Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754770Ab3C1KJ5 (ORCPT ); Thu, 28 Mar 2013 06:09:57 -0400 Received: from perceval.ideasonboard.com ([95.142.166.194]:45961 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753384Ab3C1KJ4 (ORCPT ); Thu, 28 Mar 2013 06:09:56 -0400 From: Laurent Pinchart To: Prabhakar Lad Cc: DLOS , LMML , LKML , Mauro Carvalho Chehab , Hans Verkuil , Sakari Ailus Subject: Re: [PATCH] davinci: vpif: add pm_runtime support Date: Thu, 28 Mar 2013 11:10:45 +0100 Message-ID: <3365178.uRYh2rr3nD@avalon> User-Agent: KMail/4.10 (Linux/3.7.10-gentoo; KDE/4.10.0; x86_64; ; ) In-Reply-To: References: <1364460632-21697-1-git-send-email-prabhakar.csengg@gmail.com> <1650338.UonQ4LqB70@avalon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2470 Lines: 71 Hi Prabhakar, On Thursday 28 March 2013 15:36:11 Prabhakar Lad wrote: > On Thu, Mar 28, 2013 at 2:39 PM, Laurent Pinchart wrote: > > On Thursday 28 March 2013 14:20:32 Prabhakar lad wrote: > >> From: Lad, Prabhakar > >> > >> Add pm_runtime support to the TI Davinci VPIF driver. > >> Along side this patch replaces clk_get() with devm_clk_get() > >> to simplify the error handling. > >> > >> Signed-off-by: Lad, Prabhakar > >> --- > >> > >> drivers/media/platform/davinci/vpif.c | 21 +++++++++++---------- > >> 1 files changed, 11 insertions(+), 10 deletions(-) > >> > >> diff --git a/drivers/media/platform/davinci/vpif.c > >> b/drivers/media/platform/davinci/vpif.c index 28638a8..7d14625 100644 > >> --- a/drivers/media/platform/davinci/vpif.c > >> +++ b/drivers/media/platform/davinci/vpif.c [snip] > >> @@ -439,12 +440,17 @@ static int vpif_probe(struct platform_device *pdev) > >> goto fail; > >> } > >> > >> - vpif_clk = clk_get(&pdev->dev, "vpif"); > >> + vpif_clk = devm_clk_get(&pdev->dev, "vpif"); > >> if (IS_ERR(vpif_clk)) { > >> status = PTR_ERR(vpif_clk); > >> goto clk_fail; > >> } > >> > >> - clk_prepare_enable(vpif_clk); > >> + clk_put(vpif_clk); > > > > Why do you need to call clk_put() here ? > > The above check is to see if the clock is provided, once done > we free it using clk_put(). In that case you shouldn't use devm_clk_get(), otherwise clk_put() will be called again automatically at remove() time. > >> + pm_runtime_enable(&pdev->dev); > >> + pm_runtime_resume(&pdev->dev); > >> + > >> + pm_runtime_get(&pdev->dev); > > > > Does runtime PM automatically handle your clock ? If so can't you remove > > clock handling from the driver completely ? > > Yes pm runtime take care of enabling/disabling the clocks > so that we don't have to do it in drivers. I believe clock > handling is removed with this patch, with just devm_clk_get() remaining ;) When is the clk_get() call expected to fail ? If the clock is provided by the SoC and always available, can't the check be removed completely ? -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/