Re: [PATCH 2/2] PM / devfreq: qcom: Introduce CCI devfreq driver

[Jun Nie <jun.nie@linaro.org>]

Dmitry Baryshkov <dmitry.baryshkov@linaro.org> 于2023年2月1日周三 19:32写道：
>
> On 01/02/2023 10:02, Jun Nie wrote:
> > Cache Coherent Interconnect (CCI) is used by some Qualcomm SoCs. This
> > driver is introduced so that its freqency can be adjusted. And regulator
> > associated with opp table can be also adjusted accordingly which is
> > shared with cpu cluster.
> >
> > Signed-off-by: Jun Nie <jun.nie@linaro.org>
> > ---
> >   drivers/devfreq/Kconfig    |   9 +++
> >   drivers/devfreq/Makefile   |   1 +
> >   drivers/devfreq/qcom-cci.c | 162 +++++++++++++++++++++++++++++++++++++
> >   3 files changed, 172 insertions(+)
> >   create mode 100644 drivers/devfreq/qcom-cci.c
>
> Could you please describe in some additional details what are you trying
> to achieve? Should the CCI frequency be scaled manually or does it
> follow the cluster frequency? Do clusters vote on the CCI frequency?
>
> I'm inclined to ask if it is possible to shift this to the cpufreq OPP
> tables?
>
> --
> With best wishes
> Dmitry
>

The plan is to add CCI opp node as required-opp property in CPU opp, so that
CPU will vote CCI frequency when scaling CPU frequency.
The interconnect bandwidth side is not addressed yet. This patch only address
CCI frequency and power voltage requirement with help of device tree.

- Jun