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References: <20220303173935.100622-1-cmirabil@redhat.com> <20220303173935.100622-7-cmirabil@redhat.com>
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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Thu, 10 Mar 2022 09:53:03 +0100
Message-ID: <CACRpkdawz3YgzccnCXV1auyBRHH-zhcxCa1dakBu3EMF0mG5Gg@mail.gmail.com>
Subject: Re: [PATCH v7 6/6] DO NOT MERGE: full sensehat device tree overlay
 for raspberry pi 4
To:     Charles Mirabile <cmirabil@redhat.com>
Cc:     linux-kernel@vger.kernel.org,
        Serge Schneider <serge@raspberrypi.org>,
        Stefan Wahren <stefan.wahren@i2se.com>,
        Nicolas Saenz Julienne <nsaenzju@redhat.com>,
        Mattias Brugger <mbrugger@suse.com>,
        linux-rpi-kernel@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, fedora-rpi@googlegroups.com,
        Mwesigwa Guma <mguma@redhat.com>,
        Joel Savitz <jsavitz@redhat.com>
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On Thu, Mar 3, 2022 at 6:43 PM Charles Mirabile <cmirabil@redhat.com> wrote:

> This patch should not be merged - dtbs files are not stored in the
> kernel tree. We just provide this file so the code can be tested.

A problem with that approach is that the DTS files are not reviewed
and that causes quality problems, and another problem is that the
kernel lack examples of real-world systems so people have to scout
to find those and that costs developer time.

I know many people are opposed to having this kind of stuff in the
kernel tree, but I am *for* having this kind of stuff in the kernel tree.

Mainly because there is no working community to shepherd it
otherwise, while we (the kernel maintainers) are still dependent on
there being one.

> +       lsm9ds1-magn@1c {
> +               compatible = "st,lsm9ds1-magn";
> +               reg = <0x1c>;
> +               status = "okay";
> +       };
> +
> +       lsm9ds1-accel@6a {
> +               compatible = "st,lsm9ds1-accel";
> +               reg = <0x6a>;
> +               status = "okay";
> +       };

These should typically have mounting matrices. I doubt they
are mounted according to the identity matrix, because electronics
designers usually have other concerns when layouting PCBs.

See
Documentation/devicetree/bindings/iio/mount-matrix.txt

Yours,
Linus Walleij

Yours,
Linus Walleij