linux/drivers/sh/clk.c

546 lines
11 KiB
C

/*
* drivers/sh/clk.c - SuperH clock framework
*
* Copyright (C) 2005 - 2009 Paul Mundt
*
* This clock framework is derived from the OMAP version by:
*
* Copyright (C) 2004 - 2008 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/kobject.h>
#include <linux/sysdev.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/debugfs.h>
#include <linux/cpufreq.h>
#include <linux/clk.h>
#include <linux/sh_clk.h>
static LIST_HEAD(clock_list);
static DEFINE_SPINLOCK(clock_lock);
static DEFINE_MUTEX(clock_list_sem);
void clk_rate_table_build(struct clk *clk,
struct cpufreq_frequency_table *freq_table,
int nr_freqs,
struct clk_div_mult_table *src_table,
unsigned long *bitmap)
{
unsigned long mult, div;
unsigned long freq;
int i;
for (i = 0; i < nr_freqs; i++) {
div = 1;
mult = 1;
if (src_table->divisors && i < src_table->nr_divisors)
div = src_table->divisors[i];
if (src_table->multipliers && i < src_table->nr_multipliers)
mult = src_table->multipliers[i];
if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
freq = CPUFREQ_ENTRY_INVALID;
else
freq = clk->parent->rate * mult / div;
freq_table[i].index = i;
freq_table[i].frequency = freq;
}
/* Termination entry */
freq_table[i].index = i;
freq_table[i].frequency = CPUFREQ_TABLE_END;
}
long clk_rate_table_round(struct clk *clk,
struct cpufreq_frequency_table *freq_table,
unsigned long rate)
{
unsigned long rate_error, rate_error_prev = ~0UL;
unsigned long rate_best_fit = rate;
unsigned long highest, lowest;
int i;
highest = lowest = 0;
for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
unsigned long freq = freq_table[i].frequency;
if (freq == CPUFREQ_ENTRY_INVALID)
continue;
if (freq > highest)
highest = freq;
if (freq < lowest)
lowest = freq;
rate_error = abs(freq - rate);
if (rate_error < rate_error_prev) {
rate_best_fit = freq;
rate_error_prev = rate_error;
}
if (rate_error == 0)
break;
}
if (rate >= highest)
rate_best_fit = highest;
if (rate <= lowest)
rate_best_fit = lowest;
return rate_best_fit;
}
int clk_rate_table_find(struct clk *clk,
struct cpufreq_frequency_table *freq_table,
unsigned long rate)
{
int i;
for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
unsigned long freq = freq_table[i].frequency;
if (freq == CPUFREQ_ENTRY_INVALID)
continue;
if (freq == rate)
return i;
}
return -ENOENT;
}
/* Used for clocks that always have same value as the parent clock */
unsigned long followparent_recalc(struct clk *clk)
{
return clk->parent ? clk->parent->rate : 0;
}
int clk_reparent(struct clk *child, struct clk *parent)
{
list_del_init(&child->sibling);
if (parent)
list_add(&child->sibling, &parent->children);
child->parent = parent;
/* now do the debugfs renaming to reattach the child
to the proper parent */
return 0;
}
/* Propagate rate to children */
void propagate_rate(struct clk *tclk)
{
struct clk *clkp;
list_for_each_entry(clkp, &tclk->children, sibling) {
if (clkp->ops && clkp->ops->recalc)
clkp->rate = clkp->ops->recalc(clkp);
propagate_rate(clkp);
}
}
static void __clk_disable(struct clk *clk)
{
if (WARN(!clk->usecount, "Trying to disable clock %s with 0 usecount\n",
clk->name))
return;
if (!(--clk->usecount)) {
if (likely(clk->ops && clk->ops->disable))
clk->ops->disable(clk);
if (likely(clk->parent))
__clk_disable(clk->parent);
}
}
void clk_disable(struct clk *clk)
{
unsigned long flags;
if (!clk)
return;
spin_lock_irqsave(&clock_lock, flags);
__clk_disable(clk);
spin_unlock_irqrestore(&clock_lock, flags);
}
EXPORT_SYMBOL_GPL(clk_disable);
static int __clk_enable(struct clk *clk)
{
int ret = 0;
if (clk->usecount++ == 0) {
if (clk->parent) {
ret = __clk_enable(clk->parent);
if (unlikely(ret))
goto err;
}
if (clk->ops && clk->ops->enable) {
ret = clk->ops->enable(clk);
if (ret) {
if (clk->parent)
__clk_disable(clk->parent);
goto err;
}
}
}
return ret;
err:
clk->usecount--;
return ret;
}
int clk_enable(struct clk *clk)
{
unsigned long flags;
int ret;
if (!clk)
return -EINVAL;
spin_lock_irqsave(&clock_lock, flags);
ret = __clk_enable(clk);
spin_unlock_irqrestore(&clock_lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(clk_enable);
static LIST_HEAD(root_clks);
/**
* recalculate_root_clocks - recalculate and propagate all root clocks
*
* Recalculates all root clocks (clocks with no parent), which if the
* clock's .recalc is set correctly, should also propagate their rates.
* Called at init.
