Re: [PATCH v2 3/6] ARM: dts: sun8i: s3: Add dtsi for the Elimo Impetus SoM

[Matteo Scordino]

-- 
Matteo Scordino / Embedded Software Consultant
Mobile: +44 (0)7463701446

On Mon, 2020-11-02 at 11:05 +0100, Maxime Ripard wrote:
> Hi!
> 
> On Fri, Oct 30, 2020 at 11:43:22PM +0000, Matteo Scordino wrote:
> > The Elimo Engineering Impetus is an Open Source Hardware System-on-Module
> > based on the SoChip S3 SoC.
> > 
> > It is meant for integration into carrier boards or, more generally,
> > larger designs, and uses an M2 connector to facilitate that.
> > 
> > Interfaces on the M.2/NGFF 42mm connector:
> > WiFi IEEE 802. 11abgn (on-module Realtek)
> > Bluetooth 4.2/BLE (on-module Realtek)
> > RGB LCD Interface (on-module connector)
> > MIPI Camera Interface (on-module connector)
> > IEEE 802. 3u Ethernet MAC (external connecto)
> > USB2.0 (Host, Device, OTG) (external connector)
> > Audio Line In/Out (external connector)
> > 
> > Signed-off-by: Matteo Scordino <matteo.scordino@xxxxxxxxx>
> > ---
> >  arch/arm/boot/dts/sun8i-s3-elimo-impetus.dtsi | 51 +++++++++++++++++++
> >  1 file changed, 51 insertions(+)
> >  create mode 100644 arch/arm/boot/dts/sun8i-s3-elimo-impetus.dtsi
> > 
> > diff --git a/arch/arm/boot/dts/sun8i-s3-elimo-impetus.dtsi b/arch/arm/boot/dts/sun8i-s3-elimo-impetus.dtsi
> > new file mode 100644
> > index 000000000000..f219188fc9ba
> > --- /dev/null
> > +++ b/arch/arm/boot/dts/sun8i-s3-elimo-impetus.dtsi
> > @@ -0,0 +1,51 @@
> > +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> > +/*
> > + * Copyright (C) 2020 Matteo Scordino <matteo@xxxxxxxx>
> > + */
> > +
> > +/dts-v1/;
> > +#include "sun8i-v3.dtsi"
> > +#include "sunxi-common-regulators.dtsi"
> > +
> > +/ {
> > +	model = "Elimo Impetus SoM";
> > +	compatible = "elimo,impetus", "sochip,s3", "allwinner,sun8i-v3";
> > +
> > +	aliases {
> > +		serial0 = &uart0;
> > +		serial1 = &uart1;
> > +	};
> > +
> > +	chosen {
> > +		stdout-path = "serial0:115200n8";
> > +	};
> > +};
> > +
> > +&mmc0 {
> > +	broken-cd;
> > +	bus-width = <4>;
> > +	vmmc-supply = <&reg_vcc3v3>;
> > +	status = "okay";
> > +};
> > +
> > +&uart0 {
> > +	pinctrl-0 = <&uart0_pb_pins>;
> > +	pinctrl-names = "default";
> > +	status = "okay";
> > +};
> > +
> > +&uart1 {
> > +	pinctrl-0 = <&uart1_pg_pins>;
> > +	pinctrl-names = "default";
> > +	status = "okay";
> > +};
> 
> What is uart1 used for? the BT chip?
> 
> Maxime

No, BT is provided over SDIO by a Cypress 43455.
When used with the Initium carrier board, UART1 goes to an FTDI bridge that is
connected to the same USB-C connector that is used for power.
The idea being, if want an application that uses the UART to communicate with a
PC, it's convenient to provide power+connectivity on a single port.

I guess your point is that we would be better off only defining this in the DTS
of the carrier board?

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