Re: [PATCH 0/2] Add CDSP Power Manangement Driver

[Vignesh Viswanathan]

On 5/20/2026 4:14 PM, Krzysztof Kozlowski wrote:
> On Wed, May 20, 2026 at 12:35:08AM +0530, Vignesh Viswanathan wrote:
>> On platforms like IPQ9650, the CDSP subsystem cannot manage its own power
>> rails and requires the APSS to handle power management on its behalf. Add a
>> platform driver to fulfill this role.
>>
>> Handle LPM (Low Power Mode) by executing hardware isolation and restoration
>> sequences via MPM register programming, coordinated with the NSP Q6 through
>> a handshake protocol. Support both FULL_PC (CX+MX collapse) and LONG_APCR
>> (CX-only) modes, detected dynamically at runtime.
>>
>> Handle DCVS (Dynamic Clock and Voltage Scaling) requests from the NSP Q6
>> received via a shared SMEM channel. Apply voltages via the regulator
>> framework and write responses back to SMEM.
>>
>> Expose virtual cdsp-vdd-cx and cdsp-vdd-mx regulators so that the PAS
>> remoteproc driver can control the NSP power rails through the standard
>> regulator framework.
>>
>> This driver functionally depends on [1] for bringing up the CDSP on
>> IPQ9650, but there is no compile time dependency.
>>
>> [1] https://lore.kernel.org/linux-arm-msm/20260519-mp8899-regulator-driver-v1-0-30d14421b7f1@xxxxxxxxxxxxxxxx/T/#t
>>
>> ---
>> Praveenkumar I (1):
>>       soc: qcom: Add CDSP power management driver
> 
> Power management drivers CANNOT go to drivers/soc.

Ack.

> 
>>
>> Vignesh Viswanathan (1):
>>       dt-bindings: soc: qcom: Document CDSP Power Management
> 
> Neither to bindings soc.

Ack, As per Bjorn's review, this CDSP power management driver + standard PAS
driver will be a non-standard implementation and I'm looking at moving this
into a new remoteproc driver. Will address in next version.

Thanks,
Vignesh

> 
> Best regards,
> Krzysztof
>