clk: pass parent_rate into .set_rate

For most of .set_rate implementation, parent_rate will be used, so just
like passing parent_rate into .recalc_rate, let's pass parent_rate into
.set_rate too.

It also updates the kernel doc for .set_rate ops.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/clk-divider.c

@@ -111,14 +111,15 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
 	return *prate / div;
 }
 
-static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate)
+static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long parent_rate)
 {
 	struct clk_divider *divider = to_clk_divider(hw);
 	unsigned int div;
 	unsigned long flags = 0;
 	u32 val;
 
-	div = __clk_get_rate(__clk_get_parent(hw->clk)) / rate;
+	div = parent_rate / rate;
 
 	if (!(divider->flags & CLK_DIVIDER_ONE_BASED))
 		div--;

drivers/clk/clk.c

@@ -848,7 +848,7 @@ static void clk_change_rate(struct clk *clk)
 	old_rate = clk->rate;
 
 	if (clk->ops->set_rate)
-		clk->ops->set_rate(clk->hw, clk->new_rate);
+		clk->ops->set_rate(clk->hw, clk->new_rate, clk->parent->rate);
 
 	if (clk->ops->recalc_rate)
 		clk->rate = clk->ops->recalc_rate(clk->hw,

include/linux/clk-provider.h

@@ -88,19 +88,11 @@ struct clk_hw {
  * 		array index into the value programmed into the hardware.
  * 		Returns 0 on success, -EERROR otherwise.
  *
- * @set_rate:	Change the rate of this clock. If this callback returns
+ * @set_rate:	Change the rate of this clock. The requested rate is specified
- * 		CLK_SET_RATE_PARENT, the rate change will be propagated to the
+ *		by the second argument, which should typically be the return
- * 		parent clock (which may propagate again if the parent clock
+ *		of .round_rate call.  The third argument gives the parent rate
- * 		also sets this flag). The requested rate of the parent is
+ *		which is likely helpful for most .set_rate implementation.
- * 		passed back from the callback in the second 'unsigned long *'
+ *		Returns 0 on success, -EERROR otherwise.
- * 		argument.  Note that it is up to the hardware clock's set_rate
- * 		implementation to insure that clocks do not run out of spec
- * 		when propgating the call to set_rate up to the parent.  One way
- * 		to do this is to gate the clock (via clk_disable and/or
- * 		clk_unprepare) before calling clk_set_rate, then ungating it
- * 		afterward.  If your clock also has the CLK_GATE_SET_RATE flag
- * 		set then this will insure safety.  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
@@ -125,7 +117,8 @@ struct clk_ops {
 					unsigned long *);
 	int		(*set_parent)(struct clk_hw *hw, u8 index);
 	u8		(*get_parent)(struct clk_hw *hw);
-	int		(*set_rate)(struct clk_hw *hw, unsigned long);
+	int		(*set_rate)(struct clk_hw *hw, unsigned long,
+				    unsigned long);
 	void		(*init)(struct clk_hw *hw);
 };