clk: add function documentation for clk_hw_round_rate()

Information about usage and prerequisites for this API.
Signed-off-by: Sarang Mairal <sarangmairal@gmail.com>
Link: https://lore.kernel.org/r/20200611021941.786-2-sarangmairal@gmail.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk.c

@@ -1400,6 +1400,21 @@ int __clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
 }
 EXPORT_SYMBOL_GPL(__clk_determine_rate);
 
+/**
+ * clk_hw_round_rate() - round the given rate for a hw clk
+ * @hw: the hw clk for which we are rounding a rate
+ * @rate: the rate which is to be rounded
+ *
+ * Takes in a rate as input and rounds it to a rate that the clk can actually
+ * use.
+ *
+ * Context: prepare_lock must be held.
+ *          For clk providers to call from within clk_ops such as .round_rate,
+ *          .determine_rate.
+ *
+ * Return: returns rounded rate of hw clk if clk supports round_rate operation
+ *         else returns the parent rate.
+ */
 unsigned long clk_hw_round_rate(struct clk_hw *hw, unsigned long rate)
 {
 	int ret;