/*
* 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
