From: Russell King <rmk+ker...@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+ker...@arm.linux.org.uk>
(cherry picked from commit d2d14a77886485310ec66e575f00ea5232ac7a14)
Signed-off-by: Yong, Jonathan <jonathan.y...@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
--
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