3 files changed, 182 insertions, 0 deletions

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);