linux-kernel - Re: fwnode_for_each_child_node() and OF backend discrepancy

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Message-ID: <Yrrhs3D++V79/4Jk@smile.fi.intel.com>
Date:   Tue, 28 Jun 2022 14:10:43 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Michael Walle <michael@...le.cc>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-acpi@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: fwnode_for_each_child_node() and OF backend discrepancy

On Mon, Jun 27, 2022 at 02:49:51PM +0200, Michael Walle wrote:
> Hi,
> 
> I tired to iterate over all child nodes, regardless if they are available
> or not. Now there is that handy fwnode_for_each_child_node() (and the
> fwnode_for_each_available_child_node()). The only thing is the OF backend
> already skips disabled nodes [1], making fwnode_for_each_child_node() and
> fwnode_for_each_available_child_node() behave the same with the OF backend.
> 
> Doesn't seem to be noticed by anyone for now. I'm not sure how to fix that
> one. fwnode_for_each_child_node() and also fwnode_get_next_child_node() are
> used by a handful of drivers. I've looked at some, but couldn't decide
> whether they really want to iterate over all child nodes or just the enabled
> ones.
> 
> Any thoughts?

It was discussed at least twice this year (in regard to some new IIO drivers)
and Rob told that iterating over disabled (not available) nodes in OF kinda
legacy/design mistake. That's why device_for_each_child_node() goes only
over available nodes only.

So, why do you need to iterate over disabled ones?

-- 
With Best Regards,
Andy Shevchenko