From mboxrd@z Thu Jan 1 00:00:00 1970 From: MyungJoo Ham Subject: RE: Re: [PATCH v1] PM / devfreq: exynos-ppmu : Handle return value of clk_prepare_enable Date: Wed, 24 May 2017 01:30:36 +0000 Message-ID: <20170524013036epcms1p3f5ced11e6ebe5664ce70718dedcf8de1@epcms1p3> References: <592403E7.8060906@samsung.com> <1495191364-16015-1-git-send-email-arvind.yadav.cs@gmail.com> Reply-To: myungjoo.ham@samsung.com Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <592403E7.8060906@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Chanwoo Choi , Arvind Yadav , Kyungmin Park , "krzk@kernel.org" , "kgene@kernel.org" , "javier@osg.samsung.com" Cc: "linux-pm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-samsung-soc@vger.kernel.org" , "linux-kernel@vger.kernel.org" List-Id: linux-pm@vger.kernel.org > On 2017년 05월 19일 19:56, Arvind Yadav wrote: > > clk_prepare_enable() can fail here and we must check its return value. > > > > Signed-off-by: Arvind Yadav > > --- > > drivers/devfreq/event/exynos-ppmu.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/devfreq/event/exynos-ppmu.c b/drivers/devfreq/event/exynos-ppmu.c > > index 9b73509..8f6537a 100644 > > --- a/drivers/devfreq/event/exynos-ppmu.c > > +++ b/drivers/devfreq/event/exynos-ppmu.c > > @@ -648,7 +648,11 @@ static int exynos_ppmu_probe(struct platform_device *pdev) > > dev_name(&pdev->dev), desc[i].name); > > } > > > > - clk_prepare_enable(info->ppmu.clk); > > + ret = clk_prepare_enable(info->ppmu.clk); > > + if (ret) { > > + dev_err(&pdev->dev, "failed to prepare ppmu clock\n"); > > + return ret; > > + } > > You're right. But, actually, some ppmu device-tree node doesn't include > the clock information because exynos clk driver don't support the > clock for some ppmu devices. Until now, the clock of ppmu devices > are default on state. If it does not include the clock information, info->ppmu.clk is NULL, which makes ret == NULL, so this should be ok. (Line 593 of this file does that.) Acked-by: MyungJoo Ham (Applied to next-rc in devfreq tree) (same applies to exynos-nocp commit as well) Cheers, MyungJoo