linux-kernel - Re: [PATCH v3] clk: add more managed APIs

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Message-ID: <20170214194408.GW25384@codeaurora.org>
Date:   Tue, 14 Feb 2017 11:44:08 -0800
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Russell King - ARM Linux <linux@...linux.org.uk>,
        Guenter Roeck <linux@...ck-us.net>,
        Michael Turquette <mturquette@...libre.com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] clk: add more managed APIs

On 02/06, Dmitry Torokhov wrote:
> On Mon, Jan 30, 2017 at 04:57:13PM -0800, Dmitry Torokhov wrote:
> > When converting a driver to managed resources it is desirable to be able to
> > manage all resources in the same fashion. This change allows managing clock
> > prepared and enabled state in the same way we manage many other resources.
> > 
> > This adds the following managed APIs:
> > 
> > - devm_clk_prepare()/devm_clk_unprepare();
> > - devm_clk_prepare_enable()/devm_clk_disable_unprepare().
> > 
> > Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
> 
> It would be awesome if we could get it into 4.11...

I'd prefer we didn't do this. Instead, make clk_put() drop any
prepare or enables that were done via that clk pointer. Mike
started to do this before[1], but we have some code that assumes
it can do:

	clk = clk_get(...)
	clk_prepare_enable(clk)
	clk_put(clk)

and have the clk stay on. Those would need to be changed.

We would also need Russell's approval to update the clk_put()
documentation to describe this change in behavior.

[1] http://lkml.kernel.org/r/1438974570-20812-1-git-send-email-mturquette@baylibre.com

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