ARM: Add the clock framework for Telechips TCC8xxx processors.

This adds definitions and low-level functions to handle clocks in
TCC8xxx processors.

Signed-off-by: "Hans J. Koch" <hjk@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 179 insertions, 0 deletions

diff --git a/arch/arm/plat-tcc/clock.c b/arch/arm/plat-tcc/clock.c
new file mode 100644
index 0000000..f3ced10
--- /dev/null
+++ b/arch/arm/plat-tcc/clock.c
@@ -0,0 +1,179 @@
+/*
+ * Clock framework for Telechips SoCs
+ * Based on arch/arm/plat-mxc/clock.c
+ *
+ * Copyright (C) 2004 - 2005 Nokia corporation
+ * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
+ * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
+ * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
+ * Copyright 2010 Hans J. Koch, hjk@linutronix.de
+ *
+ * Licensed under the terms of the GPL v2.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+
+#include <mach/clock.h>
+#include <mach/hardware.h>
+
+static DEFINE_MUTEX(clocks_mutex);
+
+/*-------------------------------------------------------------------------
+ * Standard clock functions defined in include/linux/clk.h
+ *-------------------------------------------------------------------------*/
+
+static void __clk_disable(struct clk *clk)
+{
+	BUG_ON(clk->refcount == 0);
+
+	if (!(--clk->refcount) && clk->disable) {
+		/* Unconditionally disable the clock in hardware */
+		clk->disable(clk);
+		/* recursively disable parents */
+		if (clk->parent)
+			__clk_disable(clk->parent);
+	}
+}
+
+static int __clk_enable(struct clk *clk)
+{
+	int ret = 0;
+
+	if (clk->refcount++ == 0 && clk->enable) {
+		if (clk->parent)
+			ret = __clk_enable(clk->parent);
+		if (ret)
+			return ret;
+		else
+			return clk->enable(clk);
+	}
+
+	return 0;
+}
+
+/* This function increments the reference count on the clock and enables the
+ * clock if not already enabled. The parent clock tree is recursively enabled
+ */
+int clk_enable(struct clk *clk)
+{
+	int ret = 0;
+
+	if (!clk)
+		return -EINVAL;
+
+	mutex_lock(&clocks_mutex);
+	ret = __clk_enable(clk);
+	mutex_unlock(&clocks_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_enable);
+
+/* This function decrements the reference count on the clock and disables
+ * the clock when reference count is 0. The parent clock tree is
+ * recursively disabled
+ */
+void clk_disable(struct clk *clk)
+{
+	if (!clk)
+		return;
+
+	mutex_lock(&clocks_mutex);
+	__clk_disable(clk);
+	mutex_unlock(&clocks_mutex);
+}
+EXPORT_SYMBOL_GPL(clk_disable);
+
+/* Retrieve the *current* clock rate. If the clock itself
+ * does not provide a special calculation routine, ask
+ * its parent and so on, until one is able to return
+ * a valid clock rate
+ */
+unsigned long clk_get_rate(struct clk *clk)
+{
+	if (!clk)
+		return 0UL;
+
+	if (clk->get_rate)
+		return clk->get_rate(clk);
+
+	return clk_get_rate(clk->parent);
+}
+EXPORT_SYMBOL_GPL(clk_get_rate);
+
+/* Round the requested clock rate to the nearest supported
+ * rate that is less than or equal to the requested rate.
+ * This is dependent on the clock's current parent.
+ */
+long clk_round_rate(struct clk *clk, unsigned long rate)
+{
+	if (!clk)
+		return 0;
+	if (!clk->round_rate)
+		return 0;
+
+	return clk->round_rate(clk, rate);
+}
+EXPORT_SYMBOL_GPL(clk_round_rate);
+
+/* Set the clock to the requested clock rate. The rate must
+ * match a supported rate exactly based on what clk_round_rate returns
+ */
+int clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	int ret = -EINVAL;
+
+	if (!clk)
+		return ret;
+	if (!clk->set_rate || !rate)
+		return ret;
+
+	mutex_lock(&clocks_mutex);
+	ret = clk->set_rate(clk, rate);
+	mutex_unlock(&clocks_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_set_rate);
+
+/* Set the clock's parent to another clock source */
+int clk_set_parent(struct clk *clk, struct clk *parent)
+{
+	struct clk *old;
+	int ret = -EINVAL;
+
+	if (!clk)
+		return ret;
+	if (!clk->set_parent || !parent)
+		return ret;
+
+	mutex_lock(&clocks_mutex);
+	old = clk->parent;
+	if (clk->refcount)
+		__clk_enable(parent);
+	ret = clk->set_parent(clk, parent);
+	if (ret)
+		old = parent;
+	if (clk->refcount)
+		__clk_disable(old);
+	mutex_unlock(&clocks_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(clk_set_parent);
+
+/* Retrieve the clock's parent clock source */
+struct clk *clk_get_parent(struct clk *clk)
+{
+	if (!clk)
+		return NULL;
+
+	return clk->parent;
+}
+EXPORT_SYMBOL_GPL(clk_get_parent);