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From: Rob Herring <robh+dt@kernel.org>
Date: Wed, 3 Jan 2024 13:22:43 -0700
Message-ID: <CAL_Jsq+yPHT3VRVzNh1NY03KUoKvN41zzQKtqYvxxGjvv754Zw@mail.gmail.com>
Subject: Re: [PATCH] dt-bindings: serial: Describe ARM dcc interface
To: Michal Simek <michal.simek@amd.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, linux-kernel@vger.kernel.org, 
	monstr@monstr.eu, michal.simek@xilinx.com, git@xilinx.com, 
	Conor Dooley <conor+dt@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
	Jiri Slaby <jirislaby@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, devicetree@vger.kernel.org, 
	linux-serial@vger.kernel.org
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On Tue, Jan 2, 2024 at 8:32=E2=80=AFAM Michal Simek <michal.simek@amd.com> =
wrote:
>
>
>
> On 12/22/23 09:20, Krzysztof Kozlowski wrote:
> > On 21/12/2023 15:05, Michal Simek wrote:
> >> Debug Communication Channel (DCC) provides the way how to pass data be=
tween
> >> target CPU and host via JTAG interface. Every CPU has own interface fo=
r
> >> communication via dbgdtrtx_el0 and dbgdtrrx_el0 registers.
> >>
> >> Signed-off-by: Michal Simek <michal.simek@amd.com>
> >> ---
> >>
> >> This communication interface is used for flash programming on Xilinx
> >> SOCs from U-Boot.
> >> https://source.denx.de/u-boot/u-boot/-/blob/master/drivers/serial/arm_=
dcc.c
> >>
> >> ---
> >>   .../devicetree/bindings/serial/arm,dcc.yaml   | 30 +++++++++++++++++=
++
> >>   1 file changed, 30 insertions(+)
> >>   create mode 100644 Documentation/devicetree/bindings/serial/arm,dcc.=
yaml
> >>
> >> diff --git a/Documentation/devicetree/bindings/serial/arm,dcc.yaml b/D=
ocumentation/devicetree/bindings/serial/arm,dcc.yaml
> >> new file mode 100644
> >> index 000000000000..fd0589356617
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/serial/arm,dcc.yaml
> >> @@ -0,0 +1,30 @@
> >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> +%YAML 1.2
> >> +---
> >> +$id: http://devicetree.org/schemas/serial/arm,dcc.yaml#
> >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> +
> >> +title: ARM DCC (Data communication channel) serial emulation
> >> +
> >> +maintainers:
> >> +  - Michal Simek <michal.simek@amd.com>
> >> +
> >> +description: |
> >> +  ARM DCC (Data communication channel) serial emulation interface ava=
ilable
> >> +  via JTAG can be also used as one of serial line tightly coupled wit=
h every
> >> +  ARM CPU available in the system.
> >> +
> >> +properties:
> >> +  compatible:
> >> +    const: arm,dcc
> >> +
> >> +required:
> >> +  - compatible
> >
> > no allOf: with $ref to serial.yaml? Does it differ somehow?
>
> Valid one could be only nodename format and maybe label.
> Others are not relevant. But if that's fine I can also add it.

Yeah, I think serial.yaml mostly doesn't apply here. Not really worth
including for just the node name.

Greg may have already processed this, so you might want to resend. Or
wait a few days and I'll just apply it.

Rob