Hi Krzysztof,

On 2022/11/09 0:11, Krzysztof Kozlowski wrote:

On 08/11/2022 15:30, Kunihiko Hayashi wrote:

quoted

Hi Krzysztof,

On 2022/11/08 20:13, Krzysztof Kozlowski wrote:

quoted

On 07/11/2022 11:34, Kunihiko Hayashi wrote:

quoted

Initial version of devicetree sources for NX1 SoC and boards.

NX1 SoC belongs to the UniPhier armv8 architecture platform, and is
designed for IoT and AI/ML application fields.

quoted

+
+		soc_glue: syscon@1f800000 {
+			compatible = "socionext,uniphier-nx1-soc-glue",
+				     "simple-mfd", "syscon";
+			reg = <0x1f800000 0x2000>;
+
+			pinctrl: pinctrl {
+				compatible = "socionext,uniphier-nx1-pinctrl";

So instead of documenting the hardware precisily, you have one big bag
for everything under simple-mfd. This is not how the SoC should be
described in DTS.

Sorry I don't understand. This is inherited from the previous
descriptions,
but is there some example to express DTS correctly about that?

I think yes, although it actually depends what is this hardware.
Generally speaking, do not use simple-mfd and syscon when these are not
really simple devices. There are quite many in your DTS, which got my
attention. Instead - have regular device with or without children.

There is no real need to have this a simple-mfd with one children
without any resources (no address space, no clocks, no interrupts, nothing).

Why this syscon/mfd and pinctrl is not a regular, one device?

The mfd/syscon.yaml says:
   System controller node represents a register region containing a set
   of miscellaneous registers.

The "soc-glue" is exactly this, it contains various register functions
and might be referred to the drivers.

For example in this NX1 dts, ethernet node points to "soc-glue" node.

     eth: ethernet@15000000 {
         compatible = "socionext,uniphier-nx1-ave4";
         ...
         socionext,syscon-phy-mode = <&soc_glue 0>;
     };

Since such register region is not often systematically designed,
it is tough to cut out as specific memory region for "pinctrl".

And more, the existing pinctrl driver uses of_get_parent() and
syscon_node_to_regmap(), so this change breaks compatibility.

quoted

quoted

quoted

+			};
+		};
+
+		soc-glue@1f900000 {
+			compatible = "simple-mfd";

No, it is not allowed on its own. You need a specific compatible and
bindings describing its children.

I saw the definition of "simple-mfd" itself is only in mfd/mfd.txt.

Currently there are only efuse devices as children, and this space means
nothing. I think it had better define the devices directly.

You need to start describe the hardware. efuse is an efuse, not MFD.
pinctrl is pinctrl not MFD + pinctrl.

This region also has multiple functions, though, the efuse might be
cut out as specific region without "simple-mfd", unlike pinctrl.

Thank you,

---
Best Regards
Kunihiko Hayashi

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