linux-kernel - [PATCH v3 3/4] clk: keystone: sci-clk: add restore

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Message-Id: <20251205-ti-sci-jacinto-s2r-restore-irq-v3-3-d06963974ad4@bootlin.com>
Date: Fri, 05 Dec 2025 15:28:25 +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 v3 3/4] clk: keystone: sci-clk: add restore_context()
 operation

Implement the restore_context() operation to restore the clock rate and the
clock parent state. The clock rate is saved in sci_clk struct during
set_rate() operation. The parent index is saved in sci_clk struct during
set_parent() operation. 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 | 42 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c
index 9d5071223f4cb..428050a05de31 100644
--- a/drivers/clk/keystone/sci-clk.c
+++ b/drivers/clk/keystone/sci-clk.c
@@ -47,6 +47,8 @@ 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
+ * @rate:	 Clock rate
  */
 struct sci_clk {
 	struct clk_hw hw;
@@ -58,6 +60,8 @@ struct sci_clk {
 	struct list_head node;
 	unsigned long cached_req;
 	unsigned long cached_res;
+	u8 parent_id;
+	unsigned long rate;
 };
 
 #define to_sci_clk(_hw) container_of(_hw, struct sci_clk, hw)
@@ -210,10 +214,16 @@ static int sci_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 			    unsigned long parent_rate)
 {
 	struct sci_clk *clk = to_sci_clk(hw);
+	int ret;
+
+	ret = clk->provider->ops->set_freq(clk->provider->sci, clk->dev_id,
+					   clk->clk_id, rate / 10 * 9, rate,
+					   rate / 10 * 11);
 
-	return clk->provider->ops->set_freq(clk->provider->sci, clk->dev_id,
-					    clk->clk_id, rate / 10 * 9, rate,
-					    rate / 10 * 11);
+	if (!ret)
+		clk->rate = rate;
+
+	return ret;
 }
 
 /**
@@ -237,9 +247,9 @@ 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 +262,27 @@ 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);
+
+	if (clk->rate)
+		sci_clk_set_rate(hw, clk->rate, 0);
 }
 
 static const struct clk_ops sci_clk_ops = {
@@ -269,6 +294,7 @@ 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