Re: [PATCH v4 4/4] arm64: dts: allwinner: h616: Add BigTreeTech Pi support

["Jernej Škrabec" <jernej.skrabec@gmail.com>]

Dne sreda, 06. september 2023 ob 12:24:34 CEST je Andre Przywara napisal(a):
> On Tue, 05 Sep 2023 22:45:27 +0200
> Jernej Škrabec <jernej.skrabec@gmail.com> wrote:
> 
> Hi,
> 
> > 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 Škrabec
> > > > 
> > > > <jernej.skrabec@gmail.com> wrote:
> > > >> Dne nedelja, 13. avgust 2023 ob 18:22:49 CEST je Martin Botka
> > > >> 
> > > >> \x7fnapisal(a):
> > > >>>  On Sun, Aug 13 2023 at 05:55:35 PM +02:00:00, Jernej Škrabec
> > > >>>  
> > > >>>  <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
> > > >>> 
> > > >>> \x7f\x7fhappens 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) +=
> > > >>> 
> > > >>> \x7f\x7fsun50i-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
> > > >>> 
> > > >>> \x7f\x7fnew
> > > >>> 
> > > >>>  >> file
> > > >>>  >> 
> > > >>>  >>  mode 100644
> > > >>>  >>  index 000000000000..b0d0386e8f13
> > > >>>  >>  --- /dev/null
> > > >>>  >>  +++
> > > >>> 
> > > >>> \x7f\x7fb/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
> > > >>> 
> > > >>> \x7f\x7faccelerometer
> > > >>> 
> > > >>>  > */
> > > >>>  > 
> > > >>>  >>  +	status = "okay";
> > > >>>  >>  +	pinctrl-names = "default";
> > > >>>  >>  +	pinctrl-0 = <&spi0_pins>, <&spi0_cs0_pin>;
> > > >>>  > 
> > > >>>  > Driver and compatible for ADXL345 already exists, why don't you
> > > >>> 
> > > >>> \x7f\x7fadd
> > > >>> 
> > > >>>  > 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
> > > >> \x7fsoftware 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.
> 
> So I do understand the reasoning behind not describing those generic pin
> header connectors, where people could hook up anything, and use it as a
> GPIO or as a special function device, but just wanted to check on this
> situation:
> Don't we even describe pins dedicated to those custom connectors,
> especially if there is an "obvious" external device to connect to? Is it
> the same situation like with these FPC camera connectors?

I would say yes. SPI connector can still be used as GPIOs or anything else, 
since there is no device soldered directly to it.

Best regards,
Jernej

> 
> Cheers,
> Andre
> 
> > > >>>  The SPI connection is enabled so that klipper (3d printer
> > > >>> 
> > > >>> firmware) \x7f\x7fcan
> > > >>> 
> > > >>>  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
> > > >> \x7fyou'll use
> > > >> direct SPI commands from user space? AFAIK that's less and less
> > > >> \x7fsupported 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.
> > 
> > Can be CB1 bought separately from 3D printer package and thus used without
> > ADXL sensor?
> > 
> > > > 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.
> > 
> > Best regards,
> > Jernej
> > 
> > > Cheers,
> > > Martin
> > > 
> > > >> Best regards,
> > > >> Jernej
> > > >> 
> > > >>>  >>  +};
> > > >>>  >>  +
> > > >>>  >>  +&uart0 {
> > > >>>  >>  +	pinctrl-names = "default";
> > > >>>  >>  +	pinctrl-0 = <&uart0_ph_pins>;
> > > >>>  >>  +	status = "okay";
> > > >>>  >>  +};