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From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] clk: add more managed APIs
Date: Sat, 28 Jan 2017 11:22:07 -0800	[thread overview]
Message-ID: <20170128192207.GA38136@dtor-ws> (raw)
In-Reply-To: <20170128190309.GN27312@n2100.armlinux.org.uk>

On Sat, Jan 28, 2017 at 07:03:10PM +0000, Russell King - ARM Linux wrote:
> On Sat, Jan 28, 2017 at 10:40:47AM -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
> > clocks in the same way we manage many other resources.
> > 
> > This adds the following managed APIs:
> > 
> > - devm_clk_prepare()/devm_clk_unprepare();
> > - devm_clk_enable()/devm_clk_disable();
> > - devm_clk_prepare_enable()/devm_clk_disable_unprepare().
> 
> Does it make any sense what so ever to have devm_clk_enable() and
> devm_clk_disable()?
> 
> Take a moment to think about where you use all of these.  The devm_*
> functions are there to be used in probe functions so that cleanup
> paths can be streamlined and less erroneous.  They aren't for general
> use throughout the driver.
> 
> Given that, there are two operations that you may wish to do in the
> probe path:
> 
> 1. prepare a clock (avoiding the enable because you want to perform
>    the enable elsewhere in the driver.)
> 2. prepare and enable a clock
> 
> So, does having devm_clk_enable() really make sense?  I don't think
> it does, and I suspect they'll get very little if any use.  So, I
> think best not add them until someone comes up with a good and
> wide-spread use case.

That makes sense.

Guenter, I know you are a coccinelle wizard, can you cook a script that
can find current users of clk_enable() in probe paths? Then we can make
informed decision on devm_clk_enable.

Thanks!

-- 
Dmitry

  reply	other threads:[~2017-01-28 19:50 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-28 18:40 Dmitry Torokhov
2017-01-28 19:03 ` Russell King - ARM Linux
2017-01-28 19:22   ` Dmitry Torokhov [this message]
2017-01-28 21:44     ` Guenter Roeck
2017-01-28 23:39       ` Russell King - ARM Linux
2017-01-29 16:00         ` Guenter Roeck
2017-01-29 18:07         ` [PATCH v2] " Dmitry Torokhov
2017-01-29 18:31           ` Guenter Roeck
2017-01-30 18:55           ` Stephen Boyd
2017-01-30 19:22             ` Guenter Roeck
2017-01-30 21:42               ` Russell King - ARM Linux
2017-01-30 21:58                 ` Dmitry Torokhov
2017-01-30 22:25                   ` Russell King - ARM Linux
2017-01-30 22:51                 ` Guenter Roeck
2017-01-31  8:43                   ` Geert Uytterhoeven
2017-01-31  0:59               ` Dmitry Torokhov
2017-01-31 17:20                 ` Guenter Roeck
2017-01-31 18:26                   ` Dmitry Torokhov
2017-01-31 19:34                     ` Guenter Roeck
2017-01-31  0:57             ` [PATCH v3] " Dmitry Torokhov
2017-02-07  3:51               ` Dmitry Torokhov
2017-02-14 19:44                 ` Stephen Boyd
2017-02-14 19:55                   ` Dmitry Torokhov
2017-02-14 20:31                     ` Guenter Roeck
2017-02-14 20:01                   ` Russell King - ARM Linux

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