[PATCH v10 6/9] clk: Warn of unbalanced clk_prepare() calls

[Tomeu Vizoso]

The warning will display the clock user that is trying to unprepare the clock,
and the location of the last unprepare call.

Signed-off-by: Tomeu Vizoso <tomeu.viz...@collabora.com>

---

v8: * Patch added
---
 drivers/clk/clk.c           | 22 ++++++++++++++++++++--
 include/linux/clk-private.h |  3 +++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 3a961c6..3018f37 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -834,7 +834,17 @@ void clk_unprepare(struct clk *clk_user)
        if (IS_ERR_OR_NULL(clk_user))
                return;
 
-       clk_provider_unprepare(clk_to_clk_core(clk_user));
+       clk_prepare_lock();
+       if (!WARN(clk_user->prepare_count == 0,
+                 "incorrect unprepare clk dev %s con %s last caller of 
unprepare %pF\n",
+                 clk_user->dev_id, clk_user->con_id, 
clk_user->last_unprepare)) {
+
+               clk_user->last_unprepare = __builtin_return_address(0);
+               clk_user->prepare_count--;
+
+               __clk_unprepare(clk_to_clk_core(clk_user));
+       }
+       clk_prepare_unlock();
 }
 EXPORT_SYMBOL_GPL(clk_unprepare);
 
@@ -890,10 +900,18 @@ EXPORT_SYMBOL_GPL(clk_provider_prepare);
  */
 int clk_prepare(struct clk *clk_user)
 {
+       int ret;
+
        if (!clk_user)
                return 0;
 
-       return clk_provider_prepare(clk_to_clk_core(clk_user));
+       clk_prepare_lock();
+       ret = __clk_prepare(clk_to_clk_core(clk_user));
+       if (!ret)
+               clk_user->prepare_count++;
+       clk_prepare_unlock();
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(clk_prepare);
 
diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index 8126046..cf93bde 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -64,6 +64,9 @@ struct clk {
        unsigned int    enable_count;
        void            *last_disable;
 
+       unsigned int    prepare_count;
+       void            *last_unprepare;
+
        unsigned long   floor_constraint;
        unsigned long   ceiling_constraint;
        struct hlist_node child_node;
-- 
1.9.3

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