mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 13:55:32 +00:00
![Hans J. Koch](/assets/img/avatar_default.png)
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>
179 lines
3.9 KiB
C
179 lines
3.9 KiB
C
/*
|
|
* 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);
|