Re: [PATCH 2/3] soundwire: qcom: add multi-master support

[Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>]

On 9/14/26 6:21 PM, Pierre-Louis Bossart wrote:
> On 9/11/26 10:21, Srinivas Kandagatla wrote:
>> v3.1.0+ Qualcomm SoundWire IPs can be paired to expose one logical
>> bus with more than two DATA lanes. One IP owns SWR_CLK and drives
>> the bus; the other contributes DATA lanes only.
>>
>> Support this pairing on the driver side. A device link between the
>> two IPs enforces correct unbind ordering and keeps the peer resumed
>> while the primary is active.
>>
>> Single-master deployments (no qcom,multi-master-mode in DT) are
>> unaffected.
> 
> It'd be good to clarify how the command protocol is handled. Each IP is
> probably capable of handling PING/READ/WRITE commands in Column0, but in
> the paired option the primary IP is the only one that deals with Column0
> and all other DATA lanes are just data?
All the control/command is only handled by Primary controller, dependent
controllers only contribute to additional data lines.

only Primary handles slave register reads/writes.

I will clarify this in next version.

thanks,
Srini
>