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

[Akhil R]

On Thu, 26 Mar 2026 16:44:31 +0100, Alexandre Belloni wrote:
> On 26/03/2026 10:05:03-0500, Rob Herring wrote:
>> On Wed, Mar 18, 2026 at 05:31:50PM +0000, Conor Dooley wrote:
>> > 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@xxxxxxxxxx>
>> > > ---
>> > >  .../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?
>> 
>> If this comes from a specification, then I'd tend to just copy it rather 
>> than invent our own thing. Obviously if is something structured 
>> fundamentally different from how DT is designed, then we wouldn't. But 
>> this is just a simple property.
>> 
> 
> The issue being that the specification is not public so it is difficult
> to take any decision.

There is a public version available in the same link, but you would still
have to provide them a name and an email ID. The document will be sent to
the mail ID.

Regards,
Akhil