driver for the STM32H7 myself.

[erwango]

Likely your hal_stm32 module is outdated.
File mentioned by @henrikbrixandersen is available in recent version of the repo, which you see by running a west update command.

[RIPHeisenberg]

Hey thanks for the hint. I added hal_stm32 to my west.yml file. I wasn't aware that this was mandatory. Now I'm getting the devicetree definitions. Very nice :D

the code however still doesn't compile...

My devicetree looks like this now:

fdcan1: can@4000a000 {
compatible = "st,stm32h7-fdcan";
reg = <0x4000a000 0x400>, <0x4000ac00 0x350>;
reg-names = "m_can", "message_ram";
clocks = <&rcc STM32_CLOCK_BUS_APB1_2 0x00000100>;
interrupts = <19 0>, <21 0>, <63 0>;
interrupt-names = "LINE_0", "LINE_1", "CALIB";
bosch,mram-cfg = <0x0 28 8 3 3 0 3 3>;
sample-point = <875>;
sample-point-data = <875>;
status = "okay";
pinctrl-0 = <&fdcan1_rx_pb8 &fdcan1_tx_pb9>;
bus-speed = <125000>;
bus-speed-data = <1000000>;
};

Is there something wrong with it?
Err:
In: /west_workspace/zephyr/drivers/can/can_stm32h7_fdcan.c

error: 'PINCTRL_STATE_DT_N_S_soc_S_can_4000a000_PINCTRL_IDX_0_UPPER_TOKEN' undeclared here (not in a function); did you mean 'DT_N_S_soc_S_spi_40015000_PINCTRL_IDX_0_UPPER_TOKEN'?
91 | CONCAT(PINCTRL_STATE,
| ^~~~~~~~~~~~~~

Do I have to add additional kconfig configurations?

[erwango]

At least, you're missing following property: pinctrl-names = "default";.
But I'm surprised this error is not caught earlier actually.

[RIPHeisenberg]

That actually was the issue. Thanks! It finally compiles now. And it seems as if packages are being send. :D I'll have to test it with a can module but I think this should work out.

1. Adding stm32_hal to zephyr west.yml file

Final overlay file:

#include <st/h7/stm32h747Xi_m4.dtsi>

/ {
chosen {
zephyr,console = &uart8;
zephyr,canbus = &fdcan1;
};
};

&uart8 {
status="okay";
};

&fdcan1 {
pinctrl-names = "default";
pinctrl-0 = <&fdcan1_rx_pb8 &fdcan1_tx_pb9>;
bus-speed = <125000>;
bus-speed-data = <1000000>;
status = "okay";
};

Kconfig:

CONFIG_GPIO=y
CONFIG_CAN=y
CONFIG_CAN_FD_MODE=y
CONFIG_CAN_STM32H7_FDCAN=y

CONFIG_ISOTP=y
CONFIG_REBOOT=y

CONFIG_LOG=y
CONFIG_DEBUG=y
CONFIG_CONSOLE=y
CONFIG_PRINTK=y
CONFIG_UART_CONSOLE=y
CONFIG_LOG_BACKEND_UART=y

CONFIG_SAMPLE_RX_THREAD_STACK_SIZE=1024
CONFIG_SAMPLE_RX_THREAD_PRIORITY=7

We have two receiving contexts that are bound to a single address.

CONFIG_ISOTP_RX_SF_FF_BUF_COUNT=2

It might help someone else in the future. Thanks for the support <3

Cheers