Subject: Re: [RFC PATCH v3 1/4] dt-bindings: net: can: add STM32 bxcan DT bindings

From: Rob Herring <[email-masked]>
Date: Wed, 31 Aug 2022 17:06:14 -0500

On Sun, Aug 28, 2022 at 03:33:26PM +0200, Dario Binacchi wrote:
> Add documentation of device tree bindings for the STM32 basic extended
> CAN (bxcan) controller.
> 
> Signed-off-by: Dario Binacchi <[email-masked]>
> 
> ---
> 
> Changes in v3:
> - Remove 'Dario Binacchi <[email-masked]>' SOB.
> - Add description to the parent of the two child nodes.
> - Move "patterProperties:" after "properties: in top level before "required".
> - Add "clocks" to the "required:" list of the child nodes.
> 
> Changes in v2:
> - Change the file name into 'st,stm32-bxcan-core.yaml'.
> - Rename compatibles:
>   - st,stm32-bxcan-core -> st,stm32f4-bxcan-core
>   - st,stm32-bxcan -> st,stm32f4-bxcan
> - Rename master property to st,can-master.
> - Remove the status property from the example.
> - Put the node child properties as required.
> 
>  .../bindings/net/can/st,stm32-bxcan.yaml      | 142 ++++++++++++++++++
>  1 file changed, 142 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
> 
> diff --git a/Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml b/Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
> new file mode 100644
> index 000000000000..3278c724e6f5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
> @@ -0,0 +1,142 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/net/can/st,stm32-bxcan.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: STMicroelectronics bxCAN controller
> +
> +description: STMicroelectronics BxCAN controller for CAN bus
> +
> +maintainers:
> +  - Dario Binacchi <[email-masked]>
> +
> +allOf:
> +  - $ref: can-controller.yaml#
> +
> +properties:
> +  compatible:
> +    description:
> +      It manages the access to the 512-bytes SRAM memory shared by the
> +      two bxCAN cells (CAN1 master and CAN2 slave) in dual CAN peripheral
> +      configuration.
> +    enum:
> +      - st,stm32f4-bxcan-core
> +
> +  reg:
> +    maxItems: 1
> +
> +  resets:
> +    maxItems: 1
> +
> +  clocks:
> +    description:
> +      Input clock for registers access
> +    maxItems: 1
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +patternProperties:
> +  "^can@[0-9]+$":
> +    type: object
> +    description:
> +      A CAN block node contains two subnodes, representing each one a CAN
> +      instance available on the machine.
> +
> +    properties:
> +      compatible:
> +        enum:
> +          - st,stm32f4-bxcan
> +
> +      st,can-master:
> +        description:
> +          Master and slave mode of the bxCAN peripheral is only relevant
> +          if the chip has two CAN peripherals. In that case they share
> +          some of the required logic, and that means you cannot use the
> +          slave CAN without the master CAN.
> +        type: boolean
> +
> +      reg:
> +        description: |
> +          Offset of CAN instance in CAN block. Valid values are:
> +            - 0x0:   CAN1
> +            - 0x400: CAN2
> +        maxItems: 1
> +
> +      interrupts:
> +        items:
> +          - description: transmit interrupt
> +          - description: FIFO 0 receive interrupt
> +          - description: FIFO 1 receive interrupt
> +          - description: status change error interrupt
> +
> +      interrupt-names:
> +        items:
> +          - const: tx
> +          - const: rx0
> +          - const: rx1
> +          - const: sce
> +
> +      resets:
> +        maxItems: 1
> +
> +      clocks:
> +        description:
> +          Input clock for registers access
> +        maxItems: 1
> +
> +    additionalProperties: false
> +
> +    required:
> +      - compatible
> +      - reg
> +      - interrupts
> +      - resets
> +      - clocks
> +
> +required:
> +  - compatible
> +  - reg
> +  - resets
> +  - clocks
> +  - '#address-cells'
> +  - '#size-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/stm32fx-clock.h>
> +    #include <dt-bindings/mfd/stm32f4-rcc.h>
> +
> +    can: can@40006400 {
> +        compatible = "st,stm32f4-bxcan-core";
> +        reg = <0x40006400 0x800>;
> +        resets = <&rcc STM32F4_APB1_RESET(CAN1)>;
> +        clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN1)>;
> +        #address-cells = <1>;
> +        #size-cells = <0>;

Again, the addressing is not correct here if 0 and 0x400 are memory 
mapped register offsets.

Rob

> +
> +        can1: can@0 {
> +            compatible = "st,stm32f4-bxcan";
> +            reg = <0x0>;
> +            interrupts = <19>, <20>, <21>, <22>;
> +            interrupt-names = "tx", "rx0", "rx1", "sce";
> +            resets = <&rcc STM32F4_APB1_RESET(CAN1)>;
> +            clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN1)>;
> +            st,can-master;
> +        };
> +
> +        can2: can@400 {
> +            compatible = "st,stm32f4-bxcan";
> +            reg = <0x400>;
> +            interrupts = <63>, <64>, <65>, <66>;
> +            interrupt-names = "tx", "rx0", "rx1", "sce";
> +            resets = <&rcc STM32F4_APB1_RESET(CAN2)>;
> +            clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN2)>;
> +        };
> +    };
> -- 
> 2.32.0
> 
>