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-rw-r--r--include/linux/clk.h68
1 files changed, 63 insertions, 5 deletions
diff --git a/include/linux/clk.h b/include/linux/clk.h
index b9d46fa154b4..b0252726df61 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -3,6 +3,7 @@
*
* Copyright (C) 2004 ARM Limited.
* Written by Deep Blue Solutions Limited.
+ * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -12,18 +13,75 @@
#define __LINUX_CLK_H
#include <linux/kernel.h>
+#include <linux/notifier.h>
struct device;
-/*
- * The base API.
+struct clk;
+
+#ifdef CONFIG_COMMON_CLK
+
+/**
+ * DOC: clk notifier callback types
+ *
+ * PRE_RATE_CHANGE - called immediately before the clk rate is changed,
+ * to indicate that the rate change will proceed. Drivers must
+ * immediately terminate any operations that will be affected by the
+ * rate change. Callbacks may either return NOTIFY_DONE or
+ * NOTIFY_STOP.
+ *
+ * ABORT_RATE_CHANGE: called if the rate change failed for some reason
+ * after PRE_RATE_CHANGE. In this case, all registered notifiers on
+ * the clk will be called with ABORT_RATE_CHANGE. Callbacks must
+ * always return NOTIFY_DONE.
+ *
+ * POST_RATE_CHANGE - called after the clk rate change has successfully
+ * completed. Callbacks must always return NOTIFY_DONE.
+ *
*/
+#define PRE_RATE_CHANGE BIT(0)
+#define POST_RATE_CHANGE BIT(1)
+#define ABORT_RATE_CHANGE BIT(2)
+/**
+ * struct clk_notifier - associate a clk with a notifier
+ * @clk: struct clk * to associate the notifier with
+ * @notifier_head: a blocking_notifier_head for this clk
+ * @node: linked list pointers
+ *
+ * A list of struct clk_notifier is maintained by the notifier code.
+ * An entry is created whenever code registers the first notifier on a
+ * particular @clk. Future notifiers on that @clk are added to the
+ * @notifier_head.
+ */
+struct clk_notifier {
+ struct clk *clk;
+ struct srcu_notifier_head notifier_head;
+ struct list_head node;
+};
-/*
- * struct clk - an machine class defined object / cookie.
+/**
+ * struct clk_notifier_data - rate data to pass to the notifier callback
+ * @clk: struct clk * being changed
+ * @old_rate: previous rate of this clk
+ * @new_rate: new rate of this clk
+ *
+ * For a pre-notifier, old_rate is the clk's rate before this rate
+ * change, and new_rate is what the rate will be in the future. For a
+ * post-notifier, old_rate and new_rate are both set to the clk's
+ * current rate (this was done to optimize the implementation).
*/
-struct clk;
+struct clk_notifier_data {
+ struct clk *clk;
+ unsigned long old_rate;
+ unsigned long new_rate;
+};
+
+int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
+
+int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
+
+#endif /* !CONFIG_COMMON_CLK */
/**
* clk_get - lookup and obtain a reference to a clock producer.