On 03-05-17, 12:29, Sudeep Holla wrote: > > > On 28/04/17 21:48, Rob Herring wrote: > > On Wed, Apr 26, 2017 at 04:27:05PM +0530, Viresh Kumar wrote: > >> Power-domains need to express their active states in DT and the devices > >> within the power-domain need to express their dependency on those active > >> states. The power-domains can use the OPP tables without any > >> modifications to the bindings. > >> > >> Add a new property "power-domain-opp", which will contain phandle to the > >> OPP node of the parent power domain. This is required for devices which > >> have dependency on the configured active state of the power domain for > >> their working. > >> > >> For some platforms the actual frequency and voltages of the power > >> domains are managed by the firmware and are so hidden from the high > >> level operating system. The "opp-hz" property is relaxed a bit to > >> contain indexes instead of actual frequency values to support such > >> platforms. > >> > >> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx> > >> --- > >> Documentation/devicetree/bindings/opp/opp.txt | 74 ++++++++++++++++++++++++++- > >> 1 file changed, 73 insertions(+), 1 deletion(-) > >> > >> diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt > >> index 63725498bd20..6e30cae2a936 100644 > >> --- a/Documentation/devicetree/bindings/opp/opp.txt > >> +++ b/Documentation/devicetree/bindings/opp/opp.txt > >> @@ -77,7 +77,10 @@ This defines voltage-current-frequency combinations along with other related > >> properties. > >> > >> Required properties: > >> -- opp-hz: Frequency in Hz, expressed as a 64-bit big-endian integer. > >> +- opp-hz: Frequency in Hz, expressed as a 64-bit big-endian integer. In some > >> + cases the exact frequency in Hz may be hidden from the OS by the firmware and > >> + this field may contain values that represent the frequency in a firmware > >> + dependent way, for example an index of an array in the firmware. > > > > Not really sure OPP binding makes sense here. What about all the other > > properties. We expose voltage, but not freq? > > > > I completely agree with that and I have been pushing this to be > represented as just regulators[0]. Mark B seem to dislike that > idea [1] Just as an update, Rajendra confirmed (offline) that for some of the implementations, the microcontroller handles both frequency and voltages of a device. So it isn't just a regulator anymore and as me and Kevin were saying, we need a complete OPP here. -- viresh -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
