linux-kernel - [PATCH RFC v2 3/4] clk: keystone: sci-clk: add restore

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Message-Id: <20251127-ti-sci-jacinto-s2r-restore-irq-v2-3-a487fa3ff221@bootlin.com>
Date: Thu, 27 Nov 2025 09:38:57 +0100
From: "Thomas Richard (TI.com)" <thomas.richard@...tlin.com>
To: Nishanth Menon <nm@...com>, Tero Kristo <kristo@...nel.org>, 
 Santosh Shilimkar <ssantosh@...nel.org>, 
 Michael Turquette <mturquette@...libre.com>, 
 Stephen Boyd <sboyd@...nel.org>
Cc: Gregory CLEMENT <gregory.clement@...tlin.com>, 
 richard.genoud@...tlin.com, Udit Kumar <u-kumar1@...com>, 
 Prasanth Mantena <p-mantena@...com>, Abhash Kumar <a-kumar2@...com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 linux-clk@...r.kernel.org, 
 "Thomas Richard (TI.com)" <thomas.richard@...tlin.com>
Subject: [PATCH RFC v2 3/4] clk: keystone: sci-clk: add restore_context()
 operation

Implement the restore_context() operation to restore the clock parent
state. The parent index is saved in sci_clk struct during set_parent().
During clock registration, the core retrieves each clock’s parent using
get_parent() operation to ensure the internal clock tree reflects the
actual hardware state, including any configurations made by the
bootloader. So we also save the parent index in get_parent().

Signed-off-by: Thomas Richard (TI.com) <thomas.richard@...tlin.com>
---
 drivers/clk/keystone/sci-clk.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c
index a4b42811de55d..1e5dd01484d1c 100644
--- a/drivers/clk/keystone/sci-clk.c
+++ b/drivers/clk/keystone/sci-clk.c
@@ -47,6 +47,7 @@ struct sci_clk_provider {
  * @node:	 Link for handling clocks probed via DT
  * @cached_req:	 Cached requested freq for determine rate calls
  * @cached_res:	 Cached result freq for determine rate calls
+ * @parent_id:	 Parent index for this clock
  */
 struct sci_clk {
 	struct clk_hw hw;
@@ -58,6 +59,7 @@ struct sci_clk {
 	struct list_head node;
 	unsigned long cached_req;
 	unsigned long cached_res;
+	u8 parent_id;
 };
 
 #define to_sci_clk(_hw) container_of(_hw, struct sci_clk, hw)
@@ -237,9 +239,9 @@ static u8 sci_clk_get_parent(struct clk_hw *hw)
 		return 0;
 	}
 
-	parent_id = parent_id - clk->clk_id - 1;
+	clk->parent_id = (u8)(parent_id - clk->clk_id - 1);
 
-	return (u8)parent_id;
+	return clk->parent_id;
 }
 
 /**
@@ -252,12 +254,24 @@ static u8 sci_clk_get_parent(struct clk_hw *hw)
 static int sci_clk_set_parent(struct clk_hw *hw, u8 index)
 {
 	struct sci_clk *clk = to_sci_clk(hw);
+	int ret;
 
 	clk->cached_req = 0;
 
-	return clk->provider->ops->set_parent(clk->provider->sci, clk->dev_id,
-					      clk->clk_id,
-					      index + 1 + clk->clk_id);
+	ret = clk->provider->ops->set_parent(clk->provider->sci, clk->dev_id,
+					     clk->clk_id,
+					     index + 1 + clk->clk_id);
+	if (!ret)
+		clk->parent_id = index;
+
+	return ret;
+}
+
+static void sci_clk_restore_context(struct clk_hw *hw)
+{
+	struct sci_clk *clk = to_sci_clk(hw);
+
+	sci_clk_set_parent(hw, clk->parent_id);
 }
 
 static const struct clk_ops sci_clk_ops = {
@@ -269,6 +283,7 @@ static const struct clk_ops sci_clk_ops = {
 	.set_rate = sci_clk_set_rate,
 	.get_parent = sci_clk_get_parent,
 	.set_parent = sci_clk_set_parent,
+	.restore_context = sci_clk_restore_context,
 };
 
 /**

-- 
2.51.0