*/
void recalculate_root_clocks(void)
{
struct clk *clkp;
list_for_each_entry(clkp, &root_clks, sibling) {
if (clkp->ops && clkp->ops->recalc)
clkp->rate = clkp->ops->recalc(clkp);
propagate_rate(clkp);
}
}
int clk_register(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return -EINVAL;
/*
* trap out already registered clocks
*/
if (clk->node.next || clk->node.prev)
return 0;
mutex_lock(&clock_list_sem);
INIT_LIST_HEAD(&clk->children);
clk->usecount = 0;
if (clk->parent)
list_add(&clk->sibling, &clk->parent->children);
else
list_add(&clk->sibling, &root_clks);
list_add(&clk->node, &clock_list);
if (clk->ops && clk->ops->init)
clk->ops->init(clk);
mutex_unlock(&clock_list_sem);
return 0;
}
EXPORT_SYMBOL_GPL(clk_register);
void clk_unregister(struct clk *clk)
{
mutex_lock(&clock_list_sem);
list_del(&clk->sibling);
list_del(&clk->node);
mutex_unlock(&clock_list_sem);
}
EXPORT_SYMBOL_GPL(clk_unregister);
void clk_enable_init_clocks(void)
{
struct clk *clkp;
list_for_each_entry(clkp, &clock_list, node)
if (clkp->flags & CLK_ENABLE_ON_INIT)
clk_enable(clkp);
}
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;
unsigned long flags;
spin_lock_irqsave(&clock_lock, flags);
if (likely(clk->ops && clk->ops->set_rate)) {
ret = clk->ops->set_rate(clk, rate, algo_id);
if (ret != 0)
goto out_unlock;
} else {
clk->rate = rate;
ret = 0;
}
if (clk->ops && clk->ops->recalc)
clk->rate = clk->ops->recalc(clk);
propagate_rate(clk);
out_unlock:
spin_unlock_irqrestore(&clock_lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate_ex);
int clk_set_parent(struct clk *clk, struct clk *parent)
{
unsigned long flags;
int ret = -EINVAL;
if (!parent || !clk)
return ret;
if (clk->parent == parent)
return 0;
spin_lock_irqsave(&clock_lock, flags);
if (clk->usecount == 0) {
if (clk->ops->set_parent)
ret = clk->ops->set_parent(clk, parent);
else
ret = clk_reparent(clk, parent);
if (ret == 0) {
pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
clk->name, clk->parent->name, clk->rate);
if (clk->ops->recalc)
clk->rate = clk->ops->recalc(clk);
propagate_rate(clk);
}
} else
ret = -EBUSY;
spin_unlock_irqrestore(&clock_lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(clk_set_parent);
struct clk *clk_get_parent(struct clk *clk)
{
return clk->parent;
}
EXPORT_SYMBOL_GPL(clk_get_parent);
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);
#ifdef CONFIG_PM
static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
{
static pm_message_t prev_state;
struct clk *clkp;
switch (state.event) {
case PM_EVENT_ON:
/* Resumeing from hibernation */
if (prev_state.event != PM_EVENT_FREEZE)
break;
list_for_each_entry(clkp, &clock_list, node) {
if (likely(clkp->ops)) {
unsigned long rate = clkp->rate;
if (likely(clkp->ops->set_parent))
clkp->ops->set_parent(clkp,
clkp->parent);
if (likely(clkp->ops->set_rate))
clkp->ops->set_rate(clkp,
rate, NO_CHANGE);
else if (likely(clkp->ops->recalc))
clkp->rate = clkp->ops->recalc(clkp);
}
}
break;
case PM_EVENT_FREEZE:
break;
case PM_EVENT_SUSPEND:
break;
}
prev_state = state;
return 0;
}
static int clks_sysdev_resume(struct sys_device *dev)
{
return clks_sysdev_suspend(dev, PMSG_ON);
}
static struct sysdev_class clks_sysdev_class = {
.name = "clks",
};
static struct sysdev_driver clks_sysdev_driver = {
.suspend = clks_sysdev_suspend,
.resume = clks_sysdev_resume,
};
static struct sys_device clks_sysdev_dev = {
.cls = &clks_sysdev_class,
};
static int __init clk_sysdev_init(void)
{
sysdev_class_register(&clks_sysdev_class);
sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
sysdev_register(&clks_sysdev_dev);
return 0;
}
subsys_initcall(clk_sysdev_init);
#endif
/*
* debugfs support to trace clock tree hierarchy and attributes
*/
static struct dentry *clk_debugfs_root;
static int clk_debugfs_register_one(struct clk *c)
{
int err;
struct dentry *d, *child, *child_tmp;
struct clk *pa = c->parent;
char s[255];
char *p = s;
p += sprintf(p, "%s", c->name);
if (c->id >= 0)
sprintf(p, ":%d", c->id);
d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
if (!d)
return -ENOMEM;
c->dentry = d;
d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
if (!d) {
err = -ENOMEM;
goto err_out;
}
d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
if (!d) {
err = -ENOMEM;
goto err_out;
}
d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
if (!d) {
err = -ENOMEM;
goto err_out;
}
return 0;
err_out:
d = c->dentry;
list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
debugfs_remove(child);
debugfs_remove(c->dentry);
return err;
}
static int clk_debugfs_register(struct clk *c)
{
int err;
struct clk *pa = c->parent;
if (pa && !pa->dentry) {
err = clk_debugfs_register(pa);
if (err)
return err;
}
if (!c->dentry && c->name) {
err = clk_debugfs_register_one(c);
if (err)
return err;
}
return 0;
}
static int __init clk_debugfs_init(void)
{
struct clk *c;
struct dentry *d;
int err;
d = debugfs_create_dir("clock", NULL);
if (!d)
return -ENOMEM;
clk_debugfs_root = d;
list_for_each_entry(c, &clock_list, node) {
err = clk_debugfs_register(c);
if (err)
goto err_out;
}
return 0;
err_out:
debugfs_remove_recursive(clk_debugfs_root);
return err;
}
late_initcall(clk_debugfs_init);