Re: [RFC 14/14] dt-bindings: tegra: Add Tegra210 EMC binding

[Rob Herring <robh@kernel.org>]

On Fri, Sep 14, 2018 at 11:03:09PM +0300, Peter De Schrijver wrote:
> Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>

Needs a commit msg.

> ---
>  .../memory-controllers/nvidia,tegra210-emc.txt     | 448 +++++++++++++++++++++
>  1 file changed, 448 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt
> 
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt
> new file mode 100644
> index 0000000..1c52f47
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt
> @@ -0,0 +1,448 @@
> +NVIDIA Tegra210 SoC EMC (external memory controller)
> +====================================================
> +
> +Required properties :
> +- compatible : Should be "nvidia,tegra21-emc", "nvidia,tegra124-emc".
> +- reg : physical base address and length of the controller's registers.
> +- nvidia,memory-controller : phandle of the MC driver.

Huh? What is this block then?

> +- clocks : phandles of the possible source clocks
> +- clock-names : names of the possible source clocks
> +
> +The node should contain a "emc-table" subnode for each supported RAM type
> +(see field RAM_CODE in register PMC_STRAPPING_OPT_A), with its unit address
> +being its RAM_CODE.

Unit address is based on reg property.

> +
> +Required properties for "emc-table" nodes :
> +- nvidia,ram-code : Should contain the value of RAM_CODE this timing set is
> +used for.
> +
> +Each "emc-table" node should contain a "emc-table" subnode for every supported
> +EMC clock rate. The "emc-table" subnodes should have the clock rate in kHz as
> +their unit address.
> +
> +Required properties for "emc-table" nodes :

Which emc-table nodes, the child or grand-child nodes?

> +- compatible  "nvidia,tegra21-emc-table", "nvidia,tegra210-emc-table"

> +- nvidia,revision : revision of the parameter set used for this node. All
> +                    nodes in the same "emc-table" should have the same revision
> +- clock-frequency : frequency in kHz
> +- nvidia,emc-min-mv : minimum voltage for this OPP
> +- nvidia,gk20a-min-mv : minimum GPU voltage for this OPP
> +- nvidia,source : clock source to be used for this OPP

Is this memory timings/settings or OPPs? We have a binding for OPPs 
already.

> +- nvidia,src-sel-reg : value of EMC CAR register to be used for this OPP
> +- nvidia,needs-training : 1 if the OPP needs training at boot, 0 otherwise
> +- nvidia,trained : 1 if initial training has been done by firmware, 0 otherwise
> +- nvidia,periodic_training : 1 if the OPP needs periodic training, 0 otherwise
> +- nvidia,trained_dram_clktree_c0d0u0 : training data word
> +- nvidia,trained_dram_clktree_c0d0u1 : training data word

[...]

This is a huge list of properties. For all the things that are memory 
timings, is there really value to defining a property for each setting? 
Perhaps you should just define your own format and either make it a 
separate firmware file or include that file in the dtb.

Rob