Re: [PATCH v5 4/6] powercap: dtpm: Use generic powercap hierarchy helpers

[Heiko Stuebner <heiko@sntech.de>]

Am Dienstag, 3. November 2026, 05:48:18 Mitteleuropäische Normalzeit schrieb Daniel Lezcano:
> DTPM implements its own hierarchy creation and destruction logic while
> the powercap core now provides generic helpers for this purpose.
> 
> Convert DTPM to use the generic powercap hierarchy infrastructure.
> Duplicate the platform hierarchy before creating it, and use
> powercap_hierarchy_create() and powercap_hierarchy_destroy() to manage
> the DTPM zones.
> 
> Add DTPM callbacks to create and destroy the zones associated with each
> powercap hierarchy node. Adapt the CPU and devfreq backends to return
> the created DTPM instance and use the node name provided by the
> hierarchy.
> 
> Convert the Rockchip RK3399 description to struct powercap_hierarchy
> and keep the device tree path as DTPM-specific node data.
> 
> This removes the DTPM-specific hierarchy traversal and destruction code
> and leaves the hierarchy management to the powercap core.
> 
> Preserve best-effort creation: an unavailable backend returns NULL to
> skip its branch, and setup failures are warned about and skipped rather
> than rolling back independent zones. Invalid node descriptors remain
> fatal. Reject a DT node with a NULL path before calling
> of_find_node_by_path(), treating it as an invalid descriptor rather
> than an unavailable backend.
> 
> When the representative CPU is offline, find an active policy through an
> online sibling whose related_cpus mask contains it. Hold the CPU hotplug
> read lock during selection and setup, and initialize the zone through the
> policy's active CPU while keeping the hierarchy-provided name. An entirely
> offline policy still has no active CPU to initialize through.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>
> ---
> Changes in v5 (since v4):
> - Reject a NULL DT node path with -EINVAL before invoking
>   dtpm_setup_dt(), as suggested by Lukasz Luba.
> - Document that a missing path is an invalid hierarchy descriptor.
> 
> Changes in v4 (since v3):
> - Rebase on v7.3; no code or commit-description changes.
> 
> Changes in v3 (since v2):
> - Rebase on v7.3-rc7.
> - Preserve best-effort branch creation using the generic NULL result.
> - Find an online policy sibling for offline CPU representatives and
>   protect policy selection and setup against CPU hotplug.
> - Keep generic API behavior and documentation in patch 1.
> - Fix __initdata placement; match-table indentation is handled in patch 3.
> - Name setup callback arguments and remove whitespace-only lines.
> - Update the description.
> 
>  drivers/powercap/dtpm.c         | 180 +++++++++++++++-----------------
>  drivers/powercap/dtpm_cpu.c     |  62 ++++++++---
>  drivers/powercap/dtpm_devfreq.c |  22 ++--
>  drivers/soc/rockchip/dtpm.c     |  67 +++++++++---
>  include/linux/dtpm.h            |   6 +-
>  5 files changed, 198 insertions(+), 139 deletions(-)

I tried to follow along and the changes look ok, but I don't know the
more intricate details, so

Acked-by: Heiko Stuebner <heiko@sntech.de>