Re: [PATCH v5 1/4] dt-bindings: clock: google,gs101-clock: add samsung,sysreg property as required

Rob Herring (Arm)
2025-11-20T00:10:16Z

On Fri, 14 Nov 2025 14:16:48 +0000, Peter Griffin wrote:
> Each CMU (with the exception of cmu_top) has a corresponding sysreg bank
> that contains the BUSCOMPONENT_DRCG_EN and optional MEMCLK registers.
> The BUSCOMPONENT_DRCG_EN register enables dynamic root clock gating of
> bus components and MEMCLK gates the sram clock.
>
> Now the clock driver supports automatic clock mode, to fully enable dynamic
> root clock gating it is required to configure these registers. Update the
> bindings documentation so that all CMUs (with the exception of
> gs101-cmu-top) have samsung,sysreg as a required property.
>
> Note this is NOT an ABI break, as if the property isn't specified the
> clock driver will fallback to the current behaviour of not initializing
> the registers. The system still boots, but bus components won't benefit
> from dynamic root clock gating and dynamic power will be higher (which has
> been the case until now anyway).
>
> Additionally update the DT example to included the correct CMU size as
> registers in that region are used for automatic clock mode.
>
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> ---
> Changes in v5:
> - Invert the test for google,gs101-cmu-top (Andre)
>
> Changes in v4
> - Update commit description with additional requested details (Krzysztof)
>
> Changes in v3:
> - Update commit description as to why the sysreg is required (Krzysztof)
>
> Changes in v2:
> - Update commit description regarding updated example (Andre)
> ---
> .../devicetree/bindings/clock/google,gs101-clock.yaml | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>