linux-kernel - Re: [PATCH] arm: mxc: utilise usecount field in clock operations

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Date:	Thu, 22 Apr 2010 16:37:44 +0200
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Amit Kucheria <amit.kucheria@...onical.com>
Cc:	Sascha Hauer <s.hauer@...gutronix.de>,
	Russell King <linux@....linux.org.uk>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] arm: mxc: utilise usecount field in clock operations

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.
> 
> Signed-off-by: Amit Kucheria <amit.kucheria@...onical.com>
> ---
>  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);
> +	}
>  }
This removes the WARN_ON if the clock is already off.  Is this intended?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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