linux-kernel - Re: [PATCH] arm/tegra: clk

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Message-ID: <20111025170038.GT1001@tbergstrom-lnx.Nvidia.com>
Date:	Tue, 25 Oct 2011 20:00:38 +0300
From:	Peter De Schrijver <pdeschrijver@...dia.com>
To:	Joe Perches <joe@...ches.com>
CC:	Colin Cross <ccross@...roid.com>, Olof Johansson <olof@...om.net>,
	Stephen Warren <swarren@...dia.com>,
	Russell King <linux@....linux.org.uk>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] arm/tegra: clk_get should not be fatal

On Tue, Oct 25, 2011 at 06:26:08PM +0200, Joe Perches wrote:
> On Tue, 2011-10-25 at 19:15 +0300, pdeschrijver@...dia.com wrote:
> > The timer and rtc-timer clocks aren't gated by default, so there is no reason
> > to crash the system if the dummy enable call failed.
> []
> > diff --git a/arch/arm/mach-tegra/timer.c b/arch/arm/mach-tegra/timer.c
> []
> > @@ -186,16 +186,20 @@ static void __init tegra_init_timer(void)
> >  	int ret;
> >  
> >  	clk = clk_get_sys("timer", NULL);
> > -	BUG_ON(IS_ERR(clk));
> > -	clk_enable(clk);
> > +	if (IS_ERR(clk))
> > +		pr_warning("Unable to get timer clock");
> > +	else
> > +		clk_enable(clk);
> >  
> >  	/*
> >  	 * rtc registers are used by read_persistent_clock, keep the rtc clock
> >  	 * enabled
> >  	 */
> >  	clk = clk_get_sys("rtc-tegra", NULL);
> > -	BUG_ON(IS_ERR(clk));
> > -	clk_enable(clk);
> > +	if (IS_ERR(clk))
> > +		pr_warning("Unable to get rtc-tegra clock");
> > +	else
> > +		clk_enable(clk);
> 
> Are these messages are really necessary?

I think it's still useful to have them as not having a clock fw is a strange
situation. It's not fatal though, but worth a warning I would say.

> Maybe just:
> 	if (!IS_ERR(clk))
> 		clk_enable(clk)
> 
> If these are really necessary, please use
> 	pr_warn("Unable to get <foo>\n");
> pr_warn and with a terminating newline.
> 

Is pr_warn any different then pr_warning? Point taken about the newline.

Cheers,

Peter.
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