Re: [PATCH RFC] Add cpufreq support

[Viresh Kumar <viresh.kumar@linaro.org>]

On 08-02-16, 14:10, Arnd Bergmann wrote:
> I don't remember the exact discussion, but the compatible string is
> exactly meant to do one thing: it tells you what you can or cannot do
> with one device.

Yeah, and many people argued that we can't add two values to that
string like: "cpufreq-dt" and "cpufreq-big-little" for same kind of
OPP bindings, as a different compatible string should be required only
if there is a difference in the bindings.

For example, if a platform (like ST did recently) adds more
platform-specific properties, then they can define a new value of
those strings.

> I had not realized that we don't even have a compatible string
> for opp-v2, so if we are missing that, we obviously can't compare
> against that string.

The binding says that we can have a string, but its not compulsory
yet. Its only used by STM as they have some specific properties of
their own.

> I thought there was a compatible property in there that told us
> whether the operating-points-v2/cooling-min-level/#cooling-cells/...
> properties were considered valid.

Yeah, "OPP-v2" DT node can have a compatible string, which isn't
compulsory as of now, but because of the reasons mentioned earlier, we
can't use it to differentiate between drivers that use exactly same
version of bindings.

-- 
viresh