linux-kernel - Re: [PATCH v2 1/2] clk: track the orphan status of clocks and their children

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Message-ID: <55357DD8.6060200@codeaurora.org>
Date:	Mon, 20 Apr 2015 15:29:44 -0700
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Heiko Stübner <heiko@...ech.de>,
	Mike Turquette <mturquette@...aro.org>
CC:	dianders@...omium.org, linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
	linux@....linux.org.uk
Subject: Re: [PATCH v2 1/2] clk: track the orphan status of clocks and their
 children

On 04/12/15 04:37, Heiko Stübner wrote:
> While children of orphan clocks are not carried in the orphan-list itself,
> they're nevertheless orphans in their own right as they also don't have an
> input-rate available. To ease tracking if a clock is an orphan or has an
> orphan in its parent path introduce an orphan field into struct clk and
> update it and the fields in child-clocks when a clock gets added or removed
> from the orphan-list.
>
> Suggested-by: Stephen Boyd <sboyd@...eaurora.org>
> Signed-off-by: Heiko Stuebner <heiko@...ech.de>

Just nitpicks. Otherwise it looks good to me.

> ---
>  drivers/clk/clk.c | 33 ++++++++++++++++++++++++++++++---
>  1 file changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index f85c8e2..a9fa5ab 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -62,6 +62,7 @@ struct clk_core {
>  	struct clk_core		*new_parent;
>  	struct clk_core		*new_child;
>  	unsigned long		flags;
> +	bool			orphan;
>  	unsigned int		enable_count;
>  	unsigned int		prepare_count;
>  	unsigned long		accuracy;
> @@ -1433,18 +1434,40 @@ static int clk_fetch_parent_index(struct clk_core *clk,
>  	return -EINVAL;
>  }
>  
> +/*
> + * Update the orphan status of @clk and all its children.
> + */
> +static void clk_update_orphan_status(struct clk_core *clk, int is_orphan)

Please s/clk/core/ here because it's a new function (yeah we've been
slow and haven't updated the whole file to do this consistently). Also
use bool for is_orphan.

> +{
> +	struct clk_core *child;
> +
> +	clk->orphan = is_orphan;
> +
> +	hlist_for_each_entry(child, &clk->children, child_node)
> +		clk_update_orphan_status(child, is_orphan);
> +}
> +
>  static void clk_reparent(struct clk_core *clk, struct clk_core *new_parent)
>  {
> +	bool was_orphan = clk->orphan;
> +
>  	hlist_del(&clk->child_node);
>  
>  	if (new_parent) {
> +		bool becomes_orphan = new_parent->orphan;
> +
>  		/* avoid duplicate POST_RATE_CHANGE notifications */
>  		if (new_parent->new_child == clk)
>  			new_parent->new_child = NULL;
>  
>  		hlist_add_head(&clk->child_node, &new_parent->children);
> +
> +		if (was_orphan != becomes_orphan)
> +			clk_update_orphan_status(clk, becomes_orphan);
>  	} else {
>  		hlist_add_head(&clk->child_node, &clk_orphan_list);
> +		if (!was_orphan)
> +			clk_update_orphan_status(clk, 1);

Please use true here.

>  	}
>  
>  	clk->parent = new_parent;
> @@ -2348,13 +2371,17 @@ static int __clk_init(struct device *dev, struct clk *clk_user)
>  	 * clocks and re-parent any that are children of the clock currently
>  	 * being clk_init'd.
>  	 */
> -	if (clk->parent)
> +	if (clk->parent) {
>  		hlist_add_head(&clk->child_node,
>  				&clk->parent->children);
> -	else if (clk->flags & CLK_IS_ROOT)
> +		clk->orphan = clk->parent->orphan;
> +	} else if (clk->flags & CLK_IS_ROOT) {
>  		hlist_add_head(&clk->child_node, &clk_root_list);
> -	else
> +		clk->orphan = 0;
> +	} else {
>  		hlist_add_head(&clk->child_node, &clk_orphan_list);
> +		clk->orphan = 1;

Please use true/false here.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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