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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-03-14 15:12:35 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-05-06 11:58:10 +0100
commitd2d14a77886485310ec66e575f00ea5232ac7a14 (patch)
tree1bde5a546fc78058703552c28cdefd0061130d01 /include/linux/clk.h
parentd5622a9c13752be46e6fcde9d31391ce0bb0598b (diff)
clk: update clk API documentation to clarify clk_round_rate()
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@arm.linux.org.uk>
Diffstat (limited to 'include/linux/clk.h')
-rw-r--r--include/linux/clk.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 68c16a6bedb3..cafb22df8d00 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);