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Subject[RFC 1/4] clk: Add CLK_GET_PARENT_NOCACHE flag
Date
This can be used by the clocks that have their parents changed from EL3.
This way the clk_get_parent will read the value from register instead of
using the value stored in the core framework.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Suggested-by: Peng Fan <peng.fan@nxp.com>
---
drivers/clk/clk.c | 31 +++++++++++++++++--------------
include/linux/clk-provider.h | 1 +
2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 90d2373..474315d 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2401,6 +2401,16 @@ int clk_set_max_rate(struct clk *clk, unsigned long rate)
}
EXPORT_SYMBOL_GPL(clk_set_max_rate);

+static struct clk_core *__clk_get_parent(struct clk_core *core)
+{
+ u8 index = 0;
+
+ if (core->num_parents > 1 && core->ops->get_parent)
+ index = core->ops->get_parent(core->hw);
+
+ return clk_core_get_parent_by_index(core, index);
+}
+
/**
* clk_get_parent - return the parent of a clk
* @clk: the clk whose parent gets returned
@@ -2415,24 +2425,17 @@ struct clk *clk_get_parent(struct clk *clk)
return NULL;

clk_prepare_lock();
- /* TODO: Create a per-user clk and change callers to call clk_put */
- parent = !clk->core->parent ? NULL : clk->core->parent->hw->clk;
+ if (clk->core && (clk->core->flags & CLK_GET_PARENT_NOCACHE))
+ parent = __clk_get_parent(clk->core)->hw->clk;
+ else
+ /* TODO: Create a per-user clk and change callers to call clk_put */
+ parent = !clk->core->parent ? NULL : clk->core->parent->hw->clk;
clk_prepare_unlock();

return parent;
}
EXPORT_SYMBOL_GPL(clk_get_parent);

-static struct clk_core *__clk_init_parent(struct clk_core *core)
-{
- u8 index = 0;
-
- if (core->num_parents > 1 && core->ops->get_parent)
- index = core->ops->get_parent(core->hw);
-
- return clk_core_get_parent_by_index(core, index);
-}
-
static void clk_core_reparent(struct clk_core *core,
struct clk_core *new_parent)
{
@@ -3353,7 +3356,7 @@ static void clk_core_reparent_orphans_nolock(void)
* parent.
*/
hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
- struct clk_core *parent = __clk_init_parent(orphan);
+ struct clk_core *parent = __clk_get_parent(orphan);

/*
* We need to use __clk_set_parent_before() and _after() to
@@ -3454,7 +3457,7 @@ static int __clk_core_init(struct clk_core *core)
goto out;
}

- parent = core->parent = __clk_init_parent(core);
+ parent = core->parent = __clk_get_parent(core);

/*
* Populate core->parent if parent has already been clk_core_init'd. If
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index d98e41f..94a78b3 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -33,6 +33,7 @@
/* duty cycle call may be forwarded to the parent clock */
#define CLK_DUTY_CYCLE_PARENT BIT(13)
#define CLK_SET_PARENT_NOCACHE BIT(14) /* do not use the cached clk parent */
+#define CLK_GET_PARENT_NOCACHE BIT(15) /* read the parent from reg */

struct clk;
struct clk_hw;
--
2.7.4
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