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@bootlin.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
On 11/27/2025 2:08 PM, Thomas Richard (TI.com) wrote:
> 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@bootlin.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;
you may need to restore rate as well
> };
>
> #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);
You should restore, if this is BOARD_CFG managed
> }
>
> 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,
> };
>
> /**
>
Hi Udit,
On 12/3/25 8:50 AM, Kumar, Udit wrote:
>
> On 11/27/2025 2:08 PM, Thomas Richard (TI.com) wrote:
>> 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@bootlin.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;
>
> you may need to restore rate as well
will do in v3.
>
>
>> };
>> #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);
>
> You should restore, if this is BOARD_CFG managed
restore_context() operation is called by clk_restore_context() for each
registered clock. And we call clk_restore_context() from ti_sci driver
only for BOARDCFG_MANAGED mode.
sci-clk driver cannot decide if clock context shall be restored or not.
Decision shall come from ti_sci as it knows the lpm mode.
Best Regards,
Thomas
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