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/*
* 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);
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