On 30.07.2020 14:28, Sylwester Nawrocki wrote:
> On 09.07.2020 23:04, Rob Herring wrote:
>> On Thu, Jul 02, 2020 at 06:37:19PM +0200, Sylwester Nawrocki wrote:
>>> Add documentation for new optional properties in the exynos bus nodes:
>>> samsung,interconnect-parent, #interconnect-cells, bus-width.
>>> These properties allow to specify the SoC interconnect structure which
>>> then allows the interconnect consumer devices to request specific
>>> bandwidth requirements.
>>>
>>> Signed-off-by: Artur Świgoń <a.swigon@xxxxxxxxxxx>
>>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
>>> --- a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
>>> +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
>>> @@ -51,6 +51,13 @@ Optional properties only for parent bus device:
>>> - exynos,saturation-ratio: the percentage value which is used to calibrate
>>> the performance count against total cycle count.
>>>
>>> +Optional properties for interconnect functionality (QoS frequency constraints):
>>> +- samsung,interconnect-parent: phandle to the parent interconnect node; for
>>> + passive devices should point to same node as the exynos,parent-bus property.
>> Adding vendor specific properties for a common binding defeats the
>> point.
Actually we could do without any new property if we used existing interconnect
consumers binding to specify linking between the provider nodes. I think those
exynos-bus nodes could well be considered both the interconnect providers
and consumers. The example would then be something along the lines
(yes, I know the bus node naming needs to be fixed):
soc {
bus_dmc: bus_dmc {
compatible = "samsung,exynos-bus";
/* ... */
samsung,data-clock-ratio = <4>;
#interconnect-cells = <0>;
};
bus_leftbus: bus_leftbus {
compatible = "samsung,exynos-bus";
/* ... */
interconnects = <&bus_leftbus &bus_dmc>;
#interconnect-cells = <0>;
};
bus_display: bus_display {
compatible = "samsung,exynos-bus";
/* ... */
interconnects = <&bus_display &bus_leftbus>;
#interconnect-cells = <0>;
};
&mixer {
compatible = "samsung,exynos4212-mixer";
interconnects = <&bus_display &bus_dmc>;
/* ... */
};
};
What do you think, Georgi, Rob?
--
Regards
Sylwester
