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Date:   Tue, 25 Apr 2023 16:45:18 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Matti Vaittinen <mazziesaccount@gmail.com>
Cc:     Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Zhigang Shi <Zhigang.Shi@liteon.com>,
        Shreeya Patel <shreeya.patel@collabora.com>,
        Paul Gazzillo <paul@pgazz.com>,
        Dmitry Osipenko <dmitry.osipenko@collabora.com>,
        linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/5] iio: light: ROHM BU27008 color sensor
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On Tue, Apr 25, 2023 at 08:24:01AM +0300, Matti Vaittinen wrote:
> On 4/24/23 18:22, Andy Shevchenko wrote:
> > On Mon, Apr 24, 2023 at 04:10:09PM +0300, Matti Vaittinen wrote:

...

> > This...
> > 
> > > +#include <linux/bits.h>
> > 
> > ...is guaranteed to be included by this.
> > 
> > > +#include <linux/bitops.h>
> 
> Out of the curiosity - do we have a rule and rationale for explicitly
> including headers with 'stuff' we use Vs. trusting some header being
> included by another one? I've not thought much of this so I don't know if
> there are any pros/cons?

That's what we are starving for actually. Currently this is a tribe knowledge
which one gets while being involved into Linux kernel development for a long
time and being capable of keeping an eye on tree wide, library or similar
changes.

I would love to see some (preferably generated) list of the header
dependencies. Yet, the header dependency hell should be solved meanwhile
(see Ingo's 2k+ patch series).

-- 
With Best Regards,
Andy Shevchenko