linux-kernel - Re: [RFC, PATCH 3/3] clk: add warnings for incorrect enable/prepare semantics

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Message-Id: <201102071608.42855.jeremy.kerr@canonical.com>
Date:	Mon, 7 Feb 2011 16:08:40 +0800
From:	Jeremy Kerr <jeremy.kerr@...onical.com>
To:	"Uwe Kleine-König" 
	<u.kleine-koenig@...gutronix.de>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Nicolas Pitre <nicolas.pitre@...aro.org>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	linux-sh@...r.kernel.org,
	Ben Herrenschmidt <benh@...nel.crashing.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Paul Mundt <lethal@...ux-sh.org>,
	Dima Zavin <dmitriyz@...gle.com>,
	Saravana Kannan <skannan@...eaurora.org>,
	Ben Dooks <ben-linux@...ff.org>,
	Russell King <linux@....linux.org.uk>
Subject: Re: [RFC, PATCH 3/3] clk: add warnings for incorrect enable/prepare semantics

Hi Uwe,

> This implies the warning is only issued on clocks that have a prepare
> callback.  If we want to enforce the new API the warning here shouldn't
> depend on clk->ops->prepare.  (clk_prepare and clk_unprepare need to
> be changed then to adapt the prepare_count even in the absence of
> clk->ops->prepare.)

Yeah, it's a decision about either adding a small cost to all clk_prepare()s 
(ie, adding cost when there is no prepare callback), or checking for the 
correct prepare/enable semantics for all clocks (even when it doesn't matter 
for that particular clock). I chose the first as more important, but happy to 
go either way here.

Cheers,


Jeremy
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