Re: [PATCH RFT v1 1/3] drm/panfrost: enable devfreq based the "operating-points-v2" property

[Robin Murphy]

[ +Sudeep ]

On 08/01/2020 12:38 pm, Martin Blumenstingl wrote:
> Hi Robin,
>
> On Wed, Jan 8, 2020 at 12:18 PM Robin Murphy <robin.murphy@xxxxxxx> wrote:
> > On 07/01/2020 11:06 pm, Martin Blumenstingl wrote:
> > > Decouple the check to see whether we want to enable devfreq for the GPU
> > > from dev_pm_opp_set_regulators(). This is preparation work for adding
> > > back support for regulator control (which means we need to call
> > > dev_pm_opp_set_regulators() before dev_pm_opp_of_add_table(), which
> > > means having a check for "is devfreq enabled" that is not tied to
> > > dev_pm_opp_of_add_table() makes things easier).
> >
> > Hmm, what about cases like the SCMI DVFS protocol where the OPPs are
> > dynamically discovered rather than statically defined in DT?
> where can I find such an example (Amlogic SoCs use SCPI instead of
> SCMI, so I don't think that I have any board with SCMI support) or
> some documentation?
> (I could only find SCPI clock and CPU DVFS implementations, but no
> generic "OPPs for any device" implementation)

On closer inspection I think this applies to the SCPI DVFS protocol 
too[1]. AIUI the fact that neither is wired up to a devfreq driver yet 
is merely due to lack of demand and suitable systems to develop/test on 
so far - the panfrost devfreq code is only now looking like the first 
viable upstream use-case ;)

Robin.

[1] http://infocenter.arm.com/help/topic/com.arm.doc.dui0922g/BABFEBCD.html