Re: [PATCH V1 Resend 2/3] cpufreq: dt: Add generic platform-device creation support

From: Viresh Kumar
Date: Fri Apr 01 2016 - 08:52:24 EST


On 01-04-16, 14:30, Mason wrote:
> Hmmm... I'm using the older operating-points prop in my platform's DT.
> Why can't we define a new property (e.g. "enable-generic-cpufreq")
> which registers the "cpufreq-dt" pseudo-device?

DT is all about expressing hardware in a file. The same bindings
should be usable across any operating system, not just Linux. And so
we shouldn't have any OS or software-implementation specific
properties here.

> And platforms that manually register "cpufreq-dt" would be
> automatically white-listed, even if they don't have the new
> property, to maintain backward-compat?

Its not about just making it work, otherwise we would have done it
long time back by creating a DT node for cpufreq-dt driver.

> > @Rob: Will that be acceptable to you? We are discussing (again) about how to
> > probe cpufreq-dt driver automatically for platforms :)
> >
> > The cpus node doesn't have any 'compatible' property today, and I will be
> > required to add that in this case.
>
> Why does it need a compatible prop?

That compatible property will describe how to parse/describe
operating-points for a CPU. Any driver, which has the ability to parse
those bindings can do things base on such a compatibility string.

I hope you got the idea.

--
viresh