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Date:   Tue, 05 Sep 2023 22:49:02 +0200
From:   Martin Botka <martin.botka@somainline.org>
Subject: Re: [PATCH v4 4/4] arm64: dts: allwinner: h616: Add BigTreeTech Pi
 support
To:     Jernej =?iso-8859-2?q?=A9krabec?= <jernej.skrabec@gmail.com>
Cc:     Martin Botka <martin.botka1@gmail.com>,
        Martin Botka <martin@biqu3d.com>,
        Konrad Dybcio <konrad.dybcio@somainline.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@somainline.org>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Jami Kettunen <jamipkettunen@somainline.org>,
        Paul Bouchara <paul.bouchara@somainline.org>,
        Andre Przywara <andre.przywara@arm.com>,
        Martin Botka <martin@biqu3d.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Chen-Yu Tsai <wens@csie.org>,
        Samuel Holland <samuel@sholland.org>,
        Ludwig Kormann <ludwig.kormann@ict42.de>,
        Andrew Lunn <andrew@lunn.ch>, Icenowy Zheng <uwu@icenowy.me>,
        Heiko Stuebner <heiko@sntech.de>,
        Shawn Guo <shawnguo@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Chris Morgan <macromorgan@hotmail.com>,
        Jagan Teki <jagan@edgeble.ai>,
        Maxime Ripard <mripard@kernel.org>, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
        linux-kernel@vger.kernel.org
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        <1909632.taCxCBeP46@archlinux>
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On Tue, Sep 5 2023 at 10:45:27 PM +02:00:00, Jernej ?krabec 
<jernej.skrabec@gmail.com> wrote:
> On Thursday, August 24, 2023 10:48:20 PM CEST Martin Botka wrote:
>>  On Mon, Aug 14 2023 at 12:47:59 PM +02:00:00, Martin Botka
>> 
>>  <martin.botka@somainline.org> wrote:
>>  > On Mon, Aug 14 2023 at 12:26:07 PM +02:00:00, Jernej ?krabec
>>  >
>>  > <jernej.skrabec@gmail.com> wrote:
>>  >> Dne nedelja, 13. avgust 2023 ob 18:22:49 CEST je Martin Botka
>>  >>
>>  >> napisal(a):
>>  >>>  On Sun, Aug 13 2023 at 05:55:35 PM +02:00:00, Jernej ?krabec
>>  >>>
>>  >>>  <jernej.skrabec@gmail.com> wrote:
>>  >>>  > Dne ponedeljek, 07. avgust 2023 ob 16:53:24 CEST je Martin 
>> Botka
>>  >>>  >
>>  >>>  > napisal(a):
>>  >>>  >>  The BigTreeTech Pi is an H616 based board based on CB1.
>>  >>>  >>  Just in Rpi format board.
>>  >>>  >>
>>  >>>  >>  It features the same internals as BTT CB1 but adds:
>>  >>>  >>      - Fan port
>>  >>>  >>      - IR receiver
>>  >>>  >>      - ADXL345 Accelerometer connector via SPI
>>  >>>  >>      - 24V DC power supply via terminal plugs
>>  >>>  >>      - USB to CAN module connector (The actual USB to CAN
>>  >>>
>>  >>> happens on
>>  >>>
>>  >>>  >> the
