Re: [RFC PATCH v2 1/4] dt-bindings: net: can: add STM32 bxcan DT bindings

[Dario Binacchi <dario.binacchi@amarulasolutions.com>]

Hi Rob,

On Thu, Aug 25, 2022 at 11:12 PM Rob Herring <robh@kernel.org> wrote:
>
> On Sat, Aug 20, 2022 at 10:29:33AM +0200, Dario Binacchi wrote:
> > Add documentation of device tree bindings for the STM32 basic extended
> > CAN (bxcan) controller.
> >
> > Signed-off-by: Dario Binacchi <dariobin@libero.it>
> > Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> >
> > ---
> >
> > 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      | 136 ++++++++++++++++++
> >  1 file changed, 136 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..288631b5556d
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
> > @@ -0,0 +1,136 @@
> > +# 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 <dario.binacchi@amarulasolutions.com>
> > +
> > +allOf:
> > +  - $ref: can-controller.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - st,stm32f4-bxcan-core
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  resets:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    description:
> > +      Input clock for registers access
> > +    maxItems: 1
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 0
> > +
> > +additionalProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - resets
> > +  - clocks
> > +  - '#address-cells'
> > +  - '#size-cells'
> > +
> > +patternProperties:
> > +  "^can@[0-9]+$":
> > +    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
> > +
> > +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>;
> > +
>
> Missing 'ranges'.

In the file arch/arm/boot/dts/stm32f429.dtsi, I didn't find any other
node using the 'ranges' property, so
I didn't use it for the CAN node either.

>
> > +        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)>;
> > +            st,can-master;
>
> No clocks?

It uses the parent node clock, since it is in master mode.

Thanks and regards,
Dario

>
> > +        };
> > +
> > +        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
> >
> >



-- 

Dario Binacchi

Embedded Linux Developer

dario.binacchi@amarulasolutions.com

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