[linux-yocto] [PATCH 6/7] clk: update clk API documentation to clarify clk_round_rate()

[Yong, Jonathan]

From: Russell King <rmk+kernel at arm.linux.org.uk>

The idea is that rate = clk_round_rate(clk, r) is equivalent to:

	clk_set_rate(clk, r);
	rate = clk_get_rate(clk);

except that clk_round_rate() does not change the hardware in any way.

Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
(cherry picked from commit d2d14a77886485310ec66e575f00ea5232ac7a14)
Signed-off-by: Yong, Jonathan <jonathan.yong at intel.com>
---
 include/linux/clk.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/clk.h b/include/linux/clk.h
index 68c16a6..cafb22d 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -306,6 +306,20 @@ void devm_clk_put(struct device *dev, struct clk *clk);
  * @clk: clock source
  * @rate: desired clock rate in Hz
  *
+ * This answers the question "if I were to pass @rate to clk_set_rate(),
+ * what clock rate would I end up with?" without changing the hardware
+ * in any way.  In other words:
+ *
+ *   rate = clk_round_rate(clk, r);
+ *
+ * and:
+ *
+ *   clk_set_rate(clk, r);
+ *   rate = clk_get_rate(clk);
+ *
+ * are equivalent except the former does not modify the clock hardware
+ * in any way.
+ *
  * Returns rounded clock rate in Hz, or negative errno.
  */
 long clk_round_rate(struct clk *clk, unsigned long rate);
-- 
2.4.10