Re: [EXT] Re: [PATCH 1/2 v4] dt-bindings: dspi: added for semtech sx1301

[Michael Walle]

Am 2022-04-21 16:23, schrieb Rob Herring:

> What's needed here is a connector node (and driver) for the mikrobus
> socket. The connector node's purpose is to decouple the host DT from
> add-on board overlay DT. Something like this:

Funny I had a similar idea to have a connector with all the
properties, but I failed to see how that would be of any help.

Do you mind an example of such an overlay? Judging by the spi
and i2c subnode, I guess it will amend the connector node and
fill in it's devices?

And all the child device properties will reference the connector,
correct?

> connector {
> 	// And a more specific compatible if pins can have alt funcs?
> 	// Spec version needed?
> 	compatible = "mikrobus-socket";
>
> 	// Will need regulators defined if child devices expect
> 	// regulators
> 	vcc-33-supply = <&reg33>;
> 	vcc-5-supply = <&reg5v>;
>
> 	i2c-parent = <&i2c1>; // Already a defined property
> 	spi-parent = <&spi0>; // New

uart/serial needed too?

> 	// RST pin
> 	reset-gpios = <&gpio 4 0>;
>
> 	// remap 'INT' (index 0) to host interrupt
> 	#interrupt-cells = <2>;
> 	#address-cells = <0>;
> 	interrupt-map = <0 0 &gpio 3 0>;
>
> 	spi {

For example:

my-device@0 {
  reg = <0>;  // really needed? there is only one SPI CS line
  compatible = "my-device";
  reset-gpios = // may be left unset if it's optional, but what
                // what if it is a required property and in hardware
                // its connected to the RST pin of the module?
  other-gpios = <&connector 2>;
  vdd-supply = // what comes here? <&connector VCC_33>?
  interrupts-extended = <&connector 0 ..>;
}

-michael

> 		//devices
> 	};
>
> 	i2c {
>
> 	};
> };
>
> The DT spec defines 'foo-map' properties extending interrupt-map.
> Currently only GPIO is defined. We might want to do the same thing for
> PWM. Or we make the connector node both a PWM consumer and provider.
>
> Rob