On Tue, Jul 28, 2015 at 9:39 AM, Lee Jones <lee.jones@xxxxxxxxxx> wrote:
> On Tue, 28 Jul 2015, Rob Herring wrote:
>
>> On Mon, Jul 27, 2015 at 10:20 AM, Lee Jones <lee.jones@xxxxxxxxxx> 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:
>> > + - opp-hz : CPU frequency [Hz] for this OPP [See: ./opp.txt]
>> > + - st,avs : List of available voltages [uV] indexed by process code
>>
>> Add a unit suffix (-microvolt).
>
> Sure.
>
>> > + - st,cuts : Cut version this OPP is suitable for [0xFF means ALL]
>> > + - st,substrate : Substrate version this OPP is suitable for [0xFF means ALL]
>>
>> How about not present means all?
>
> I think that would be an unsafe assumption. If it's forgotten, then
> we may try to run an invalid/dangerous voltage/frequency combination.
>
> I'd really like 'all' to be defined an deliberate.
Okay.
>> > +- 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
>>
>> Would the proposed nvmem binding work for this?
>
> We already use sysconf for all of this type of stuff, as this
> information is contained in ST's Sysconf banks. Moving over to a new
> API would be a huge move and would require lots of planning
> discussions with ST.
Okay.
Rob
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