[PATCH 1/4] clk: Add a generic clock infrastructure

On Fri, 20 May 2011, Sascha Hauer wrote:

Hi Jeremy,

Nice to see progress in this area :)

On Fri, May 20, 2011 at 03:27:49PM +0800, Jeremy Kerr wrote:

quoted

+
+struct clk *clk_register(struct clk_hw_ops *ops, struct clk_hw *hw,
+		const char *name)
+{
+	struct clk *clk;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return NULL;
+
+	clk->name = name;
+	clk->ops = ops;
+	clk->hw = hw;
+	hw->clk = clk;

is it worth to add a CLK_REGISTERED flag here? Up to now clocks do not
have to be registered at all and the registering might be forgotten for
some clocks. I suppose funny things can happen when we operate on
unregistered clocks.

No, because not registered clocks are not accessible :)

 > +

quoted

+	/* Query the hardware for parent and initial rate */
+
+	if (clk->ops->get_parent)
+		/* We don't to lock against prepare/enable here, as
+		 * the clock is not yet accessible from anywhere */
+		clk->parent = clk->ops->get_parent(clk->hw);
+
+	if (clk->ops->recalc_rate)
+		clk->rate = clk->ops->recalc_rate(clk->hw);

This implicitely requires that we never register a clock before its
parent is registered. This makes perfect sense but I think we should
catch it here when the user tries to register a clock with a not yet
registered parent.

We can agree on that, but we can make it more clever than that.
 

quoted

+
+
+	return clk;
+}
+EXPORT_SYMBOL_GPL(clk_register);

BTW we planned to let the linker do the job of registering static
clocks, but this is only convenience and can be added later.

Right, you just need a helper function which runs through the list of
static stuff.