clk: support hardware-specific debugfs entries

Add a new clk_ops->debug_init method to allow a clock hardware
driver to populate the clock's debugfs directory with entries
beyond those common for every clock.

Signed-off-by: Alex Elder <[e-mail]>
Signed-off-by: Mike Turquette <[e-mail]>

drivers/clk/clk.c

···
 	if (!d)
 		goto err_out;
 
+	if (clk->ops->debug_init)
+		if (clk->ops->debug_init(clk->hw, clk->dentry))
+			goto err_out;
+
 	ret = 0;
 	goto out;
 

include/linux/clk-provider.h

···
 #define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */
 
 struct clk_hw;
+struct dentry;
 
 /**
  * struct clk_ops -  Callback operations for hardware clocks; these are to
···
  *		separately via calls to .set_parent and .set_rate.
  *		Returns 0 on success, -EERROR otherwise.
  *
+ * @debug_init:	Set up type-specific debugfs entries for this clock.  This
+ *		is called once, after the debugfs directory entry for this
+ *		clock has been created.  The dentry pointer representing that
+ *		directory is provided as an argument.  Called with
+ *		prepare_lock held.  Returns 0 on success, -EERROR otherwise.
+ *
  *
  * The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow
  * implementations to split any work between atomic (enable) and sleepable
···
 	unsigned long	(*recalc_accuracy)(struct clk_hw *hw,
 					   unsigned long parent_accuracy);
 	void		(*init)(struct clk_hw *hw);
+	int		(*debug_init)(struct clk_hw *hw, struct dentry *dentry);
 };
 
 /**