[PATCH 2/2] clk: mediatek: fix parent rate lookup for fixed PLL clocks

[Weijie Gao]

From: Sam Shih <sam.shih at mediatek.com>

The refactoring in commit 00d0ff7f81bf ("clk: mediatek: refactor parent
rate lookup functions") introduced a regression where fixed PLL clocks
using mtk_clk_fixed_pll_ops are not properly recognized as valid parents
in the CLK_PARENT_APMIXED case.

Fixed PLL clocks are implemented using mtk_clk_fixed_pll_ops instead of
mtk_clk_apmixedsys_ops, but they can also serve as parent clocks in the
APMIXED domain. The parent lookup function needs to check for both
driver ops to properly resolve the parent clock device.

Add mtk_clk_fixed_pll_ops checks alongside mtk_clk_apmixedsys_ops checks
in mtk_find_parent_rate() to restore support for fixed PLL parent clocks.

Also refactor the grandparent lookup code to extract the repeated
dev_get_parent(priv->parent) call into a local variable to keep lines
under 100 characters and pass checkpatch validation.

Fixes: 00d0ff7f81bf ("clk: mediatek: refactor parent rate lookup functions")
Signed-off-by: Sam Shih <sam.shih at mediatek.com>
Signed-off-by: Weijie Gao <weijie.gao at mediatek.com>
---
 drivers/clk/mediatek/clk-mtk.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/clk/mediatek/clk-mtk.c b/drivers/clk/mediatek/clk-mtk.c
index 4adec4457b4..26db60dea7f 100644
--- a/drivers/clk/mediatek/clk-mtk.c
+++ b/drivers/clk/mediatek/clk-mtk.c
@@ -207,20 +207,26 @@ static ulong mtk_clk_find_parent_rate(struct clk *clk, int id,
 static ulong mtk_find_parent_rate(struct mtk_clk_priv *priv, struct clk *clk,
 				  const int parent, u16 flags)
 {
+	struct udevice *grandparent_dev;
 	struct udevice *parent_dev;
 
 	switch (flags & CLK_PARENT_MASK) {
 	case CLK_PARENT_APMIXED:
 		/* APMIXEDSYS can be parent or grandparent. */
-		if (dev_get_driver_ops(clk->dev) == &mtk_clk_apmixedsys_ops)
+		if (dev_get_driver_ops(clk->dev) == &mtk_clk_apmixedsys_ops ||
+		    dev_get_driver_ops(clk->dev) == &mtk_clk_fixed_pll_ops) {
 			parent_dev = clk->dev;
-		else if (dev_get_driver_ops(priv->parent) == &mtk_clk_apmixedsys_ops)
+		} else if (dev_get_driver_ops(priv->parent) == &mtk_clk_apmixedsys_ops ||
+			dev_get_driver_ops(priv->parent) == &mtk_clk_fixed_pll_ops) {
 			parent_dev = priv->parent;
-		else if (dev_get_driver_ops(dev_get_parent(priv->parent)) == &mtk_clk_apmixedsys_ops)
-			parent_dev = dev_get_parent(priv->parent);
-		else
-			return -EINVAL;
-
+		} else {
+			grandparent_dev = dev_get_parent(priv->parent);
+			if (dev_get_driver_ops(grandparent_dev) == &mtk_clk_apmixedsys_ops ||
+			    dev_get_driver_ops(grandparent_dev) == &mtk_clk_fixed_pll_ops)
+				parent_dev = grandparent_dev;
+			else
+				return -EINVAL;
+		}
 		break;
 	case CLK_PARENT_TOPCKGEN:
 		if (dev_get_driver_ops(clk->dev) == &mtk_clk_topckgen_ops)
-- 
2.45.2