Re: [PATCH 1/2] dt-bindings: mfd: Add ChromeOS fingerprint binding

From: Stephen Boyd <swboyd@chromium.org>
To: Alexandru M Stan <amstan@chromium.org>
Cc: Benson Leung <bleung@chromium.org>,
	linux-kernel <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>
Subject: Re: [PATCH 1/2] dt-bindings: mfd: Add ChromeOS fingerprint binding
Date: Tue, 15 Mar 2022 10:50:34 -0500	[thread overview]
Message-ID: <CAE-0n50A2yrSbQJA8EMum3AoLf+w263ddFh6sA5d+tfMMMkarA@mail.gmail.com> (raw)
In-Reply-To: <CAHNYxRwFYBbgxUqz79jYXbDxSd-r+NdHWQPucEyuNK83U577xw@mail.gmail.com>

Quoting Alexandru M Stan (2022-03-14 17:23:38)
> On Mon, Mar 14, 2022 at 4:22 PM Stephen Boyd <swboyd@chromium.org> wrote:
> >
> > +        compatible = "google,cros-ec-fp";
> > +        reg = <0>;
> > +        interrupt-parent = <&gpio_controller>;
> > +        interrupts = <4 IRQ_TYPE_LEVEL_LOW>;
> > +        spi-max-frequency = <3000000>;
> > +        google,cros-ec-spi-msg-delay = <37>;
> > +        google,cros-ec-spi-pre-delay = <5>;
> > +        reset-gpios = <&gpio_controller 5 GPIO_ACTIVE_LOW>;
> > +        boot0-gpios = <&gpio_controller 10 GPIO_ACTIVE_LOW>;
> This should say GPIO_ACTIVE_HIGH, since there's no inverting going on
> either with a real inverter, or the convention (of 'N' being in the
> pin name).
>
> It might be easier to reason about if there's no invesion going for this signal.
>
> Consider it like an enum instead of a verb (unlike active_low
> reset-gpios which can be considered: in reset if it's set):
>
> enum boot0 {
>         normal = 0,
>         bootloader = 1,
> };

Ok got it! I have in my notes that physically high line means normal
boot mode and physically low is bootloader mode. I confused myself. I'll
fix this.