linux/arch/sh/kernel/cpu/clock.c
Magnus Damm d12cfac146 sh: enable and disable clocks recursively
Recurse and make sure parent clocks get enabled/disabled.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2008-12-22 18:42:50 +09:00

365 lines
7.8 KiB
C

/*
* arch/sh/kernel/cpu/clock.c - SuperH clock framework
*
* Copyright (C) 2005, 2006, 2007 Paul Mundt
*
* This clock framework is derived from the OMAP version by:
*
* 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>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/kref.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/proc_fs.h>
#include <asm/clock.h>
#include <asm/timer.h>
static LIST_HEAD(clock_list);
static DEFINE_SPINLOCK(clock_lock);
static DEFINE_MUTEX(clock_list_sem);
/*
* Each subtype is expected to define the init routines for these clocks,
* as each subtype (or processor family) will have these clocks at the
* very least. These are all provided through the CPG, which even some of
* the more quirky parts (such as ST40, SH4-202, etc.) still have.
*
* The processor-specific code is expected to register any additional
* clock sources that are of interest.
*/
static struct clk master_clk = {
.name = "master_clk",
.flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
.rate = CONFIG_SH_PCLK_FREQ,
};
static struct clk module_clk = {
.name = "module_clk",
.parent = &master_clk,
.flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
};
static struct clk bus_clk = {
.name = "bus_clk",
.parent = &master_clk,
.flags = CLK_ALWAYS_ENABLED | CLK_RATE_PROPAGATES,
};
static struct clk cpu_clk = {
.name = "cpu_clk",
.parent = &master_clk,
.flags = CLK_ALWAYS_ENABLED,
};
/*
* The ordering of these clocks matters, do not change it.
*/
static struct clk *onchip_clocks[] = {
&master_clk,
&module_clk,
&bus_clk,
&cpu_clk,
};
static void propagate_rate(struct clk *clk)
{
struct clk *clkp;
list_for_each_entry(clkp, &clock_list, node) {
if (likely(clkp->parent != clk))
continue;
if (likely(clkp->ops && clkp->ops->recalc))
clkp->ops->recalc(clkp);
if (unlikely(clkp->flags & CLK_RATE_PROPAGATES))
propagate_rate(clkp);
}
}
static int __clk_enable(struct clk *clk)
{
/*
* See if this is the first time we're enabling the clock, some
* clocks that are always enabled still require "special"
* initialization. This is especially true if the clock mode
* changes and the clock needs to hunt for the proper set of
* divisors to use before it can effectively recalc.
*/
if (unlikely(atomic_read(&clk->kref.refcount) == 1))
if (clk->ops && clk->ops->init)
clk->ops->init(clk);
kref_get(&clk->kref);
if (clk->flags & CLK_ALWAYS_ENABLED)
return 0;
if (likely(clk->ops && clk->ops->enable))
clk->ops->enable(clk);
return 0;
}
int clk_enable(struct clk *clk)
{
unsigned long flags;
int ret;
if (!clk)
return -EINVAL;
clk_enable(clk->parent);
spin_lock_irqsave(&clock_lock, flags);
ret = __clk_enable(clk);
spin_unlock_irqrestore(&clock_lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(clk_enable);
static void clk_kref_release(struct kref *kref)
{
/* Nothing to do */
}
static void __clk_disable(struct clk *clk)
{
int count = kref_put(&clk->kref, clk_kref_release);
if (clk->flags & CLK_ALWAYS_ENABLED)
return;
if (!count) { /* count reaches zero, disable the clock */
if (likely(clk->ops && clk->ops->disable))
clk->ops->disable(clk);
}
}
void clk_disable(struct clk *clk)
{
unsigned long flags;
if (!clk)
return -EINVAL;
spin_lock_irqsave(&clock_lock, flags);
__clk_disable(clk);
spin_unlock_irqrestore(&clock_lock, flags);
clk_disable(clk->parent);
}
EXPORT_SYMBOL_GPL(clk_disable);
int clk_register(struct clk *clk)
{
mutex_lock(&clock_list_sem);
list_add(&clk->node, &clock_list);
kref_init(&clk->kref);
mutex_unlock(&clock_list_sem);
