[PATCH v6 3/4] clk: keystone: sci-clk: add restore_context() operation

Thomas Richard (TI)
2026-04-27T12:22:24Z

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() and recalc_rate() operations. 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().

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Kendall Willis <k-willis@ti.com>
Signed-off-by: Thomas Richard (TI) <thomas.richard@bootlin.com>
---
drivers/clk/keystone/sci-clk.c | 44 ++++++++++++++++++++++++++++++++++--------
1 file changed, 36 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c
index 9d5071223f4c..b090edf5f82e 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)
@@ -150,6 +154,8 @@ static unsigned long sci_clk_recalc_rate(struct clk_hw *hw,
return 0;
}

+ clk->rate = freq;
+
return freq;
}

@@ -210,10 +216,15 @@ 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;

- return clk->provider->ops->set_freq(clk->provider->sci, clk->dev_id,
- clk->clk_id, rate / 10 * 9, rate,
- rate / 10 * 11);
+ ret = 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 +248,9 @@ 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 +263,28 @@ 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);
+
+ if (clk->num_parents > 1)
+ 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 +296,7 @@ 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,
};

/**

--
2.53.0