Date:   Tue, 28 Jul 2020 09:27:07 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Michael Walle <michael@...le.cc>
Cc:     linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org,
        linux-pwm@...r.kernel.org, linux-watchdog@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Shawn Guo <shawnguo@...nel.org>, Li Yang <leoyang.li@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <maz@...nel.org>, Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Pavel Machek <pavel@....cz>,
        Rob Herring <robh@...nel.org>
Subject: Re: [PATCH v6 02/13] dt-bindings: mfd: Add bindings for sl28cpld

On Tue, 28 Jul 2020, Michael Walle wrote:

> Am 2020-07-28 09:24, schrieb Lee Jones:
> > On Sun, 26 Jul 2020, Michael Walle wrote:
> > 
> > > Add a device tree bindings for the board management controller found
> > > on
> > > the Kontron SMARC-sAL28 board.
> > > 
> > > Signed-off-by: Michael Walle <michael@...le.cc>
> > > Reviewed-by: Rob Herring <robh@...nel.org>
> > > ---
> > > Changes since v5:
> > >  - none
> > > 
> > > Changes since v4:
> > >  - fix the regex of the unit-address
> > > 
> > > Changes since v3:
> > >  - see cover letter
> > > 
> > >  .../bindings/gpio/kontron,sl28cpld-gpio.yaml  |  54 +++++++
> > >  .../hwmon/kontron,sl28cpld-hwmon.yaml         |  27 ++++
> > >  .../kontron,sl28cpld-intc.yaml                |  54 +++++++
> > >  .../bindings/mfd/kontron,sl28cpld.yaml        | 153
> > > ++++++++++++++++++
> > >  .../bindings/pwm/kontron,sl28cpld-pwm.yaml    |  35 ++++
> > >  .../watchdog/kontron,sl28cpld-wdt.yaml        |  35 ++++
> > >  6 files changed, 358 insertions(+)
> > >  create mode 100644
> > > Documentation/devicetree/bindings/gpio/kontron,sl28cpld-gpio.yaml
> > >  create mode 100644
> > > Documentation/devicetree/bindings/hwmon/kontron,sl28cpld-hwmon.yaml
> > >  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/kontron,sl28cpld-intc.yaml
> > >  create mode 100644
> > > Documentation/devicetree/bindings/mfd/kontron,sl28cpld.yaml
> > >  create mode 100644
> > > Documentation/devicetree/bindings/pwm/kontron,sl28cpld-pwm.yaml
> > >  create mode 100644
> > > Documentation/devicetree/bindings/watchdog/kontron,sl28cpld-wdt.yaml
> > > 
> > > diff --git
> > > a/Documentation/devicetree/bindings/gpio/kontron,sl28cpld-gpio.yaml
> > > b/Documentation/devicetree/bindings/gpio/kontron,sl28cpld-gpio.yaml
> > > new file mode 100644
> > > index 000000000000..9a63a158a796
> > > --- /dev/null
> > > +++
> > > b/Documentation/devicetree/bindings/gpio/kontron,sl28cpld-gpio.yaml
> > > @@ -0,0 +1,54 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/gpio/kontron,sl28cpld-gpio.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: GPIO driver for the sl28cpld board management controller
> > > +
> > > +maintainers:
> > > +  - Michael Walle <michael@...le.cc>
> > > +
> > > +description: |
> > > +  This module is part of the sl28cpld multi-function device. For more
> > > +  details see
> > > Documentation/devicetree/bindings/mfd/kontron,sl28cpld.yaml.
> > 
> > Paths are normally relative.
> 
> grep Documentation/ Documentation
> 
> I know there are a lot false positives (esp in the first one)..
> 
> $ grep -r "\.\./" Documentation | wc -l
> 1826
> $ grep -r "Documentation/" Documentation|wc -l
> 2862

I actually meant just for Device Tree bindings, but it does appear
that 'Documentation' is used a bunch there too.

My reasons for not liking full paths is that the intention was always
to move 'Documentation/devicetree' to a new location outside of the
kernel source tree.

[...]

> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/mfd/kontron,sl28cpld.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Kontron's sl28cpld board management controller
> > 
> > "S128CPLD" ?
> 
> still not, its sl28cpld, think of a project/code name, not the product
> appended with CPLD.
> 
> > "Board Management Controller (BMC)" ?
> 
> sounds like IPMI, which I wanted to avoid.

Is there a datasheet?

> > > +maintainers:
> > > +  - Michael Walle <michael@...le.cc>
> > > +
> > > +description: |
> > > +  The board management controller may contain different IP blocks
> > > like
> > > +  watchdog, fan monitoring, PWM controller, interrupt controller
> > > and a
> > > +  GPIO controller.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: kontron,sl28cpld-r1
> > 
> > We don't usually code revision numbers in compatible strings.
> > 
> > Is there any way to pull this from the H/W?
> 
> No, unfortunately you can't. And I really want to keep that, in case
> in the future there are some backwards incompatible changes.

Rob,

I know you reviewed this already, but you can give your opinion on
this specifically please?  I know that we have pushed back on this in
the past.


-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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