On 09/11/2015 07:01 AM, Viresh Kumar wrote: > Regulators already have stable DT bindings, wherein the consumer (of > supplies) will have following for each regulator/supply. > > <name>-supply: <phandle to the regulator node>; > > Current OPP bindings extend above, by transforming it into a list of > phandles. But we missed the <name> string, which is used to identify the > regulator. > > And looking from regulators perspective, having two different ways of > specifying regulators doesn't seem like a step forward, it also means we > have to update every single device binding. And things will become > complex. > > Another way to support multiple regulators per device (in OPP V2 > bindings) is to leave regulator consumer bindings as is, and create a > 'supply-names' property in the opp-table node, which will contain a list > of strings. The names in this list shall match 'name' from the > '<name>-supply' strings present in the device node. > > The strings in this list also specify the order in which values must be > present in 'opp-microvolt' and 'opp-microamp' properties. > > Cc: Mark Brown <broo...@kernel.org> > Cc: devicet...@vger.kernel.org > Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org> > --- > Documentation/devicetree/bindings/opp/opp.txt | 26 +++++++++++++++++++------- > 1 file changed, 19 insertions(+), 7 deletions(-) > > diff --git a/Documentation/devicetree/bindings/opp/opp.txt > b/Documentation/devicetree/bindings/opp/opp.txt > index 0cb44dc21f97..8759bc4783ed 100644 > --- a/Documentation/devicetree/bindings/opp/opp.txt > +++ b/Documentation/devicetree/bindings/opp/opp.txt > @@ -69,6 +69,13 @@ This describes the OPPs belonging to a device. This node > can have following > - compatible: Allow OPPs to express their compatibility. It should be: > "operating-points-v2". > > +- supply-names: This is a required property, only if multiple supplies are > + available for the device. Otherwise it is optional. > + > + This list is used to pass names of all the device supplies. The order of > names > + present here is important, as that should match the order in which values > are > + present in 'opp-microvolt' and 'opp-microamp' properties. > +
What if we have a 2nd device and supply rail? For example, what if the L2$ has a separate rail from the cores but is linked to the OPPs. > - OPP nodes: One or more OPP nodes describing voltage-current-frequency > combinations. Their name isn't significant but their phandle can be used to > reference an OPP. > @@ -97,8 +104,8 @@ properties. > Single entry is for target voltage and three entries are for <target min > max> > voltages. > > - Entries for multiple regulators must be present in the same order as > - regulators are specified in device's DT node. > + Entries for multiple regulators must be present in the same order as their > + names are present in 'supply-names' property of the opp-table. > > - opp-microamp: The maximum current drawn by the device in microamperes > considering system specific parameters (such as transients, process, aging, > @@ -107,10 +114,12 @@ properties. > > Should only be set if opp-microvolt is set for the OPP. > > - Entries for multiple regulators must be present in the same order as > - regulators are specified in device's DT node. If this property isn't > required > - for few regulators, then this should be marked as zero for them. If it > isn't > - required for any regulator, then this property need not be present. > + Entries for multiple regulators must be present in the same order as their > + names are present in 'supply-names' property of the opp-table. > + > + If this property isn't required for few regulators, then this should be > marked > + as zero for them. If it isn't required for any regulator, then this > property > + need not be present. Remind me of when do we have multiple regulators for a cpu? The number of supplies should be defined by the cpu binding as function of how many supply rails a cpu has. > > - clock-latency-ns: Specifies the maximum possible transition latency (in > nanoseconds) for switching to this OPP from any other OPP. > @@ -369,13 +378,16 @@ Example 4: Handling multiple regulators > compatible = "arm,cortex-a7"; > ... > > - cpu-supply = <&cpu_supply0>, <&cpu_supply1>, > <&cpu_supply2>; > + vcc0-supply = <&cpu_supply0>; > + vcc1-supply = <&cpu_supply1>; > + vcc2-supply = <&cpu_supply2>; This may just be an example, but a CA7 doesn't have 3 supply rails. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
