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

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Date:	Thu, 22 Apr 2010 14:47:50 +0300
From:	Baruch Siach <baruch@...s.co.il>
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,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
Subject: Re: [PATCH] arm: mxc: utilise usecount field in clock operations

Hi Amit,

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

[snip]

> @@ -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);
> +	}

Unnecessary braces here. See chapter 3 of Documentation/CodingStyle.

> +
>  	mutex_lock(&clocks_mutex);
>  	ret = clk->set_parent(clk, parent);
> -	if (ret == 0)
> +	if (ret == 0) {
>  		clk->parent = parent;
> +	}

Ditto

>  	mutex_unlock(&clocks_mutex);
>  
> +	if (clk->usecount != 0) {
> +		clk_disable(prev_parent);
> +	}

Ditto

> +
>  	return ret;
>  }
>  EXPORT_SYMBOL(clk_set_parent);
> -- 

baruch

-- 
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   - baruch@...s.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
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