Re: [PATCH v5 14/28] clk: Fix clk_get_parent() documentation

From: Maxime Ripard <maxime@cerno.tech>
To: Stephen Boyd <sboyd@kernel.org>
Cc: Mike Turquette <mturquette@baylibre.com>,
	linux-clk@vger.kernel.org,
	Yassine Oudjana <y.oudjana@protonmail.com>,
	Naresh Kamboju <naresh.kamboju@linaro.org>,
	Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Tony Lindgren <tony@atomide.com>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Alexander Stein <alexander.stein@ew.tq-group.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Jerome Brunet <jbrunet@baylibre.com>
Subject: Re: [PATCH v5 14/28] clk: Fix clk_get_parent() documentation
Date: Wed, 29 Jun 2022 15:12:56 +0200	[thread overview]
Message-ID: <20220629131256.vqk5t42r4paainsq@houat> (raw)
In-Reply-To: <20220629090545.52719C34114@smtp.kernel.org>

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Hi,

On Wed, Jun 29, 2022 at 02:05:43AM -0700, Stephen Boyd wrote:
> > diff --git a/include/linux/clk.h b/include/linux/clk.h
> > index 1507d5147898..39710b8453fa 100644
> > --- a/include/linux/clk.h
> > +++ b/include/linux/clk.h
> > @@ -755,8 +755,9 @@ int clk_set_parent(struct clk *clk, struct clk *parent);
> >   * clk_get_parent - get the parent clock source for this clock
> >   * @clk: clock source
> >   *
> > - * Returns struct clk corresponding to parent clock source, or
> > - * valid IS_ERR() condition containing errno.
> > + * Returns struct clk corresponding to parent clock source, a NULL
> > + * pointer if it doesn't have a parent, or a valid IS_ERR() condition
> > + * containing errno.
> 
> I'd rather not update this. A return value of NULL is a 'struct clk
> corresponding to parent clock source' already, and we don't want to
> document CCF implementation details in clk.h because there are other
> implementations of the API.

I find it slightly misleading still since using IS_ERR still doesn't get
you a safe pointer you can use.

I'll drop it though if you feel like it's too troublesome

Maxime

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