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From:   Rob Herring <robh@kernel.org>
Date:   Thu, 31 May 2018 10:58:59 -0500
Message-ID: <CAL_JsqLfqgUbzMWdE_c96DrdgB31gSixbJo+JvsZhoJGJRWYMw@mail.gmail.com>
Subject: Re: [PATCH v2 4/8] dt-bindings: gnss: add u-blox binding
To:     Johan Hovold <johan@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Andreas Kemnade <andreas@kemnade.info>,
        Arnd Bergmann <arnd@arndb.de>,
        "H . Nikolaus Schaller" <hns@goldelico.com>,
        Pavel Machek <pavel@ucw.cz>,
        Marcel Holtmann <marcel@holtmann.org>,
        Sebastian Reichel <sebastian.reichel@collabora.co.uk>,
        Tony Lindgren <tony@atomide.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        devicetree@vger.kernel.org
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On Thu, May 31, 2018 at 9:34 AM, Johan Hovold <johan@kernel.org> wrote:
> On Thu, May 31, 2018 at 08:55:10AM -0500, Rob Herring wrote:
>> On Thu, May 31, 2018 at 3:22 AM, Johan Hovold <johan@kernel.org> wrote:
>> > On Wed, May 30, 2018 at 10:58:05PM -0500, Rob Herring wrote:
>> >> On Wed, May 30, 2018 at 12:32:38PM +0200, Johan Hovold wrote:
>> >> > Add binding for u-blox GNSS receivers.
>> >> >
>> >> > Note that the u-blox product names encodes form factor (e.g. "neo"),
>> >> > chipset (e.g. "8") and variant (e.g. "q"), but that only formfactor and
>> >> > chipset is used for the compatible strings (for now).
>> >> >
>> >> > Signed-off-by: Johan Hovold <johan@kernel.org>
>> >> > ---
>> >> >  .../devicetree/bindings/gnss/u-blox.txt       | 44 +++++++++++++++++++
>> >> >  .../devicetree/bindings/vendor-prefixes.txt   |  1 +
>> >> >  2 files changed, 45 insertions(+)
>> >> >  create mode 100644 Documentation/devicetree/bindings/gnss/u-blox.txt
>> >> >
>> >> > diff --git a/Documentation/devicetree/bindings/gnss/u-blox.txt b/Documentation/devicetree/bindings/gnss/u-blox.txt
>> >> > new file mode 100644
>> >> > index 000000000000..caef9ace0b0c
>> >> > --- /dev/null
>> >> > +++ b/Documentation/devicetree/bindings/gnss/u-blox.txt
>> >> > @@ -0,0 +1,44 @@
>> >> > +u-blox GNSS Receiver DT binding
>> >> > +
>> >> > +The u-blox GNSS receivers can use UART, DDC (I2C), SPI and USB interfaces.
>> >> > +
>> >> > +Please see Documentation/devicetree/bindings/gnss/gnss.txt for generic
>> >> > +properties.
>> >> > +
>> >> > +Required properties:
>> >> > +
>> >> > +- compatible       : Must be one of
>> >>
>> >> mixture of space and tab here.
>> >
>> > Oops. Same single space character before the tab here in all three
>> > binding docs (and in the in-tree slave_devices.txt which I think I used
>> > as a template).
>>
>> Who wrote that crap? ;)
>
> Heh.
>
>> >
>> >> > +
>> >> > +                   "u-blox,neo-8"
>> >> > +                   "u-blox,neo-m8"
>> >> > +
>> >> > +- vcc-supply       : Main voltage regulator
>> >> > +
>> >> > +Required properties (DDC):
>> >> > +- reg              : DDC (I2C) slave address
>> >> > +
>> >> > +Required properties (SPI):
>> >> > +- reg              : SPI chip select address
>> >> > +
>> >> > +Required properties (USB):
>> >> > +- reg              : Number of the USB hub port or the USB host-controller port
>> >> > +                  to which this device is attached
>> >> > +
>> >> > +Optional properties:
>> >> > +
>> >> > +- timepulse-gpios  : Time pulse GPIO
>> >> > +- u-blox,extint-gpios      : External interrupt GPIO
>> >>
>> >> This should be interrupts property instead of a gpio.
>> >
>> > Contrary to what the name may suggest, this pin is actually an input
>> > which can be used to control active power or to provide time or
>> > frequency aiding data to the receiver (see section 1.13 in [1]).
>> >
>> > I only added it for completeness as the driver does not use it
>> > currently. Remove, leave as is, or add "input" to the description as in:
>> >
>> >         - u-blox,extint-gpios   : External interrupt input GPIO
>>
>> Yes. You should also define the active level.
>
> The active level appears to be runtime configurable and dependent on the
> selected function. For power control it can be used to control force-on
> (active high), force-off (active low) or both; and for time aiding
> sampling on falling or rising edge is also configurable. And who knows
> what else this pin is used for next time they update the firmware. ;)

Okay.

> Shall I remove the property, or just add "input" as suggested above?

Just add "input".

Rob