From mboxrd@z Thu Jan 1 00:00:00 1970 From: u.kleine-koenig@pengutronix.de (Uwe =?iso-8859-1?Q?Kleine-K=F6nig?=) Date: Thu, 18 Mar 2010 09:30:04 +0100 Subject: [PATCH 2/2 v2] [ARM] [IMX]: Fix clock use counter from underflow on multiple clk_disable(). In-Reply-To: <1268823811-9035-1-git-send-email-vzapolskiy@gmail.com> References: <20100317092042.GB16150@pengutronix.de> <1268823811-9035-1-git-send-email-vzapolskiy@gmail.com> Message-ID: <20100318083004.GA1369@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Vladimir, On Wed, Mar 17, 2010 at 02:03:31PM +0300, Vladimir Zapolskiy wrote: > If clk_disable() is called for already disabled clock clk->usecount > value is decremented anyway. This leads to a problem that sequent > clk_enable() call doesn't enable the clock as expected. > > Signed-off-by: Vladimir Zapolskiy > Cc: Sascha Hauer > Cc: Uwe Kleine-K?nig > --- > arch/arm/plat-mxc/clock.c | 6 +++++- > 1 files changed, 5 insertions(+), 1 deletions(-) > > diff --git a/arch/arm/plat-mxc/clock.c b/arch/arm/plat-mxc/clock.c > index 2daec3c..3189275 100644 > --- a/arch/arm/plat-mxc/clock.c > +++ b/arch/arm/plat-mxc/clock.c > @@ -53,10 +53,14 @@ static void __clk_disable(struct clk *clk) > if (clk == NULL || IS_ERR(clk)) > return; > > + if (!clk->usecount) { > + WARN(1, "Trying to disable a clock with 0 usecount\n"); > + return; > + } > + The advantage of just using WARN(!clk->usecount, "Trying to disable a disabled clock\n"); is that the error isn't caught and so is more likely to be fixed :-) I'n not a native English speaker, but I think "Trying to disable a clock with 0 usecount" isn't a proper English sentence. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ |