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r: 100870
b: refs/heads/master
c: c0db2ea
h: refs/heads/master
v: v3
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Juergen Beisert authored and Robert Schwebel committed Jul 5, 2008
1 parent 4b0e2e0 commit 8dfc8ba
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: 38a41fdf94c449c165213e4665c3f8a0d30f8aba
refs/heads/master: c0db2ea4e366c94dd3f880928c02534156e3d1b9
2 changes: 1 addition & 1 deletion trunk/arch/arm/plat-mxc/Makefile
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#

# Common support
obj-y := irq.o
obj-y := irq.o clock.o
331 changes: 331 additions & 0 deletions trunk/arch/arm/plat-mxc/clock.c
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/*
* 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 <linux/version.h>

#include <asm/arch/clock.h>

static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);

/*-------------------------------------------------------------------------
* Standard clock functions defined in include/linux/clk.h
*-------------------------------------------------------------------------*/

/*
* Retrieve a clock by name.
*
* Note that we first try to use device id on the bus
* and clock name. If this fails, we try to use "<name>.<id>". If this fails,
* we try to use clock name only.
* The reference count to the clock's module owner ref count is incremented.
*/
struct clk *clk_get(struct device *dev, const char *id)
{
struct clk *p, *clk = ERR_PTR(-ENOENT);
int idno;
const char *str;

if (id == NULL)
return clk;

if (dev == NULL || dev->bus != &platform_bus_type)
idno = -1;
else
idno = to_platform_device(dev)->id;

mutex_lock(&clocks_mutex);

list_for_each_entry(p, &clocks, node) {
if (p->id == idno &&
strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
clk = p;
goto found;
}
}

str = strrchr(id, '.');
if (str) {
int cnt = str - id;
str++;
idno = simple_strtol(str, NULL, 10);
list_for_each_entry(p, &clocks, node) {
if (p->id == idno &&
strlen(p->name) == cnt &&
strncmp(id, p->name, cnt) == 0 &&
try_module_get(p->owner)) {
clk = p;
goto found;
}
}
}

list_for_each_entry(p, &clocks, node) {
if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
clk = p;
goto found;
}
}

printk(KERN_WARNING "clk: Unable to get requested clock: %s\n", id);

found:
mutex_unlock(&clocks_mutex);

return clk;
}
EXPORT_SYMBOL(clk_get);

static void __clk_disable(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return;

__clk_disable(clk->parent);
__clk_disable(clk->secondary);

if (!(--clk->usecount) && clk->disable)
clk->disable(clk);
}

static int __clk_enable(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return -EINVAL;

__clk_enable(clk->parent);
__clk_enable(clk->secondary);

if (clk->usecount++ == 0 && 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);

/* Decrement the clock's module reference count */
void clk_put(struct clk *clk)
{
if (clk && !IS_ERR(clk))
module_put(clk->owner);
}
EXPORT_SYMBOL(clk_put);

/* 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;

if (clk == NULL || IS_ERR(clk) || parent == NULL ||
IS_ERR(parent) || clk->set_parent == NULL)
return ret;

mutex_lock(&clocks_mutex);
ret = clk->set_parent(clk, parent);
if (ret == 0)
clk->parent = parent;
mutex_unlock(&clocks_mutex);

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);

/*
* Add a new clock to the clock tree.
*/
int clk_register(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return -EINVAL;

mutex_lock(&clocks_mutex);
list_add(&clk->node, &clocks);
mutex_unlock(&clocks_mutex);

return 0;
}
EXPORT_SYMBOL(clk_register);

/* Remove a clock from the clock tree */
void clk_unregister(struct clk *clk)
{
if (clk == NULL || IS_ERR(clk))
return;

mutex_lock(&clocks_mutex);
list_del(&clk->node);
mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clk_unregister);

#ifdef CONFIG_PROC_FS
static int mxc_clock_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
struct clk *clkp;
char *p = page;
int len;

list_for_each_entry(clkp, &clocks, node) {
p += sprintf(p, "%s-%d:\t\t%lu, %d", clkp->name, clkp->id,
clk_get_rate(clkp), clkp->usecount);
if (clkp->parent)
p += sprintf(p, ", %s-%d\n", clkp->parent->name,
clkp->parent->id);
else
p += sprintf(p, "\n");
}

len = (p - page) - off;
if (len < 0)
len = 0;

*eof = (len <= count) ? 1 : 0;
*start = page + off;

return len;
}

static int __init mxc_setup_proc_entry(void)
{
struct proc_dir_entry *res;

res = create_proc_read_entry("cpu/clocks", 0, NULL,
mxc_clock_read_proc, NULL);
if (!res) {
printk(KERN_ERR "Failed to create proc/cpu/clocks\n");
return -ENOMEM;
}
return 0;
}

late_initcall(mxc_setup_proc_entry);
#endif
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