From: Georgi Djakov <georgi.djakov@linaro.org>
To: Sylwester Nawrocki <s.nawrocki@samsung.com>,
Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
b.zolnierkie@samsung.com, linux-pm@vger.kernel.org,
sw0312.kim@samsung.com, a.swigon@samsung.com, krzk@kernel.org,
linux-kernel@vger.kernel.org, inki.dae@samsung.com,
cw00.choi@samsung.com, myungjoo.ham@samsung.com,
dri-devel@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com
Subject: Re: [PATCH RFC v6 1/6] dt-bindings: exynos-bus: Add documentation for interconnect properties
Date: Wed, 9 Sep 2020 12:07:46 +0300 [thread overview]
Message-ID: <b711257d-c34b-b609-3ada-312871967b98@linaro.org> (raw)
In-Reply-To: <35d9d396-b553-a815-1f3b-1af4dc37a2ca@samsung.com>
Hi Sylwester,
On 8/28/20 17:49, Sylwester Nawrocki wrote:
> 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@samsung.com>
>>>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>
>>>> --- 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>;
Hmm, bus_display being a consumer of itself is a bit odd? Did you mean:
interconnects = <&bus_dmc &bus_leftbus>;
> #interconnect-cells = <0>;
> };
>
>
> &mixer {
> compatible = "samsung,exynos4212-mixer";
> interconnects = <&bus_display &bus_dmc>;
> /* ... */
> };
> };
>
> What do you think, Georgi, Rob?
I can't understand the above example with bus_display being it's own consumer.
This seems strange to me. Could you please clarify it?
Otherwise the interconnect consumer DT bindings are already well established
and i don't see anything preventing a node to be both consumer and provider.
So this should be okay in general.
Thanks,
Georgi
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next prev parent reply other threads:[~2020-09-09 9:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200702163746eucas1p2363251b3b6fb6084123cedd67fa132d5@eucas1p2.samsung.com>
2020-07-02 16:37 ` [PATCH RFC v6 0/6] Exynos: Simple QoS for exynos-bus using interconnect Sylwester Nawrocki
[not found] ` <CGME20200702163748eucas1p2cf7eab70bc072dea9a95183018b38ad3@eucas1p2.samsung.com>
2020-07-02 16:37 ` [PATCH RFC v6 1/6] dt-bindings: exynos-bus: Add documentation for interconnect properties Sylwester Nawrocki
2020-07-03 0:47 ` Chanwoo Choi
2020-07-09 21:04 ` Rob Herring
2020-07-30 12:28 ` Sylwester Nawrocki
2020-08-28 14:49 ` Sylwester Nawrocki
2020-09-09 9:07 ` Georgi Djakov [this message]
2020-09-09 14:47 ` Sylwester Nawrocki
2020-09-15 21:40 ` Georgi Djakov
2020-10-30 12:29 ` Sylwester Nawrocki
[not found] ` <CGME20200702163753eucas1p16fbd5d59d05fb8e4fdcde9df839cb71e@eucas1p1.samsung.com>
2020-07-02 16:37 ` [PATCH RFC v6 2/6] interconnect: Add generic interconnect driver for Exynos SoCs Sylwester Nawrocki
[not found] ` <CGME20200702163754eucas1p2bbe44897234a3e39dcd10b23e536a927@eucas1p2.samsung.com>
2020-07-02 16:37 ` [PATCH RFC v6 3/6] PM / devfreq: exynos-bus: Add registration of interconnect child device Sylwester Nawrocki
[not found] ` <CGME20200702163756eucas1p282c6bc5a61f8dd7b6a5d59d92e92e2f1@eucas1p2.samsung.com>
2020-07-02 16:37 ` [PATCH RFC v6 4/6] ARM: dts: exynos: Add interconnect properties to Exynos4412 bus nodes Sylwester Nawrocki
[not found] ` <CGME20200702163758eucas1p1e18d95f3dce34df1f4334da5462a04a2@eucas1p1.samsung.com>
2020-07-02 16:37 ` [PATCH RFC v6 5/6] ARM: dts: exynos: Add interconnects to Exynos4412 mixer Sylwester Nawrocki
[not found] ` <CGME20200702163801eucas1p12db276c7ac9e244e93e4b2f3d33ba729@eucas1p1.samsung.com>
2020-07-02 16:37 ` [PATCH RFC v6 6/6] drm: exynos: mixer: Add interconnect support Sylwester Nawrocki
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