ns9xxx: add clock api

Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>

arch/arm/mach-ns9xxx/Makefile

@@ -1,4 +1,4 @@
-obj-y := irq.o generic.o gpio.o
+obj-y := clock.o generic.o gpio.o irq.o
 
 obj-$(CONFIG_MACH_CC9P9360DEV) += mach-cc9p9360dev.o
 obj-$(CONFIG_MACH_CC9P9360JS) += mach-cc9p9360js.o

arch/arm/mach-ns9xxx/clock.c

@@ -0,0 +1,215 @@
+/*
+ * arch/arm/mach-ns9xxx/clock.c
+ *
+ * Copyright (C) 2007 by Digi International Inc.
+ * All rights reserved.
+ *
+ * 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.
+ */
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/clk.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+
+#include <asm/semaphore.h>
+#include "clock.h"
+
+static LIST_HEAD(clocks);
+static DEFINE_SPINLOCK(clk_lock);
+
+struct clk *clk_get(struct device *dev, const char *id)
+{
+	struct clk *p, *ret = NULL, *retgen = NULL;
+	unsigned long flags;
+	int idno;
+
+	if (dev == NULL || dev->bus != &platform_bus_type)
+		idno = -1;
+	else
+		idno = to_platform_device(dev)->id;
+
+	spin_lock_irqsave(&clk_lock, flags);
+	list_for_each_entry(p, &clocks, node) {
+		if (strcmp(id, p->name) == 0) {
+			if (p->id == idno) {
+				if (!try_module_get(p->owner))
+					continue;
+				ret = p;
+				break;
+			} else if (p->id == -1)
+				/* remember match with id == -1 in case there is
+				 * no clock for idno */
+				retgen = p;
+		}
+	}
+
+	if (!ret && retgen && try_module_get(retgen->owner))
+		ret = retgen;
+
+	if (ret)
+		++ret->refcount;
+
+	spin_unlock_irqrestore(&clk_lock, flags);
+
+	return ret ? ret : ERR_PTR(-ENOENT);
+}
+EXPORT_SYMBOL(clk_get);
+
+void clk_put(struct clk *clk)
+{
+	module_put(clk->owner);
+	--clk->refcount;
+}
+EXPORT_SYMBOL(clk_put);
+
+static int clk_enable_unlocked(struct clk *clk)
+{
+	int ret = 0;
+	if (clk->parent) {
+		ret = clk_enable_unlocked(clk->parent);
+		if (ret)
+			return ret;
+	}
+
+	if (clk->usage++ == 0 && clk->endisable)
+		ret = clk->endisable(clk, 1);
+
+	return ret;
+}
+
+int clk_enable(struct clk *clk)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&clk_lock, flags);
+
+	ret = clk_enable_unlocked(clk);
+
+	spin_unlock_irqrestore(&clk_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(clk_enable);
+
+static void clk_disable_unlocked(struct clk *clk)
+{
+	if (--clk->usage == 0 && clk->endisable)
+		clk->endisable(clk, 0);
+
+	if (clk->parent)
+		clk_disable_unlocked(clk->parent);
+}
+
+void clk_disable(struct clk *clk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&clk_lock, flags);
+
+	clk_disable_unlocked(clk);
+
+	spin_unlock_irqrestore(&clk_lock, flags);
+}
+EXPORT_SYMBOL(clk_disable);
+
+unsigned long clk_get_rate(struct clk *clk)
+{
+	if (clk->get_rate)
+		return clk->get_rate(clk);
+
+	if (clk->rate)
+		return clk->rate;
+
+	if (clk->parent)
+		return clk_get_rate(clk->parent);
+
+	return 0;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
+int clk_register(struct clk *clk)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&clk_lock, flags);
+
+	list_add(&clk->node, &clocks);
+
+	if (clk->parent)
+		++clk->parent->refcount;
+
+	spin_unlock_irqrestore(&clk_lock, flags);
+
+	return 0;
+}
+
+int clk_unregister(struct clk *clk)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&clk_lock, flags);
+
+	if (clk->usage || clk->refcount)
+		ret = -EBUSY;
+	else
+		list_del(&clk->node);
+
+	if (clk->parent)
+		--clk->parent->refcount;
+
+	spin_unlock_irqrestore(&clk_lock, flags);
+
+	return ret;
+}
+
+#if defined CONFIG_DEBUG_FS
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+static int clk_debugfs_show(struct seq_file *s, void *null)
+{
+	unsigned long flags;
+	struct clk *p;
+
+	spin_lock_irqsave(&clk_lock, flags);
+
+	list_for_each_entry(p, &clocks, node)
+		seq_printf(s, "%s.%d: usage=%lu refcount=%lu rate=%lu\n",
+				p->name, p->id, p->usage, p->refcount,
+				p->usage ? clk_get_rate(p) : 0);
+
+	spin_unlock_irqrestore(&clk_lock, flags);
+
+	return 0;
+}
+
+static int clk_debugfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, clk_debugfs_show, NULL);
+}
+
+static struct file_operations clk_debugfs_operations = {
+	.open = clk_debugfs_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int __init clk_debugfs_init(void)
+{
+	struct dentry *dentry;
+
+	dentry = debugfs_create_file("clk", S_IFREG | S_IRUGO, NULL, NULL,
+			&clk_debugfs_operations);
+	return IS_ERR(dentry) ? PTR_ERR(dentry) : 0;
+}
+subsys_initcall(clk_debugfs_init);
+
+#endif /* if defined CONFIG_DEBUG_FS */

arch/arm/mach-ns9xxx/clock.h

@@ -0,0 +1,35 @@
+/*
+ * arch/arm/mach-ns9xxx/clock.h
+ *
+ * Copyright (C) 2007 by Digi International Inc.
+ * All rights reserved.
+ *
+ * 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.
+ */
+#ifndef __NS9XXX_CLOCK_H
+#define __NS9XXX_CLOCK_H
+
+#include <linux/list.h>
+
+struct clk {
+	struct module *owner;
+	const char *name;
+	int id;
+
+	struct clk *parent;
+
+	unsigned long rate;
+	int (*endisable)(struct clk *, int enable);
+	unsigned long (*get_rate)(struct clk *);
+
+	struct list_head node;
+	unsigned long refcount;
+	unsigned long usage;
+};
+
+int clk_register(struct clk *clk);
+int clk_unregister(struct clk *clk);
+
+#endif /* ifndef __NS9XXX_CLOCK_H */