Re: [PATCH 01/12] dt-bindings: i3c: Add mipi-i3c-static-method to support SETAASA

[Conor Dooley <conor@kernel.org>]

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On Wed, Mar 18, 2026 at 10:57:14PM +0530, Akhil R wrote:
> Add the 'mipi-i3c-static-method' property mentioned in the MIPI I3C
> Discovery and Configuration Specification [1] to specify which discovery
> method an I3C device supports during bus initialization. The property is
> a bitmap, where a bit value of 1 indicates support for that method, and 0
> indicates lack of support.
> Bit 0: SETDASA CCC (Direct)
> Bit 1: SETAASA CCC (Broadcast)
> Bit 2: Other CCC (vendor / standards extension)
> All other bits are reserved.
> 
> It is specifically needed when an I3C device requires SETAASA for the
> address assignment. SETDASA will be supported by default if this property
> is absent - which means for now the property just serves as a flag to
> enable SETAASA, but keep the property as a bitmap to align with the
> specifications.
> 
> [1] https://www.mipi.org/specifications/disco
> 
> Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
> ---
>  .../devicetree/bindings/i3c/i3c.yaml          | 30 ++++++++++++++++---
>  1 file changed, 26 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/i3c/i3c.yaml b/Documentation/devicetree/bindings/i3c/i3c.yaml
> index e25fa72fd785..1705d90d4d79 100644
> --- a/Documentation/devicetree/bindings/i3c/i3c.yaml
> +++ b/Documentation/devicetree/bindings/i3c/i3c.yaml
> @@ -31,10 +31,12 @@ properties:
>        described in the device tree, which in turn means we have to describe
>        I3C devices.
>  
> -      Another use case for describing an I3C device in the device tree is when
> -      this I3C device has a static I2C address and we want to assign it a
> -      specific I3C dynamic address before the DAA takes place (so that other
> -      devices on the bus can't take this dynamic address).
> +      Other use-cases for describing an I3C device in the device tree are:
> +      - When the I3C device has a static I2C address and we want to assign
> +        it a specific I3C dynamic address before the DAA takes place (so
> +        that other devices on the bus can't take this dynamic address).
> +      - When the I3C device requires SETAASA for its discovery and uses a
> +        pre-defined static address.
>  
>    "#size-cells":
>      const: 0
> @@ -147,6 +149,26 @@ patternProperties:
>            through SETDASA. If static address is not present, this address is assigned
>            through SETNEWDA after assigning a temporary address via ENTDAA.
>  
> +      mipi-i3c-static-method:
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        minimum: 0x1
> +        maximum: 0xff
> +        default: 1
> +        description: |
> +          Bitmap describing which methods of Dynamic Address Assignment from a
> +          static address are supported by this I3C Target. A bit value of 1
> +          indicates support for that method, and 0 indicates lack of support.

I really am not keen on properties that are bitmaps, why can't we just
use the strings "setdasa", "setaasa" etc?

> +          Bit 0: SETDASA CCC (Direct)
> +          Bit 1: SETAASA CCC (Broadcast)
> +          Bit 2: Other CCC (vendor / standards extension)
> +          All other bits are reserved.
> +
> +          This property follows the MIPI I3C specification. The primary use
> +          of this property is to indicate support for SETAASA, i.e Bit 1, but
> +          will allow all values so that it is aligned with the specifications.
> +          SETDASA will remain as the default method even if this property is
> +          not present.
> +
>      required:
>        - reg
>  
> -- 
> 2.50.1
> 

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