Re: [PATCH v1 02/29] dt-bindings: memory: tegra20: emc: Document new interconnect property

From: Thierry Reding
Date: Tue Nov 19 2019 - 01:22:05 EST


On Mon, Nov 18, 2019 at 11:02:20PM +0300, Dmitry Osipenko wrote:
> External memory controller is interconnected with memory controller and
> with external memory. Document new interconnect property which designates
> external memory controller as interconnect provider.
>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
> .../bindings/memory-controllers/nvidia,tegra20-emc.txt | 4 ++++
> 1 file changed, 4 insertions(+)

Do we really want to describe this particular connection? It's pretty
static and the only real connection here is the EMC frequency, so the
whole interconnect infrastructure seems a bit overkill.

Sounds to me like we could piggyback on top of the existing
nvidia,memory-controller property of the EMC to make the connection.

Thierry

>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> index add95367640b..7566d883f921 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt
> @@ -12,6 +12,9 @@ Properties:
> irrespective of ram-code configuration.
> - interrupts : Should contain EMC General interrupt.
> - clocks : Should contain EMC clock.
> +- #interconnect-cells : Should be 1. This cell represents external memory
> + interconnect. The assignments may be found in header file
> + <dt-bindings/interconnect/tegra-icc.h>.
>
> Child device nodes describe the memory settings for different configurations and clock rates.
>
> @@ -20,6 +23,7 @@ Example:
> memory-controller@7000f400 {
> #address-cells = < 1 >;
> #size-cells = < 0 >;
> + #interconnect-cells = < 1 >;
> compatible = "nvidia,tegra20-emc";
> reg = <0x7000f4000 0x200>;
> interrupts = <0 78 0x04>;
> --
> 2.23.0
>

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