[PATCH v1] clk: mux: check value returned from clk_mux_val_to_index()

[Maksim Kiselev <bigunclemax@gmail.com>]

The clk_mux_val_to_index() may return -EINVAL. In this case
clk_mux_get_parent() will return a wrong parent index and
this will lead to out of bounds error.

E.g. when we register mux clk:
	ret = clk_register(clk, UBOOT_DM_CLK_CCF_MUX, name,
			   parent_names[clk_mux_get_parent(clk)]);

Let's add a check on the return value of clk_mux_val_to_index() and if
it's negative, set parent index to 0.

Signed-off-by: Maksim Kiselev <bigunclemax@gmail.com>
---
 drivers/clk/clk-mux.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c
index 017f25f7a5..00fe916171 100644
--- a/drivers/clk/clk-mux.c
+++ b/drivers/clk/clk-mux.c
@@ -88,6 +88,7 @@ unsigned int clk_mux_index_to_val(u32 *table, unsigned int flags, u8 index)
 u8 clk_mux_get_parent(struct clk *clk)
 {
 	struct clk_mux *mux = to_clk_mux(clk);
+	int index;
 	u32 val;
 
 #if IS_ENABLED(CONFIG_SANDBOX_CLK_CCF)
@@ -98,7 +99,13 @@ u8 clk_mux_get_parent(struct clk *clk)
 	val >>= mux->shift;
 	val &= mux->mask;
 
-	return clk_mux_val_to_index(clk, mux->table, mux->flags, val);
+	index = clk_mux_val_to_index(clk, mux->table, mux->flags, val);
+	if (index < 0) {
+		log_err("Could not fetch index\n");
+		index = 0;
+	}
+
+	return index;
 }
 
 static int clk_fetch_parent_index(struct clk *clk,
-- 
2.39.2