if (clk->flags & CLK_ALWAYS_ENABLED) {
pr_debug( "Clock '%s' is ALWAYS_ENABLED\n", clk->name);
if (clk->ops && clk->ops->init)
clk->ops->init(clk);
if (clk->ops && clk->ops->enable)
clk->ops->enable(clk);
pr_debug( "Enabled.");
}
return 0;
}
EXPORT_SYMBOL_GPL(clk_register);
void clk_unregister(struct clk *clk)
{
mutex_lock(&clock_list_sem);
list_del(&clk->node);
mutex_unlock(&clock_list_sem);
}
EXPORT_SYMBOL_GPL(clk_unregister);
unsigned long clk_get_rate(struct clk *clk)
{
return clk->rate;
}
EXPORT_SYMBOL_GPL(clk_get_rate);
int clk_set_rate(struct clk *clk, unsigned long rate)
{
return clk_set_rate_ex(clk, rate, 0);
}
EXPORT_SYMBOL_GPL(clk_set_rate);
int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
{
int ret = -EOPNOTSUPP;
if (likely(clk->ops && clk->ops->set_rate)) {
unsigned long flags;
spin_lock_irqsave(&clock_lock, flags);
ret = clk->ops->set_rate(clk, rate, algo_id);
spin_unlock_irqrestore(&clock_lock, flags);
}
if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
propagate_rate(clk);
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate_ex);
void clk_recalc_rate(struct clk *clk)
{
if (likely(clk->ops && clk->ops->recalc)) {
unsigned long flags;
spin_lock_irqsave(&clock_lock, flags);
clk->ops->recalc(clk);
spin_unlock_irqrestore(&clock_lock, flags);
}
if (unlikely(clk->flags & CLK_RATE_PROPAGATES))
propagate_rate(clk);
}
EXPORT_SYMBOL_GPL(clk_recalc_rate);
long clk_round_rate(struct clk *clk, unsigned long rate)
{
if (likely(clk->ops && clk->ops->round_rate)) {
unsigned long flags, rounded;
spin_lock_irqsave(&clock_lock, flags);
rounded = clk->ops->round_rate(clk, rate);
spin_unlock_irqrestore(&clock_lock, flags);
return rounded;
}
return clk_get_rate(clk);
}
EXPORT_SYMBOL_GPL(clk_round_rate);
/*
* Returns a clock. Note that we first try to use device id on the bus
* and clock name. If this fails, we try to use clock name only.
*/
struct clk *clk_get(struct device *dev, const char *id)
{
struct clk *p, *clk = ERR_PTR(-ENOENT);
int idno;
if (dev == NULL || dev->bus != &platform_bus_type)
idno = -1;
else
idno = to_platform_device(dev)->id;
mutex_lock(&clock_list_sem);
list_for_each_entry(p, &clock_list, node) {
if (p->id == idno &&
strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
clk = p;
goto found;
}
}
list_for_each_entry(p, &clock_list, node) {
if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
clk = p;
break;
}
}
found:
mutex_unlock(&clock_list_sem);
return clk;
}
EXPORT_SYMBOL_GPL(clk_get);
void clk_put(struct clk *clk)
{
if (clk && !IS_ERR(clk))
module_put(clk->owner);
}
EXPORT_SYMBOL_GPL(clk_put);
void __init __attribute__ ((weak))
arch_init_clk_ops(struct clk_ops **ops, int type)
{
}
int __init __attribute__ ((weak))
arch_clk_init(void)
{
return 0;
}
static int show_clocks(char *buf, char **start, off_t off,
int len, int *eof, void *data)
{
struct clk *clk;
char *p = buf;
list_for_each_entry_reverse(clk, &clock_list, node) {
unsigned long rate = clk_get_rate(clk);
p += sprintf(p, "%-12s\t: %ld.%02ldMHz\t%s\n", clk->name,
rate / 1000000, (rate % 1000000) / 10000,
((clk->flags & CLK_ALWAYS_ENABLED) ||
(atomic_read(&clk->kref.refcount) != 1)) ?
"enabled" : "disabled");
}
return p - buf;
}
int __init clk_init(void)
{
int i, ret = 0;
BUG_ON(!master_clk.rate);
for (i = 0; i < ARRAY_SIZE(onchip_clocks); i++) {
struct clk *clk = onchip_clocks[i];
arch_init_clk_ops(&clk->ops, i);
ret |= clk_register(clk);
}
ret |= arch_clk_init();
/* Kick the child clocks.. */
propagate_rate(&master_clk);
propagate_rate(&bus_clk);
return ret;
}
static int __init clk_proc_init(void)
{
struct proc_dir_entry *p;
p = create_proc_read_entry("clocks", S_IRUSR, NULL,
show_clocks, NULL);
if (unlikely(!p))
return -EINVAL;
return 0;
}
subsys_initcall(clk_proc_init);