You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
198 lines
4.8 KiB
198 lines
4.8 KiB
/*
|
|
* Based on arch/arm/plat-omap/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
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
|
|
* MA 02110-1301, USA.
|
|
*/
|
|
|
|
/* #define DEBUG */
|
|
|
|
#include <linux/clk.h>
|
|
#include <linux/err.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/init.h>
|
|
#include <linux/io.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/list.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/semaphore.h>
|
|
#include <linux/string.h>
|
|
|
|
#include <mach/clock.h>
|
|
|
|
static LIST_HEAD(clocks);
|
|
static DEFINE_MUTEX(clocks_mutex);
|
|
|
|
/*-------------------------------------------------------------------------
|
|
* Standard clock functions defined in include/linux/clk.h
|
|
*-------------------------------------------------------------------------*/
|
|
|
|
static void __clk_disable(struct clk *clk)
|
|
{
|
|
if (clk == NULL || IS_ERR(clk))
|
|
return;
|
|
WARN_ON(!clk->usecount);
|
|
|
|
if (!(--clk->usecount)) {
|
|
if (clk->disable)
|
|
clk->disable(clk);
|
|
__clk_disable(clk->parent);
|
|
}
|
|
}
|
|
|
|
static int __clk_enable(struct clk *clk)
|
|
{
|
|
if (clk == NULL || IS_ERR(clk))
|
|
return -EINVAL;
|
|
|
|
if (clk->usecount++ == 0) {
|
|
__clk_enable(clk->parent);
|
|
|
|
if (clk->enable)
|
|
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 == NULL || IS_ERR(clk))
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&clocks_mutex);
|
|
ret = __clk_enable(clk);
|
|
mutex_unlock(&clocks_mutex);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(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 == NULL || IS_ERR(clk))
|
|
return;
|
|
|
|
mutex_lock(&clocks_mutex);
|
|
__clk_disable(clk);
|
|
mutex_unlock(&clocks_mutex);
|
|
}
|
|
EXPORT_SYMBOL(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 == NULL || IS_ERR(clk))
|
|
return 0UL;
|
|
|
|
if (clk->get_rate)
|
|
return clk->get_rate(clk);
|
|
|
|
return clk_get_rate(clk->parent);
|
|
}
|
|
EXPORT_SYMBOL(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 == NULL || IS_ERR(clk) || !clk->round_rate)
|
|
return 0;
|
|
|
|
return clk->round_rate(clk, rate);
|
|
}
|
|
EXPORT_SYMBOL(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 == NULL || IS_ERR(clk) || clk->set_rate == NULL || rate == 0)
|
|
return ret;
|
|
|
|
mutex_lock(&clocks_mutex);
|
|
ret = clk->set_rate(clk, rate);
|
|
mutex_unlock(&clocks_mutex);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(clk_set_rate);
|
|
|
|
/* Set the clock's parent to another clock source */
|
|
int clk_set_parent(struct clk *clk, struct clk *parent)
|
|
{
|
|
int ret = -EINVAL;
|
|
struct clk *old;
|
|
|
|
if (clk == NULL || IS_ERR(clk) || parent == NULL ||
|
|
IS_ERR(parent) || clk->set_parent == NULL)
|
|
return ret;
|
|
|
|
if (clk->usecount)
|
|
clk_enable(parent);
|
|
|
|
mutex_lock(&clocks_mutex);
|
|
ret = clk->set_parent(clk, parent);
|
|
if (ret == 0) {
|
|
old = clk->parent;
|
|
clk->parent = parent;
|
|
} else {
|
|
old = parent;
|
|
}
|
|
mutex_unlock(&clocks_mutex);
|
|
|
|
if (clk->usecount)
|
|
clk_disable(old);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(clk_set_parent);
|
|
|
|
/* Retrieve the clock's parent clock source */
|
|
struct clk *clk_get_parent(struct clk *clk)
|
|
{
|
|
struct clk *ret = NULL;
|
|
|
|
if (clk == NULL || IS_ERR(clk))
|
|
return ret;
|
|
|
|
return clk->parent;
|
|
}
|
|
EXPORT_SYMBOL(clk_get_parent);
|
|
|