Re: [RFC PATCH] ARM: dts: Add support for Turris Omnia

From: Andrew Lunn
Date: Tue Nov 22 2016 - 19:35:50 EST


> +++ b/arch/arm/boot/dts/armada-385-turris-omnia.dts
> @@ -0,0 +1,279 @@
> +/*
> + * Device Tree file for the Turris Omnia
> + * Schematic available at https://www.turris.cz/doc/_media/rtrom01-schema.pdf

Hi Tomas

Cool that there is a link to the schematics. But please could you put
it lower down. It is more likely to be seen if it comes after the
copyright and license section.

> + sdhci@d8000 {
> + pinctrl-names = "default";
> + pinctrl-0 = <&sdhci_pins>;
> + status = "okay";
> +
> + bus-width = <8>;
> + no-1-8-v;
> + non-removable;
> + };

> +&i2c0 {
> + pinctrl-names = "default";
> + pinctrl-0 = <&i2c0_pins>;
> + status = "okay";
> +
> + i2cmux@70 {
> + compatible = "nxp,pca9547";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <0x70>;
> + status = "okay";
> +
> + /* Channel 1: Routed to PCIe0/mSATA connector (CN7A).
> + * Channel 2: Routed to PCIe1/USB2 connector (CN61A).
> + * Channel 3: Routed to PCIe2 connector (CN62A).
> + * Channel 4: Routed to SFP+.
> + * Channel 5: ATSHA204A at address 0x64.
> + * Channel 6: Routed to user pin header CN11.
> + */

I've not looked at how the pca9547 works.... Will it instantiate a bus
only if there is a node in the device tree with a reg property?

What i'm thinking is that it is possible to indicate to the i2c core
that a device is on a bus using echo to a file. But this only works if
the bus exists. You could for example say using echo that there is an
at24 EEPROM on channel 4 and get access to the EEPROM inside the SFP
module. But that only works if the i2c bus exists. Does it?

No leds? No buttons via gpio-keys?

Andrew