[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>

3 files changed, 132 insertions, 0 deletions

diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig
index 86b5e69..a2cd9be 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 325e4b6..7cb7961 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 0000000..17a17b4
--- /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);