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path: root/drivers/clk/clk.c
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Diffstat (limited to 'drivers/clk/clk.c')
-rw-r--r--drivers/clk/clk.c121
1 files changed, 118 insertions, 3 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index baa2f66a7d19..da7b33e4c5a2 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -345,6 +345,21 @@ out:
return ret;
}
+ /**
+ * clk_debug_unregister - remove a clk node from the debugfs clk tree
+ * @clk: the clk being removed from the debugfs clk tree
+ *
+ * Dynamically removes a clk and all it's children clk nodes from the
+ * debugfs clk tree if clk->dentry points to debugfs created by
+ * clk_debug_register in __clk_init.
+ *
+ * Caller must hold prepare_lock.
+ */
+static void clk_debug_unregister(struct clk *clk)
+{
+ debugfs_remove_recursive(clk->dentry);
+}
+
/**
* clk_debug_reparent - reparent clk node in the debugfs clk tree
* @clk: the clk being reparented
@@ -435,6 +450,9 @@ static inline int clk_debug_register(struct clk *clk) { return 0; }
static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
{
}
+static inline void clk_debug_unregister(struct clk *clk)
+{
+}
#endif
/* caller must hold prepare_lock */
@@ -1778,6 +1796,7 @@ int __clk_init(struct device *dev, struct clk *clk)
clk_debug_register(clk);
+ kref_init(&clk->ref);
out:
clk_prepare_unlock();
@@ -1913,13 +1932,104 @@ fail_out:
}
EXPORT_SYMBOL_GPL(clk_register);
+/*
+ * Free memory allocated for a clock.
+ * Caller must hold prepare_lock.
+ */
+static void __clk_release(struct kref *ref)
+{
+ struct clk *clk = container_of(ref, struct clk, ref);
+ int i = clk->num_parents;
+
+ kfree(clk->parents);
+ while (--i >= 0)
+ kfree(clk->parent_names[i]);
+
+ kfree(clk->parent_names);
+ kfree(clk->name);
+ kfree(clk);
+}
+
+/*
+ * Empty clk_ops for unregistered clocks. These are used temporarily
+ * after clk_unregister() was called on a clock and until last clock
+ * consumer calls clk_put() and the struct clk object is freed.
+ */
+static int clk_nodrv_prepare_enable(struct clk_hw *hw)
+{
+ return -ENXIO;
+}
+
+static void clk_nodrv_disable_unprepare(struct clk_hw *hw)
+{
+ WARN_ON_ONCE(1);
+}
+
+static int clk_nodrv_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ return -ENXIO;
+}
+
+static int clk_nodrv_set_parent(struct clk_hw *hw, u8 index)
+{
+ return -ENXIO;
+}
+
+static const struct clk_ops clk_nodrv_ops = {
+ .enable = clk_nodrv_prepare_enable,
+ .disable = clk_nodrv_disable_unprepare,
+ .prepare = clk_nodrv_prepare_enable,
+ .unprepare = clk_nodrv_disable_unprepare,
+ .set_rate = clk_nodrv_set_rate,
+ .set_parent = clk_nodrv_set_parent,
+};
+
/**
* clk_unregister - unregister a currently registered clock
* @clk: clock to unregister
- *
- * Currently unimplemented.
*/
-void clk_unregister(struct clk *clk) {}
+void clk_unregister(struct clk *clk)
+{
+ unsigned long flags;
+
+ if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
+ return;
+
+ clk_prepare_lock();
+
+ if (clk->ops == &clk_nodrv_ops) {
+ pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
+ goto out;
+ }
+ /*
+ * Assign empty clock ops for consumers that might still hold
+ * a reference to this clock.
+ */
+ flags = clk_enable_lock();
+ clk->ops = &clk_nodrv_ops;
+ clk_enable_unlock(flags);
+
+ if (!hlist_empty(&clk->children)) {
+ struct clk *child;
+
+ /* Reparent all children to the orphan list. */
+ hlist_for_each_entry(child, &clk->children, child_node)
+ clk_set_parent(child, NULL);
+ }
+
+ clk_debug_unregister(clk);
+
+ hlist_del_init(&clk->child_node);
+
+ if (clk->prepare_count)
+ pr_warn("%s: unregistering prepared clock: %s\n",
+ __func__, clk->name);
+
+ kref_put(&clk->ref, __clk_release);
+out:
+ clk_prepare_unlock();
+}
EXPORT_SYMBOL_GPL(clk_unregister);
static void devm_clk_release(struct device *dev, void *res)
@@ -1987,6 +2097,7 @@ int __clk_get(struct clk *clk)
if (clk && !try_module_get(clk->owner))
return 0;
+ kref_get(&clk->ref);
return 1;
}
@@ -1995,6 +2106,10 @@ void __clk_put(struct clk *clk)
if (WARN_ON_ONCE(IS_ERR(clk)))
return;
+ clk_prepare_lock();
+ kref_put(&clk->ref, __clk_release);
+ clk_prepare_unlock();
+
if (clk)
module_put(clk->owner);
}