[2/2] clk: rockchip: limit clock rate in the rockchip_fractional_approximation()

Commit Message

Alexander Kochetkov Dec. 21, 2017, 4:04 p.m. UTC

rockchip_fractional_approximation() can choose clock rate that can
be larger than one configured using clk_set_max_rate(). Request
to setup correct clock rate whose parent rate will be adjusted
to out of range value will fail with -EINVAL.

Fixes: commit 5d890c2df900 ("clk: rockchip: add special approximation
to fix up fractional clk's jitter").

Signed-off-by: Alexander Kochetkov <[e-mail]>
---
 drivers/clk/rockchip/clk.c |    7 +++++++
 1 file changed, 7 insertions(+)

Patch

diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c
index 35dbd63..3c1fb0d 100644
--- a/drivers/clk/rockchip/clk.c
+++ b/drivers/clk/rockchip/clk.c
@@ -175,6 +175,7 @@  static void rockchip_fractional_approximation(struct clk_hw *hw,
 {
 	struct clk_fractional_divider *fd = to_clk_fd(hw);
 	unsigned long p_rate, p_parent_rate;
+	unsigned long min_rate = 0, max_rate = 0;
 	struct clk_hw *p_parent;
 	unsigned long scale;
 
@@ -182,6 +183,12 @@  static void rockchip_fractional_approximation(struct clk_hw *hw,
 	if ((rate * 20 > p_rate) && (p_rate % rate != 0)) {
 		p_parent = clk_hw_get_parent(clk_hw_get_parent(hw));
 		p_parent_rate = clk_hw_get_rate(p_parent);
+		clk_hw_get_boundaries(clk_hw_get_parent(hw),
+			&min_rate, &max_rate);
+		if (p_parent_rate < min_rate)
+			p_parent_rate = min_rate;
+		if (p_parent_rate > max_rate)
+			p_parent_rate = max_rate;
 		*parent_rate = p_parent_rate;
 	}