Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754712Ab0DVNB0 (ORCPT ); Thu, 22 Apr 2010 09:01:26 -0400 Received: from adelie.canonical.com ([91.189.90.139]:36092 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754687Ab0DVNBY (ORCPT ); Thu, 22 Apr 2010 09:01:24 -0400 Date: Thu, 22 Apr 2010 16:01:01 +0300 From: Amit Kucheria To: Sascha Hauer Cc: Russell King , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm: mxc: utilise usecount field in clock operations Message-ID: <20100422130101.GA2701@matterhorn.lan> Mail-Followup-To: Sascha Hauer , Russell King , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20100422115623.GR7882@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20100422115623.GR7882@pengutronix.de> X-URL: http://www.verdurent.com/ User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3755 Lines: 126 On 10 Apr 22, Sascha Hauer wrote: > On Wed, Apr 21, 2010 at 09:37:31PM +0300, Amit Kucheria wrote: > > clk->usecount can be used by platform code to check if a clock is active or > > not. > > The patch seems mostly fine but the commit log not. How about something like > 'This patch fixes the clock refcounting when reparenting is used.' > > A reference to > > http://www.spinics.net/lists/arm-kernel/msg85879.html > > might help aswell. Interesting. I had no idea about this work. I was just resurrecting old patches from January. Will fix and resend. /Amit > > > > Signed-off-by: Amit Kucheria > > --- > > arch/arm/plat-mxc/clock.c | 37 ++++++++++++++++++++++++------------- > > 1 files changed, 24 insertions(+), 13 deletions(-) > > > > diff --git a/arch/arm/plat-mxc/clock.c b/arch/arm/plat-mxc/clock.c > > index 323ff8c..c791f38 100644 > > --- a/arch/arm/plat-mxc/clock.c > > +++ b/arch/arm/plat-mxc/clock.c > > @@ -50,15 +50,15 @@ static DEFINE_MUTEX(clocks_mutex); > > > > static void __clk_disable(struct clk *clk) > > { > > - if (clk == NULL || IS_ERR(clk)) > > + if (clk == NULL || IS_ERR(clk) || !clk->usecount) > > return; > > > > - __clk_disable(clk->parent); > > - __clk_disable(clk->secondary); > > - > > - WARN_ON(!clk->usecount); > > - if (!(--clk->usecount) && clk->disable) > > - clk->disable(clk); > > + if (!(--clk->usecount)) { > > + if (clk->disable) > > + clk->disable(clk); > > + __clk_disable(clk->parent); > > + __clk_disable(clk->secondary); > > + } > > } > > > > static int __clk_enable(struct clk *clk) > > @@ -66,12 +66,13 @@ static int __clk_enable(struct clk *clk) > > if (clk == NULL || IS_ERR(clk)) > > return -EINVAL; > > > > - __clk_enable(clk->parent); > > - __clk_enable(clk->secondary); > > - > > - if (clk->usecount++ == 0 && clk->enable) > > - clk->enable(clk); > > + if (clk->usecount++ == 0) { > > + __clk_enable(clk->parent); > > + __clk_enable(clk->secondary); > > > > + if (clk->enable) > > + clk->enable(clk); > > + } > > return 0; > > } > > > > @@ -160,17 +161,27 @@ EXPORT_SYMBOL(clk_set_rate); > > int clk_set_parent(struct clk *clk, struct clk *parent) > > { > > int ret = -EINVAL; > > + struct clk *prev_parent = clk->parent; > > > > if (clk == NULL || IS_ERR(clk) || parent == NULL || > > IS_ERR(parent) || clk->set_parent == NULL) > > return ret; > > > > + if (clk->usecount != 0) { > > + clk_enable(parent); > > + } > > + > > mutex_lock(&clocks_mutex); > > ret = clk->set_parent(clk, parent); > > - if (ret == 0) > > + if (ret == 0) { > > clk->parent = parent; > > + } > > Please remove this hunk. It does not change anything except violating > the coding style. Also, please remove unnecessary braces. > > > mutex_unlock(&clocks_mutex); > > > > + if (clk->usecount != 0) { > > + clk_disable(prev_parent); > > + } > > + > > return ret; > > } > > EXPORT_SYMBOL(clk_set_parent); > > -- > > 1.7.0.4 > > > > > > -- > Pengutronix e.K. | | > Industrial Linux Solutions | http://www.pengutronix.de/ | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- ---------------------------------------------------------------------- Amit Kucheria, Kernel Engineer || amit.kucheria@canonical.com ---------------------------------------------------------------------- -- 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/