Re: [PATCH v2 1/3] dt-bindings: chrome: Add ChromeOS fingerprint binding

From: Stephen Boyd <swboyd@chromium.org>
To: Benson Leung <bleung@chromium.org>,
	Krzysztof Kozlowski <krzk@kernel.org>
Cc: linux-kernel@vger.kernel.org, chrome-platform@lists.linux.dev,
	 Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org,  Guenter Roeck <groeck@chromium.org>,
	Douglas Anderson <dianders@chromium.org>,
	 Craig Hesling <hesling@chromium.org>,
	Tom Hughes <tomhughes@chromium.org>,
	 Alexandru M Stan <amstan@chromium.org>,
	Tzung-Bi Shih <tzungbi@kernel.org>
Subject: Re: [PATCH v2 1/3] dt-bindings: chrome: Add ChromeOS fingerprint binding
Date: Thu, 17 Mar 2022 14:47:53 -0400	[thread overview]
Message-ID: <CAE-0n536LcZcLFRhWr1k8yho0u_6FD1AtpPyZfv+Mmh17bGt5Q@mail.gmail.com> (raw)
In-Reply-To: <3828e37f-f8e0-8473-537c-8e47cd5df8c6@kernel.org>

Quoting Krzysztof Kozlowski (2022-03-17 02:34:31)
> On 17/03/2022 01:58, Stephen Boyd wrote:
> > Add a binding to describe the fingerprint processor found on Chromebooks
> > with a fingerprint sensor.
> >
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: <devicetree@vger.kernel.org>
> > Cc: Guenter Roeck <groeck@chromium.org>
> > Cc: Douglas Anderson <dianders@chromium.org>
> > Cc: Craig Hesling <hesling@chromium.org>
> > Cc: Tom Hughes <tomhughes@chromium.org>
> > Cc: Alexandru M Stan <amstan@chromium.org>
> > Cc: Tzung-Bi Shih <tzungbi@kernel.org>
> > Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> > ---
> >  .../bindings/chrome/google,cros-ec-fp.yaml    | 85 +++++++++++++++++++
> >  1 file changed, 85 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/chrome/google,cros-ec-fp.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/chrome/google,cros-ec-fp.yaml b/Documentation/devicetree/bindings/chrome/google,cros-ec-fp.yaml
> > new file mode 100644
> > index 000000000000..ba4212e6b583
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/chrome/google,cros-ec-fp.yaml
>
> Hm, so chrome starts to be its own subsystem? I see USB connector
> bindings are already there, instead of usb directory.
>
> Is there anything special about Chrome that it is equal to subsystem or
> architecture? Once second file ends up there, this will encourage more
> of such patterns.

I don't see a problem.

>
> > @@ -0,0 +1,85 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/chrome/google,cros-ec-fp.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: ChromeOS Embedded Fingerprint Controller
> > +
> > +description:
> > +  Google's ChromeOS embedded fingerprint controller is a device which
> > +  implements fingerprint functionality such as unlocking a Chromebook
> > +  without typing a password.
> > +
> > +maintainers:
> > +  - Tom Hughes <tomhughes@chromium.org>
> > +
> > +properties:
> > +  compatible:
> > +    const: google,cros-ec-fp
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  spi-max-frequency:
> > +    maximum: 3000000
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  reset-gpios: true
> > +  boot0-gpios:
> > +    maxItems: 1
> > +    description: Assert for bootloader mode.
> > +
> > +  vdd-supply: true
> > +
> > +  google,cros-ec-spi-pre-delay:
>
> Use proper unit suffix, so "-us". No need for type then.
>

This is copy pasted from the cros-ec binding and the driver is already
looking for this property. Given that, there's no need to have this here
right now as we can always add this to the binding when/if it is needed.
I mostly put this here for completeness. I'll remove it.