Pin assignments SPIS nrf52

[lachlansmith]

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I'd like to use SPIS on the Particle Argon but I can't figure out the csn-pin to use. I believe boards > arm > particle_argon > dts > mesh_feather_spi_spi1.dtsi references the nrf52 pin assignments. This leads me to believe I need to look at nordic, however I'm struggling to see the relation between the dtsi file and nordic's documentation.

Could someone who knows something help with understanding the mapping of gpio1 15 -> 47, gpio1 14 -> 46, gpio1 13 -> 45 and my problem which is gpio0 31 -> ?, and how they got there?

&spi1 {
	compatible = "nordic,nrf-spis";
	status = "okay";
	sck-pin = <47>;
	mosi-pin = <45>;
	miso-pin = <46>;
        // cs-gpios = < &gpio0 31 GPIO_ACTIVE_LOW>;
	csn-pin = <?>;
	def-char = <0x00>;

	bt-hci@0 {
		compatible = "zephyr,bt-hci-spi-slave";
		reg = <0>;
		irq-gpios = <&gpio0 2 (GPIO_ACTIVE_HIGH | GPIO_PULL_DOWN)>;
	};
};

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Documentation/mesh_feather_spis_spi1.dtsi example

[lachlansmith]

I'm unsure if this is correct but it seems like a pretty good guess. Since a GPIO bus goes from [0 ... 31] and gpio1 is the "next" bus the mapping is gpio1 14 = 31 + 14 + 1 (indexing 0) = 46. So the pins are referencing the GPIO number plus whatever bus they are on. Hate when things seem obvious after the fact. I can't find documentation on this so I assume this is just a known convention I haven't come across before.

Thus, gpio0 31 = 31 ?