RE: [PATCH v5 2/4] dt-bindings: aspeed: Add UART routing controller

[ChiaWei Wang <chiawei_wang@aspeedtech.com>]

Hi Rob,

> From: Rob Herring <robh@kernel.org>
> Sent: Friday, September 17, 2021 4:19 AM
> 
> On Thu, Sep 16, 2021 at 05:25:13PM +0800, Chia-Wei Wang wrote:
> > Add dt-bindings for Aspeed UART routing controller.
> >
> > Signed-off-by: Oskar Senft <osk@google.com>
> > Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
> > ---
> >  .../devicetree/bindings/mfd/aspeed-lpc.yaml   |  4 ++
> >  .../bindings/soc/aspeed/uart-routing.yaml     | 70
> +++++++++++++++++++
> >  2 files changed, 74 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/soc/aspeed/uart-routing.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml
> > b/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml
> > index 54f080df5e2f..697331d840a0 100644
> > --- a/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml
> > +++ b/Documentation/devicetree/bindings/mfd/aspeed-lpc.yaml
> > @@ -142,6 +142,10 @@ patternProperties:
> >        - interrupts
> >        - snoop-ports
> >
> > +  "^uart-routing@[0-9a-f]+$":
> > +    $ref: /schemas/soc/aspeed/uart-routing.yaml#
> > +    description: The UART routing control under LPC register space
> > +
> >  required:
> >    - compatible
> >    - reg
> > diff --git
> > a/Documentation/devicetree/bindings/soc/aspeed/uart-routing.yaml
> > b/Documentation/devicetree/bindings/soc/aspeed/uart-routing.yaml
> > new file mode 100644
> > index 000000000000..534b2a9340ce
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/soc/aspeed/uart-routing.yaml
> > @@ -0,0 +1,70 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) # #
> > +Copyright (c) 2018 Google LLC # # Copyright (c) 2021 Aspeed
> > +Technology Inc.
> > +%YAML 1.2
> > +---
> > +$id: "http://devicetree.org/schemas/soc/aspeed/uart-routing.yaml#"
> > +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> > +
> > +title: Aspeed UART Routing Controller
> > +
> > +maintainers:
> > +  - Oskar Senft <osk@google.com>
> > +  - Chia-Wei Wang <chiawei_wang@aspeedtech.com>
> > +
> > +description:
> > +  The Aspeed UART routing control allow to dynamically route the
> > +inputs for
> > +  the built-in UARTS and physical serial I/O ports.
> > +
> > +  This allows, for example, to connect the output of UART to another UART.
> > +  This can be used to enable Host <-> BMC communication via UARTs,
> > + e.g. to  allow access to the Host's serial console.
> > +
> > +  This driver is for the BMC side. The sysfs files allow the BMC
> > + userspace  which owns the system configuration policy, to configure
> > + how UARTs and  physical serial I/O ports are routed.
> > +
> > +  Two types of files, uart* and io*, are presented in sysfs. The
> > + uart*  configures the input signal of a UART controller whereas io*
> > + configures  that of a physical serial port.
> > +
> > +  When read, each file shows the list of available options with
> > + currently  selected option marked by brackets "[]". The list of
> > + available options  depends on the selected file.
> > +
> > +  e.g.
> > +  cat
> > + /sys/bus/platform/drivers/aspeed-uart-routing/*.uart_routing/uart1
> > +  [io1] io2 io3 io4 uart2 uart3 uart4 io6
> > +
> > +  In this case, UART1 gets its input from IO1 (physical serial port 1).
> 
> This is about documenting the hardware, not an OS driver.
> 
> sysfs files have their own documentation.
> 

Understood. I will remove this sysfs description from bindings in the next revision.
Thanks.

Chiawei