>>  >>>  >>
>>  >>>  >>  external module)
>>  >>>  >>
>>  >>>  >>  List of currently working things is same as BTT CB1 but 
>> also:
>>  >>>  >>      - IR receiver
>>  >>>  >>      - ADXL345 connector
>>  >>>  >>
>>  >>>  >>  Signed-off-by: Martin Botka <martin@biqu3d.com>
>>  >>>  >>  Reviewed-by: Andre Przywara <andre.przywara@arm.com>
>>  >>>  >>  ---
>>  >>>  >>
>>  >>>  >>  Changes in V2:
>>  >>>  >>      - Add UART alongside aliases and chosen for it
>>  >>>  >>      - Add model string
>>  >>>  >>      - Enable IR receiver
>>  >>>  >>      - Enable SPI0 for ADXL345 connector
>>  >>>  >>
>>  >>>  >>  Changes in V3:
>>  >>>  >>      - Add missing semicolons
>>  >>>  >>      - Add pinctrl for SPI0
>>  >>>  >>
>>  >>>  >>   arch/arm64/boot/dts/allwinner/Makefile        |  1 +
>>  >>>  >>   .../allwinner/sun50i-h616-bigtreetech-pi.dts  | 70
>>  >>>  >>
>>  >>>  >> +++++++++++++++++++
>>  >>>  >>
>>  >>>  >>   2 files changed, 71 insertions(+)
>>  >>>  >>   create mode 100644
>>  >>>  >>
>>  >>>  >>  
>> arch/arm64/boot/dts/allwinner/sun50i-h616-bigtreetech-pi.dts
>>  >>>  >>
>>  >>>  >>  diff --git a/arch/arm64/boot/dts/allwinner/Makefile
>>  >>>  >>  b/arch/arm64/boot/dts/allwinner/Makefile index
>>  >>>  >>
>>  >>>  >> 7b386428510b..0b6232a7f328
>>  >>>  >>
>>  >>>  >>  100644
>>  >>>  >>  --- a/arch/arm64/boot/dts/allwinner/Makefile
>>  >>>  >>  +++ b/arch/arm64/boot/dts/allwinner/Makefile
>>  >>>  >>  @@ -39,5 +39,6 @@ dtb-$(CONFIG_ARCH_SUNXI) +=
>>  >>>  >>
>>  >>>  >> sun50i-h6-pine-h64-model-b.dtb
>>  >>>  >>
>>  >>>  >>  dtb-$(CONFIG_ARCH_SUNXI) += sun50i-h6-tanix-tx6.dtb
>>  >>>  >>
>>  >>>  >>   dtb-$(CONFIG_ARCH_SUNXI) += sun50i-h6-tanix-tx6-mini.dtb
>>  >>>  >>   dtb-$(CONFIG_ARCH_SUNXI) +=
>>  >>>
>>  >>> sun50i-h616-bigtreetech-cb1-manta.dtb
>>  >>>
>>  >>>  >>  +dtb-$(CONFIG_ARCH_SUNXI) += sun50i-h616-bigtreetech-pi.dtb
>>  >>>  >>
>>  >>>  >>   dtb-$(CONFIG_ARCH_SUNXI) += sun50i-h616-orangepi-zero2.dtb
>>  >>>  >>   dtb-$(CONFIG_ARCH_SUNXI) += sun50i-h616-x96-mate.dtb
>>  >>>  >>
>>  >>>  >>  diff --git
>>  >>>  >>
>>  >>>  >> 
>> a/arch/arm64/boot/dts/allwinner/sun50i-h616-bigtreetech-pi.dts
>>  >>>  >>
>>  >>>  >>  
>> b/arch/arm64/boot/dts/allwinner/sun50i-h616-bigtreetech-pi.dts
>>  >>>
>>  >>> new
>>  >>>
>>  >>>  >> file
>>  >>>  >>
>>  >>>  >>  mode 100644
>>  >>>  >>  index 000000000000..b0d0386e8f13
>>  >>>  >>  --- /dev/null
>>  >>>  >>  +++
>>  >>>
>>  >>> b/arch/arm64/boot/dts/allwinner/sun50i-h616-bigtreetech-pi.dts
>>  >>>
>>  >>>  >>  @@ -0,0 +1,70 @@
>>  >>>  >>  +// SPDX-License-Identifier: (GPL-2.0+ or MIT)
>>  >>>  >>  +/*
>>  >>>  >>  + * Copyright (C) 2023 Martin Botka <martin@biqu3d.com>.
