Device tree binding for DVFS table
Mike Turquette
mturquette at ti.com
Wed Jul 11 16:04:02 EDT 2012
On 20120711-15:44, Mark Brown wrote:
> On Wed, Jul 11, 2012 at 09:03:41AM -0500, Rob Herring wrote:
>
> > I'd expect a single property with freq/volt pairs or 2 properties for
> > freq and voltage where there is a 1:1 relationship (freq N uses voltage N).
>
> I strongly agree - the current proposal is very hard to read due to the
> separation between the voltage and frequency values. Some devices do
> also need to scale multiple rails together, especially when this gets
> used for I/O devices.
>
> I'd also expect to see a range of voltages for each frequency rather
> than a specific voltage; usually things are at least characterised with
> a specified tolerance.
Not only should we support multiple voltage rails but also multiple
clocks. For some devices a DVFS transition is composed of scaling
multiple clock rates together. So some sort of clock identifier
(phandle?) is needed as well. (forgive my ignorance on the phandle
part, as I am a DT noob)
Regards,
Mike
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