5 files changed, 186 insertions, 0 deletions
diff --git a/drivers/Kconfig b/drivers/Kconfig
index a2b902f4d437..3d93b3a3d630 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -111,4 +111,6 @@ source "drivers/xen/Kconfig"
 source "drivers/staging/Kconfig"
 
 source "drivers/platform/Kconfig"
+
+source "drivers/clk/Kconfig"
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 14cf9077bb2b..4af7d5b124ce 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -114,3 +114,5 @@ obj-$(CONFIG_VLYNQ)		+= vlynq/
 obj-$(CONFIG_STAGING)		+= staging/
 obj-y				+= platform/
 obj-y				+= ieee802154/
+#common clk code
+obj-y				+= clk/
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
new file mode 100644
index 000000000000..4168c8896e16
--- /dev/null
+++ b/drivers/clk/Kconfig
@@ -0,0 +1,4 @@
+
+config CLKDEV_LOOKUP
+	bool
+	select HAVE_CLK
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
new file mode 100644
index 000000000000..07613fa172c9
--- /dev/null
+++ b/drivers/clk/Makefile
@@ -0,0 +1,2 @@
+
+obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
new file mode 100644
index 000000000000..0fc0a79852de
--- /dev/null
+++ b/drivers/clk/clkdev.c
@@ -0,0 +1,176 @@
+/*
+ * drivers/clk/clkdev.c
+ *
+ *  Copyright (C) 2008 Russell King.
+ *
+ * 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
+ * published by the Free Software Foundation.
+ *
+ * Helper for the clk API to assist looking up a struct clk.
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/mutex.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+
+static LIST_HEAD(clocks);
+static DEFINE_MUTEX(clocks_mutex);
+
+/*
+ * Find the correct struct clk for the device and connection ID.
+ * We do slightly fuzzy matching here:
+ *  An entry with a NULL ID is assumed to be a wildcard.
+ *  If an entry has a device ID, it must match
+ *  If an entry has a connection ID, it must match
+ * Then we take the most specific entry - with the following
+ * order of precedence: dev+con > dev only > con only.
+ */
+static struct clk *clk_find(const char *dev_id, const char *con_id)
+{
+	struct clk_lookup *p;
+	struct clk *clk = NULL;
+	int match, best = 0;
+
+	list_for_each_entry(p, &clocks, node) {
+		match = 0;
+		if (p->dev_id) {
+			if (!dev_id || strcmp(p->dev_id, dev_id))
+				continue;
+			match += 2;
+		}
+		if (p->con_id) {
+			if (!con_id || strcmp(p->con_id, con_id))
+				continue;
+			match += 1;
+		}
+
+		if (match > best) {
+			clk = p->clk;
+			if (match != 3)
+				best = match;
+			else
+				break;
+		}
+	}
+	return clk;
+}
+
+struct clk *clk_get_sys(const char *dev_id, const char *con_id)
+{
+	struct clk *clk;
+
+	mutex_lock(&clocks_mutex);
+	clk = clk_find(dev_id, con_id);
+	if (clk && !__clk_get(clk))
+		clk = NULL;
+	mutex_unlock(&clocks_mutex);
+
+	return clk ? clk : ERR_PTR(-ENOENT);
+}
+EXPORT_SYMBOL(clk_get_sys);
+
+struct clk *clk_get(struct device *dev, const char *con_id)
+{
+	const char *dev_id = dev ? dev_name(dev) : NULL;
+
+	return clk_get_sys(dev_id, con_id);
+}
+EXPORT_SYMBOL(clk_get);
+
+void clk_put(struct clk *clk)
+{
+	__clk_put(clk);
+}
+EXPORT_SYMBOL(clk_put);
+
+void clkdev_add(struct clk_lookup *cl)
+{
+	mutex_lock(&clocks_mutex);
+	list_add_tail(&cl->node, &clocks);
+	mutex_unlock(&clocks_mutex);
+}
+EXPORT_SYMBOL(clkdev_add);
+
+void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
+{
+	mutex_lock(&clocks_mutex);
+	while (num--) {
+		list_add_tail(&cl->node, &clocks);
+		cl++;
+	}
+	mutex_unlock(&clocks_mutex);
+}
+
+#define MAX_DEV_ID	20
+#define MAX_CON_ID	16
+
+struct clk_lookup_alloc {
+	struct clk_lookup cl;
+	char	dev_id[MAX_DEV_ID];
+	char	con_id[MAX_CON_ID];
+};
+
+struct clk_lookup * __init_refok
+clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
+{
+	struct clk_lookup_alloc *cla;
+
+	cla = __clkdev_alloc(sizeof(*cla));
+	if (!cla)
+		return NULL;
+
+	cla->cl.clk = clk;
+	if (con_id) {
+		strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
+		cla->cl.con_id = cla->con_id;
+	}
+
+	if (dev_fmt) {
+		va_list ap;
+
+		va_start(ap, dev_fmt);
+		vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
+		cla->cl.dev_id = cla->dev_id;
+		va_end(ap);
+	}
+
+	return &cla->cl;
+}
+EXPORT_SYMBOL(clkdev_alloc);
+
+int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
+	struct device *dev)
+{
+	struct clk *r = clk_get(dev, id);
+	struct clk_lookup *l;
+
+	if (IS_ERR(r))
+		return PTR_ERR(r);
+
+	l = clkdev_alloc(r, alias, alias_dev_name);
+	clk_put(r);
+	if (!l)
+		return -ENODEV;
+	clkdev_add(l);
+	return 0;
+}
+EXPORT_SYMBOL(clk_add_alias);
+
+/*
+ * clkdev_drop - remove a clock dynamically allocated
+ */
+void clkdev_drop(struct clk_lookup *cl)
+{
+	mutex_lock(&clocks_mutex);
+	list_del(&cl->node);
+	mutex_unlock(&clocks_mutex);
+	kfree(cl);
+}
+EXPORT_SYMBOL(clkdev_drop);