On Tue, 28 Jul 2015, Stephen Boyd wrote: > On 07/28, Viresh Kumar wrote: > > Cc'ing few people (whom I cc'd last time as well :)). > > > > On 27-07-15, 16:20, Lee Jones wrote: > > > These OPPs are used in ST's CPUFreq implementation. > > > > > > Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> > > > --- > > > > > > Changelog: > > > - None, new patch > > > > > > Documentation/devicetree/bindings/power/opp-st.txt | 76 ++++++++++++++++++++++ > > > 1 file changed, 76 insertions(+) > > > create mode 100644 Documentation/devicetree/bindings/power/opp-st.txt > > > > > > diff --git a/Documentation/devicetree/bindings/power/opp-st.txt b/Documentation/devicetree/bindings/power/opp-st.txt > > > new file mode 100644 > > > index 0000000..6eb2a91 > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/power/opp-st.txt > > > @@ -0,0 +1,76 @@ > > > +STMicroelectronics OPP (Operating Performance Points) Bindings > > > +-------------------------------------------------------------- > > > + > > > +Frequency Scaling only > > > +---------------------- > > > + > > > +Located in CPU's node: > > > + > > > +- operating-points : [See: ./opp.txt] > > > + > > > +Example [safe] > > > +-------------- > > > + > > > +cpus { > > > + cpu@0 { > > > + /* kHz uV */ > > > + operating-points = <1500000 0 > > > + 1200000 0 > > > + 800000 0 > > > + 500000 0>; > > > + }; > > > +}; > > > + > > > +Dynamic Voltage and Frequency Scaling (DVFS) > > > +-------------------------------------------- > > > + > > > +Located in 'cpu0-opp-list' node [to be provided ONLY by the bootloader]: > > > + > > > +- compatible : Should be "operating-points-v2-sti" > > > +- opp{1..N} : Each 'oppX' subnode will contain the following properties: > > > > Or should we mention: > > - opp{1..N} : Each 'oppX' subnode shall contain below properties, > > over what ./opp.txt defines: > > > > ? > > > > > > > + - opp-hz : CPU frequency [Hz] for this OPP [See: ./opp.txt] > > > + - st,avs : List of available voltages [uV] indexed by process code > > > + - st,cuts : Cut version this OPP is suitable for [0xFF means ALL] > > > + - st,substrate : Substrate version this OPP is suitable for [0xFF means ALL] > > > +- st,syscfg : Phandle to Major number register > > > + First cell: offset to major number > > > +- st,syscfg-eng : Phandle to Minor number and Pcode registers > > > + First cell: offset to process code > > > + Second cell: offset to minor number > > > + > > > +WARNING: The opp{1..N} nodes will be provided by the bootloader. Do not attempt to > > > + artificially synthesise the opp{1..N} nodes or any of their descendants. > > > + They are very platform specific and may damage the hardware if created > > > + incorrectly. > > > + > > > +Example [unsafe] > > > +---------------- > > > + > > > +cpus { > > > + cpu@0 { > > > + operating-points-v2 = <&cpu0_opp_list>; > > > + }; > > > +}; > > > + > > > +/* ############################################################ */ > > > +/* # WARNING: Do not attempt to copy/replicate this node, # */ > > > +/* # it is only to be supplied by the bootloader !!! # */ > > > +/* ############################################################ */ > > > +cpu0-opp-list { > > > + compatible = "operating-points-v2-sti"; > > > + st,syscfg = <&syscfg [major_offset]>; > > > + st,syscfg-eng = <&syscfg_eng [pcode_offset] [minor_offset]>; > > > + > > > + opp0 { > > > + opp-hz = <1200000000>; > > > + st,avs = <1110 1150 1100 1080 1040 1020 980 930>; > > > + st,substrate = <0xff>; > > > + st,cuts = <0xff>; > > > + }; > > > + opp1 { > > > + opp-hz = <1500000000>; > > > + st,avs = <1200 1200 1200 1200 1170 1140 1100 1070>; > > > + st,substrate = <0xff>; > > > + st,cuts = <0x2>; > > > + }; > > > +}; > > > > I don't see more problems here, unless we can move some of this to the > > generic bindings. > > > > @Rob/Stephen: Please respond before it is late :) > > It's interesting to have vendor specific properties like avs, > cuts, and substrate. That could replace our planned usage of the > opp-names property where we encode similar information (speed > bin, revision, etc.) into a string that we look for. > > So I wonder why the avs/cut/substrate information can't be > encoded into the opp name? That would make these properties > obsolete, given that all they're used for is to pick out the > correct OPP? You could hack the substrate and cut version into a string, but that's exactly what it would be, a hack. I'm struggling how you would do the same for 'st,avs', which is an array of u32s. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- 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