ARM: 6483/1: arm & sh: factorised duplicated clkdev.c

[mv-sheeva.git] / drivers / clk / clkdev.c

diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
new file mode 100644 (file)
index 0000000..0fc0a79
--- /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);