linux-kernel - Re: [PATCH v2 1/2] dt-bindings: arm,scmi: Do not use clocks for SCMI performance domains

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Date:   Fri, 23 Oct 2020 08:24:06 -0500
From:   Rob Herring <robh+dt@...nel.org>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        devicetree@...r.kernel.org,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
Subject: Re: [PATCH v2 1/2] dt-bindings: arm,scmi: Do not use clocks for SCMI
 performance domains

On Thu, Oct 22, 2020 at 1:22 PM Sudeep Holla <sudeep.holla@....com> wrote:
>
> On Wed, Oct 21, 2020 at 07:31:03PM +0100, Sudeep Holla wrote:
> > Commit dd461cd9183f ("opp: Allow dev_pm_opp_get_opp_table() to return
> > -EPROBE_DEFER") handles -EPROBE_DEFER for the clock/interconnects within
> > _allocate_opp_table() which is called from dev_pm_opp_add and it
> > now propagates the error back to the caller.
> >
> > SCMI performance domain re-used clock bindings to keep it simple. However
> > with the above mentioned change, if clock property is present in a device
> > node, opps can't be added until clk_get succeeds. So in order to fix the
> > issue, we can register dummy clocks which is completely ugly.
> >
> > Since there are no upstream users for the SCMI performance domain clock
> > bindings, let us introduce separate performance domain bindings for the
> > same.
> >
> > Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> > ---
> >  .../devicetree/bindings/arm/arm,scmi.txt      | 19 ++++++++++++++++---
> >  1 file changed, 16 insertions(+), 3 deletions(-)
> >
> > v1[1]->v2:
> >       - Changed the generic #perf-domain-cells to more SCMI specific
> >         property #arm,scmi-perf-domain-cells
> >
>
> Is more specific #arm,scmi-perf-domain-cells acceptable ?
> Sorry for the rush, but this fixes SCMI cpufreq which is broken after
> commit dd461cd9183f ("opp: Allow dev_pm_opp_get_opp_table() to return
> -EPROBE_DEFER")

If you are in a rush, you'd better go the dummy clock route. We should
get this binding right and I think that means something common, not
SCMI specific.

Rob