[ARM] clkdev: add generic clkdev infrastructure

Add some generic infrastructure to assist looking up struct clks
for the ARM architecture.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

4 files changed, 162 insertions, 0 deletions

diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig
index 86b5e6982660..a2cd9beaf37d 100644
--- a/arch/arm/common/Kconfig
+++ b/arch/arm/common/Kconfig
@@ -33,3 +33,6 @@ config SHARPSL_PM
 
 config SHARP_SCOOP
         bool
+
+config COMMON_CLKDEV
+        bool
diff --git a/arch/arm/common/Makefile b/arch/arm/common/Makefile
index 325e4b6a6afb..7cb7961d81cb 100644
--- a/arch/arm/common/Makefile
+++ b/arch/arm/common/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_SHARP_SCOOP)	+= scoop.o
 obj-$(CONFIG_ARCH_IXP2000)      += uengine.o
 obj-$(CONFIG_ARCH_IXP23XX)      += uengine.o
 obj-$(CONFIG_PCI_HOST_ITE8152)  += it8152.o
+obj-$(CONFIG_COMMON_CLKDEV)     += clkdev.o
diff --git a/arch/arm/common/clkdev.c b/arch/arm/common/clkdev.c
new file mode 100644
index 000000000000..17a17b49a45b
--- /dev/null
+++ b/arch/arm/common/clkdev.c
@@ -0,0 +1,128 @@
+/*
+ *  arch/arm/common/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 <asm/clkdev.h>
+#include <mach/clkdev.h>
+
+static LIST_HEAD(clocks);
+static DEFINE_MUTEX(clocks_mutex);
+
+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) {
+                if ((p->dev_id && !dev_id) || (p->con_id && !con_id))
+                        continue;
+                match = 0;
+                if (p->dev_id)
+                        match += 2 * (strcmp(p->dev_id, dev_id) == 0);
+                if (p->con_id)
+                        match += 1 * (strcmp(p->con_id, con_id) == 0);
+                if (match == 0)
+                        continue;
+
+                if (match > best) {
+                        clk = p->clk;
+                        best = match;
+                }
+        }
+        return clk;
+}
+
+struct clk *clk_get(struct device *dev, const char *con_id)
+{
+        const char *dev_id = dev ? dev_name(dev) : NULL;
+        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);
+
+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);
+
+#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 *clkdev_alloc(struct clk *clk, const char *con_id,
+        const char *dev_fmt, ...)
+{
+        struct clk_lookup_alloc *cla;
+
+        cla = kzalloc(sizeof(*cla), GFP_KERNEL);
+        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);
+
+/*
+ * 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);
diff --git a/arch/arm/include/asm/clkdev.h b/arch/arm/include/asm/clkdev.h
new file mode 100644
index 000000000000..b6ec7c627b39
--- /dev/null
+++ b/arch/arm/include/asm/clkdev.h
@@ -0,0 +1,30 @@
+/*
+ *  arch/arm/include/asm/clkdev.h
+ *
+ *  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.
+ */
+#ifndef __ASM_CLKDEV_H
+#define __ASM_CLKDEV_H
+
+struct clk;
+
+struct clk_lookup {
+        struct list_head        node;
+        const char              *dev_id;
+        const char              *con_id;
+        struct clk              *clk;
+};
+
+struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
+        const char *dev_fmt, ...);
+
+void clkdev_add(struct clk_lookup *cl);
+void clkdev_drop(struct clk_lookup *cl);
+
+#endif