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Subject[PATCH v2 1/2] clk: track the orphan status of clocks and their children
Date
While children of orphan clocks are not carried in the orphan-list itself,
they're nevertheless orphans in their own right as they also don't have an
input-rate available. To ease tracking if a clock is an orphan or has an
orphan in its parent path introduce an orphan field into struct clk and
update it and the fields in child-clocks when a clock gets added or removed
from the orphan-list.

Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
drivers/clk/clk.c | 33 ++++++++++++++++++++++++++++++---
1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f85c8e2..a9fa5ab 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -62,6 +62,7 @@ struct clk_core {
struct clk_core *new_parent;
struct clk_core *new_child;
unsigned long flags;
+ bool orphan;
unsigned int enable_count;
unsigned int prepare_count;
unsigned long accuracy;
@@ -1433,18 +1434,40 @@ static int clk_fetch_parent_index(struct clk_core *clk,
return -EINVAL;
}

+/*
+ * Update the orphan status of @clk and all its children.
+ */
+static void clk_update_orphan_status(struct clk_core *clk, int is_orphan)
+{
+ struct clk_core *child;
+
+ clk->orphan = is_orphan;
+
+ hlist_for_each_entry(child, &clk->children, child_node)
+ clk_update_orphan_status(child, is_orphan);
+}
+
static void clk_reparent(struct clk_core *clk, struct clk_core *new_parent)
{
+ bool was_orphan = clk->orphan;
+
hlist_del(&clk->child_node);

if (new_parent) {
+ bool becomes_orphan = new_parent->orphan;
+
/* avoid duplicate POST_RATE_CHANGE notifications */
if (new_parent->new_child == clk)
new_parent->new_child = NULL;

hlist_add_head(&clk->child_node, &new_parent->children);
+
+ if (was_orphan != becomes_orphan)
+ clk_update_orphan_status(clk, becomes_orphan);
} else {
hlist_add_head(&clk->child_node, &clk_orphan_list);
+ if (!was_orphan)
+ clk_update_orphan_status(clk, 1);
}

clk->parent = new_parent;
@@ -2348,13 +2371,17 @@ static int __clk_init(struct device *dev, struct clk *clk_user)
* clocks and re-parent any that are children of the clock currently
* being clk_init'd.
*/
- if (clk->parent)
+ if (clk->parent) {
hlist_add_head(&clk->child_node,
&clk->parent->children);
- else if (clk->flags & CLK_IS_ROOT)
+ clk->orphan = clk->parent->orphan;
+ } else if (clk->flags & CLK_IS_ROOT) {
hlist_add_head(&clk->child_node, &clk_root_list);
- else
+ clk->orphan = 0;
+ } else {
hlist_add_head(&clk->child_node, &clk_orphan_list);
+ clk->orphan = 1;
+ }

/*
* Set clk's accuracy. The preferred method is to use
--
2.1.4



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