From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Tue, 8 Mar 2016 20:50:51 +0000
Subject: [PATCH] ARM: mvebu: Fix of_clk_get() call in a non sleeping
 context
In-Reply-To: <8760wx3oy4.fsf@free-electrons.com>
References: <1457446733-7137-1-git-send-email-gregory.clement@free-electrons.com>
 <20160308164117.2a3ed3a7@free-electrons.com>
 <87a8m93pt0.fsf@free-electrons.com>
 <20160308173134.22a3ad64@free-electrons.com>
 <8760wx3oy4.fsf@free-electrons.com>
Message-ID: <20160308205050.GN19428@n2100.arm.linux.org.uk>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Mar 08, 2016 at 05:38:11PM +0100, Gregory CLEMENT wrote:
> And from clk_enable comment we have:
> ""
> clk_enable must not sleep, which differentiates it from clk_prepare.  In a
> simple case, clk_enable can be used instead of clk_prepare to ungate a clk
> if the operation will never sleep.
> ""
> 
> Moreoever for me the "must" was to insist to the order of the call no to
> the fact that both must be called.

As the author of the clk API, the idea here is that clk_prepare()
should always be called _before_ clk_enable() for any clock: in
other words, getting a clock and then calling clk_enable() on it
is not legal.

CCF presently enforces this - clk_enable() without a preceding
clk_prepare() will return -ESHUTDOWN.

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