Re: [PATCH 5/5] of/clock: eliminate function __of_clk_get_from_provider

[Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>]

On Mon, Mar 14, 2011 at 09:18:42PM +0800, Shawn Guo wrote:
> With the platform clock support, the 'struct clk' should have been
> associated with device_node->data.  So the use of function
> __of_clk_get_from_provider can be eliminated.
> 
> Signed-off-by: Shawn Guo <shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
>  drivers/of/clock.c |   23 ++---------------------
>  1 files changed, 2 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/of/clock.c b/drivers/of/clock.c
> index 7b5ea67..f124d0a 100644
> --- a/drivers/of/clock.c
> +++ b/drivers/of/clock.c
> @@ -71,24 +71,6 @@ void of_clk_del_provider(struct device_node *np,
>  	mutex_unlock(&of_clk_lock);
>  }
>  
> -static struct clk *__of_clk_get_from_provider(struct device_node *np, const char *clk_output)
> -{
> -	struct of_clk_provider *provider;
> -	struct clk *clk = NULL;
> -
> -	/* Check if we have such a provider in our array */
> -	mutex_lock(&of_clk_lock);
> -	list_for_each_entry(provider, &of_clk_providers, link) {
> -		if (provider->node == np)
> -			clk = provider->get(np, clk_output, provider->data);
> -		if (clk)
> -			break;
> -	}
> -	mutex_unlock(&of_clk_lock);
> -
> -	return clk;
> -}
> -
>  struct clk *of_clk_get(struct device *dev, const char *id)
>  {
>  	struct device_node *provnode;
> @@ -123,9 +105,8 @@ struct clk *of_clk_get(struct device *dev, const char *id)
>  			__func__, prop_name, dev->of_node->full_name);
>  		return NULL;
>  	}
> -	clk = __of_clk_get_from_provider(provnode, prop);
> -	if (clk)
> -		dev_dbg(dev, "Using clock from %s\n", provnode->full_name);
> +
> +	clk = provnode->data;

Where is the device_node->data pointer getting set?

In general the ->data pointer of struct device_node should be avoided.
There are no strong rules about its usage which means there is a very
real risk that another driver or subsystem will try to use it for a
different purpose.  

Iterating over the whole device tree is safer, and it really isn't
very expensive.  If you really want to store the struct_clk pointer in
the device node, then it would be better to add a struct clk * field
to struct device_node.

g.