From mboxrd@z Thu Jan  1 00:00:00 1970
From: s.hauer@pengutronix.de (Sascha Hauer)
Date: Wed, 2 May 2012 11:51:08 +0200
Subject: [PATCH 1/3] clk: always pass parent_rate into .round_rate
In-Reply-To: <1334235019-15553-1-git-send-email-shawn.guo@linaro.org>
References: <1334192572-12499-1-git-send-email-mturquette@linaro.org>
 <1334235019-15553-1-git-send-email-shawn.guo@linaro.org>
Message-ID: <20120502095108.GF20478@pengutronix.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, Apr 12, 2012 at 08:50:17PM +0800, Shawn Guo wrote:
> The parent_rate will likely be used by most .round_rate implementation
> no matter whether flag CLK_SET_RATE_PARENT is set or not, so let's
> always pass parent_rate into .round_rate.
> 
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> ---
>  drivers/clk/clk-divider.c |   12 +++---------
>  drivers/clk/clk.c         |   16 +++++++---------
>  2 files changed, 10 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> index add784b..04439f1 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -67,8 +67,8 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>  	if (divider->flags & CLK_DIVIDER_ONE_BASED)
>  		maxdiv--;
>  
> -	if (!best_parent_rate) {
> -		parent_rate = __clk_get_rate(__clk_get_parent(hw->clk));
> +	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
> +		parent_rate = *best_parent_rate;
>  		bestdiv = DIV_ROUND_UP(parent_rate, rate);
>  		bestdiv = bestdiv == 0 ? 1 : bestdiv;
>  		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
> @@ -108,13 +108,7 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
>  	int div;
>  	div = clk_divider_bestdiv(hw, rate, prate);
>  
> -	if (prate)
> -		return *prate / div;
> -	else {
> -		unsigned long r;
> -		r = __clk_get_rate(__clk_get_parent(hw->clk));
> -		return r / div;
> -	}
> +	return *prate / div;
>  }
>  
>  static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate)
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index af2bf12..19caa0a 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -582,7 +582,7 @@ EXPORT_SYMBOL_GPL(clk_get_rate);
>   */
>  unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
>  {
> -	unsigned long unused;
> +	unsigned long parent_rate = 0;
>  
>  	if (!clk)
>  		return -EINVAL;
> @@ -590,10 +590,10 @@ unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
>  	if (!clk->ops->round_rate)
>  		return clk->rate;
>  
> -	if (clk->flags & CLK_SET_RATE_PARENT)
> -		return clk->ops->round_rate(clk->hw, rate, &unused);
> -	else
> -		return clk->ops->round_rate(clk->hw, rate, NULL);
> +	if (clk->parent)
> +		parent_rate = clk->parent->rate;
> +
> +	return clk->ops->round_rate(clk->hw, rate, &parent_rate);
>  }
>  
>  /**
> @@ -763,7 +763,7 @@ static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
>  static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
>  {
>  	struct clk *top = clk;
> -	unsigned long best_parent_rate;
> +	unsigned long best_parent_rate = 0;
>  	unsigned long new_rate;
>  
>  	/* sanity */
> @@ -775,9 +775,6 @@ static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
>  		if (!clk->ops->round_rate) {
>  			clk->new_rate = clk->rate;
>  			return NULL;
> -		} else {
> -			new_rate = clk->ops->round_rate(clk->hw, rate, NULL);
> -			goto out;
>  		}
>  	}


This patch allows a clk to change a parent clk rate even when
CLK_SET_RATE_PARENT is not set.

Before this patch we used to pass a NULL pointer as parent clk rate when
a clk was not allowed to change a parent rate. Now we rely on the
goodwill of the clk not changing the parent rate. I'll prepare a patch
catching this in the framework.

Sascha


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