clk: add clk_round_rate()

It returns the rate which will be set if you ask clk_set_rate() to set
that rate. It provides a way to query exactly what rate you'll get if
you call clk_set_rate() with that same argument.
So essentially, clk_round_rate() and clk_set_rate() are equivalent
except the former does not modify the clock hardware in any way.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Sean Anderson <seanga2@gmail.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 5cfd00ce77..b75056718b 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -523,6 +523,21 @@ long long clk_get_parent_rate(struct clk *clk)
 	return pclk->rate;
 }
 
+ulong clk_round_rate(struct clk *clk, ulong rate)
+{
+	const struct clk_ops *ops;
+
+	debug("%s(clk=%p, rate=%lu)\n", __func__, clk, rate);
+	if (!clk_valid(clk))
+		return 0;
+
+	ops = clk_dev_ops(clk->dev);
+	if (!ops->round_rate)
+		return -ENOSYS;
+
+	return ops->round_rate(clk, rate);
+}
+
 ulong clk_set_rate(struct clk *clk, ulong rate)
 {
 	const struct clk_ops *ops;