Locking in the clk API, part 2: clk_prepare/clk_unprepare

[Russell King - ARM Linux]

On Fri, Feb 04, 2011 at 08:45:34PM +0800, Richard Zhao wrote:
> > == Implementation ==
> > 
> > Basically:
> > 
> > struct clk {
> > 	const struct clk_ops *ops
> > 	int                  enable_count;
> > 	spinlock_t           enable_lock;
> > 	int                  prepare_count;
> > 	struct mutex         prepare_lock;
> > };
> > 
> > int clk_enable(struct clk *clk)
> > {
> > 	int ret = 0;
> > 
> > 	spin_lock(&clk->enable_lock);
> > 	if (!clk->enable_count)
> > 		ret = clk->ops->enable(clk);
> > 
> > 	if (!ret)
> > 		clk->enable_count++;
> > 	spin_unlock(&clk->enable_lock);
> > 
> > 	return ret;
> > }
> Why do we not call parent's clk_enable in this function? For flexible? How many
> different cases is causing us to move the effert to platform clock driver?

You may notice that struct clk above doesn't have a parent.