>>  >>>  >>  + */
>>  >>>  >>  +
>>  >>>  >>  +/dts-v1/;
>>  >>>  >>  +
>>  >>>  >>  +#include "sun50i-h616-bigtreetech-cb1.dtsi"
>>  >>>  >>  +
>>  >>>  >>  +/ {
>>  >>>  >>  +	model = "BigTreeTech Pi";
>>  >>>  >>  +	compatible = "bigtreetech,pi", "allwinner,sun50i-h616";
>>  >>>  >>  +
>>  >>>  >>  +	aliases {
>>  >>>  >>  +		serial0 = &uart0;
>>  >>>  >>  +	};
>>  >>>  >>  +
>>  >>>  >>  +	chosen {
>>  >>>  >>  +		stdout-path = "serial0:115200n8";
>>  >>>  >>  +	};
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ehci0 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ehci1 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ehci2 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ehci3 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ir {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ohci0 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ohci1 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ohci2 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&ohci3 {
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&spi0 {
>>  >>>  >>  +	/* SPI connection for onboard connector for ADXL345
>>  >>>
>>  >>> accelerometer
>>  >>>
>>  >>>  > */
>>  >>>  >
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +	pinctrl-names = "default";
>>  >>>  >>  +	pinctrl-0 = <&spi0_pins>, <&spi0_cs0_pin>;
>>  >>>  >
>>  >>>  > Driver and compatible for ADXL345 already exists, why don't 
>> you
>>  >>>
>>  >>> add
>>  >>>
>>  >>>  > child node
>>  >>>  > for it?
>>  >>>  >
>>  >>>  > Best regards,
>>  >>>  > Jernej
>>  >>>
>>  >>>  Ah. So the ADXL345 actually wont be driven by kernel.
>>  >>
>>  >> DT is hardware description, it's not concerned what is done on
>>  >> software side,
>>  >> either kernel or user space.
>>  >
>>  > Im aware. But this is not a device that is on the board. Its 
>> simply a
>>  > connector for the device.
>>  > Like Rpi has connectors for camera module :)
> 
> Actually it matters only if this other board is firmly connected with 
> base
> board. If it is not, then SPI node should be dropped and be handled 
> with DT
> overlays.
Got it. Will drop it then.
> 
>>  >
>>  >>>  The SPI connection is enabled so that klipper (3d printer
>>  >>>
>>  >>> firmware) can
>>  >>>
>>  >>>  be told to look for ADXL345 at this SPI and use it on its own.
>>  >>>
>>  >>>  Klipper will initialize and communicate with the ADXL on its 
>> own.
>>  >>
>>  >> What do you mean by firmware? User space app? In this case I 
>> suppose
>>  >> you'll use
>>  >> direct SPI commands from user space? AFAIK that's less and less
>>  >> supported by
>>  >> kernel (in contrast to I2C).
>>  >
>>  > Firmware as in 3d printer firmware. Klipper runs on the board 
>> (CB1 or
>>  > BTT Pi) and is indeed an userspace app.
>>  > And indeed uses direct SPI commands to the device.
>>  >
>>  > The reason for this is the flexibility.
>>  > If Klipper read the values from kernel or well from the files the
>>  > ADXL driver would create
>>  > then it would be unable to communicate with ADXL that is on 
>> toolhead
>>  > board. Or would have to have
>>  > direct initialization either way for those. Thus it just controls 
>> the
>>  > ADXL itself :)
>>  >
>>  > I understand that this may be bit confusing. If there is still
>>  > something not clear im more then happy to explain in
>>  > full detail how the userspace and 3D printer communicate :)
> 
> As I said, DT doesn't care about implementation. DT is HW 
> description, so
> either if it's fixed connection (soldered wires), then describe in 
> full,
> otherwise it's considered addon board and thus non-essential, so it 
> should be
> handled with DT overlays.
OK
> 
> Can be CB1 bought separately from 3D printer package and thus used 
> without
> ADXL sensor?
Yes
> 
>>  >
>>  > Cheers,
>>  > Martin.
>> 
>>  Hello,
>>  Jernej any comments on this ?
>>  I would like to resolve this conversation :)
>>  We do have a bunch of time before the new cycle but never hurts to 
>> get
>>  it figured out ahead of time :)
> 
> Sorry, not enough free time over summer.
No worries :)

Cheers,
Martin
> 
> Best regards,
> Jernej
> 
>> 
>>  Cheers,
>>  Martin
>> 
>>  >> Best regards,
>>  >> Jernej
>>  >>
>>  >>>  >>  +};
>>  >>>  >>  +
>>  >>>  >>  +&uart0 {
>>  >>>  >>  +	pinctrl-names = "default";
>>  >>>  >>  +	pinctrl-0 = <&uart0_ph_pins>;
>>  >>>  >>  +	status = "okay";
>>  >>>  >>  +};
> 
> 
> 
>