linux/arch/arm/plat-s3c/clock.c
Ben Dooks 3ac19bb443 [ARM] S3C: Do not set clk->owner field if unset
The s3c24xx_register_clock() function has been doing a test
on clk->owner to see if it is NULL, and then setting itself
as the owner if clk->owner == NULL.

This is not needed, arch/arm/plat-s3c/clock.c cannot be
compiled as a module, and even if it was, it should not be
playing with this field if it being registered from somewhere
else.

The best course of action is to remove this bit of
code completely.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 15:21:57 +01:00

367 lines
6.9 KiB
C

/* linux/arch/arm/plat-s3c24xx/clock.c
*
* Copyright (c) 2004-2005 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* S3C24XX Core clock control support
*
* Based on, and code from linux/arch/arm/mach-versatile/clock.c
**
** Copyright (C) 2004 ARM Limited.
** Written by Deep Blue Solutions Limited.
*
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/sysdev.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/clk.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <plat/cpu-freq.h>
#include <plat/clock.h>
#include <plat/cpu.h>
/* clock information */
static LIST_HEAD(clocks);
/* We originally used an mutex here, but some contexts (see resume)
* are calling functions such as clk_set_parent() with IRQs disabled
* causing an BUG to be triggered.
*/
DEFINE_SPINLOCK(clocks_lock);
/* enable and disable calls for use with the clk struct */
static int clk_null_enable(struct clk *clk, int enable)
{
return 0;
}
/* Clock API calls */
struct clk *clk_get(struct device *dev, const char *id)
{
struct clk *p;
struct clk *clk = ERR_PTR(-ENOENT);
int idno;
if (dev == NULL || dev->bus != &platform_bus_type)
idno = -1;
else
idno = to_platform_device(dev)->id;
spin_lock(&clocks_lock);
list_for_each_entry(p, &clocks, list) {
if (p->id == idno &&
strcmp(id, p->name) == 0 &&
try_module_get(p->owner)) {
clk = p;
break;
}
}
/* check for the case where a device was supplied, but the
* clock that was being searched for is not device specific */
if (IS_ERR(clk)) {
list_for_each_entry(p, &clocks, list) {
if (p->id == -1 && strcmp(id, p->name) == 0 &&
try_module_get(p->owner)) {
clk = p;
break;
}
}
}
spin_unlock(&clocks_lock);
return clk;
}
void clk_put(struct clk *clk)
{
module_put(clk->owner);
}
int clk_enable(struct clk *clk)
{
if (IS_ERR(clk) || clk == NULL)
return -EINVAL;
clk_enable(clk->parent);
spin_lock(&clocks_lock);
if ((clk->usage++) == 0)
(clk->enable)(clk, 1);
spin_unlock(&clocks_lock);
return 0;
}
void clk_disable(struct clk *clk)
{
if (IS_ERR(clk) || clk == NULL)
return;
spin_lock(&clocks_lock);
if ((--clk->usage) == 0)
(clk->enable)(clk, 0);
spin_unlock(&clocks_lock);
clk_disable(clk->parent);
}
unsigned long clk_get_rate(struct clk *clk)
{
if (IS_ERR(clk))
return 0;
if (clk->rate != 0)
return clk->rate;
if (clk->get_rate != NULL)
return (clk->get_rate)(clk);
if (clk->parent != NULL)
return clk_get_rate(clk->parent);
return clk->rate;
}
long clk_round_rate(struct clk *clk, unsigned long rate)
{
if (!IS_ERR(clk) && clk->round_rate)
return (clk->round_rate)(clk, rate);
return rate;
}
int clk_set_rate(struct clk *clk, unsigned long rate)
{
int ret;
if (IS_ERR(clk))
return -EINVAL;
/* We do not default just do a clk->rate = rate as
* the clock may have been made this way by choice.
*/
WARN_ON(clk->set_rate == NULL);
if (clk->set_rate == NULL)
return -EINVAL;
spin_lock(&clocks_lock);
ret = (clk->set_rate)(clk, rate);
spin_unlock(&clocks_lock);
return ret;
}
struct clk *clk_get_parent(struct clk *clk)
{
return clk->parent;
}
int clk_set_parent(struct clk *clk, struct clk *parent)
{
int ret = 0;
if (IS_ERR(clk))
return -EINVAL;
spin_lock(&clocks_lock);
if (clk->set_parent)
ret = (clk->set_parent)(clk, parent);
spin_unlock(&clocks_lock);
return ret;
}
EXPORT_SYMBOL(clk_get);
EXPORT_SYMBOL(clk_put);
EXPORT_SYMBOL(clk_enable);
EXPORT_SYMBOL(clk_disable);
EXPORT_SYMBOL(clk_get_rate);
EXPORT_SYMBOL(clk_round_rate);
EXPORT_SYMBOL(clk_set_rate);
EXPORT_SYMBOL(clk_get_parent);
EXPORT_SYMBOL(clk_set_parent);
/* base clocks */
static int clk_default_setrate(struct clk *clk, unsigned long rate)
{
clk->rate = rate;
return 0;
}
struct clk clk_xtal = {
.name = "xtal",
.id = -1,
.rate = 0,
.parent = NULL,
.ctrlbit = 0,
};
struct clk clk_ext = {
.name = "ext",
.id = -1,
};
struct clk clk_epll = {
.name = "epll",
.id = -1,
};
struct clk clk_mpll = {
.name = "mpll",
.id = -1,
.set_rate = clk_default_setrate,
};
struct clk clk_upll = {
.name = "upll",
.id = -1,
.parent = NULL,
.ctrlbit = 0,
};
struct clk clk_f = {
.name = "fclk",
.id = -1,
.rate = 0,
.parent = &clk_mpll,
.ctrlbit = 0,
.set_rate = clk_default_setrate,
};
struct clk clk_h = {
.name = "hclk",
.id = -1,
.rate = 0,
.parent = NULL,
.ctrlbit = 0,
.set_rate = clk_default_setrate,
};
struct clk clk_p = {
.name = "pclk",
.id = -1,
.rate = 0,
.parent = NULL,
.ctrlbit = 0,
.set_rate = clk_default_setrate,
};
struct clk clk_usb_bus = {
.name = "usb-bus",
.id = -1,
.rate = 0,
.parent = &clk_upll,
};
struct clk s3c24xx_uclk = {
.name = "uclk",
.id = -1,
};
/* initialise the clock system */
int s3c24xx_register_clock(struct clk *clk)
{
if (clk->enable == NULL)
clk->enable = clk_null_enable;
/* add to the list of available clocks */
/* Quick check to see if this clock has already been registered. */
BUG_ON(clk->list.prev != clk->list.next);
spin_lock(&clocks_lock);
list_add(&clk->list, &clocks);
spin_unlock(&clocks_lock);
return 0;
}
int s3c24xx_register_clocks(struct clk **clks, int nr_clks)
{
int fails = 0;
for (; nr_clks > 0; nr_clks--, clks++) {
if (s3c24xx_register_clock(*clks) < 0)
fails++;
}
return fails;
}
/* initalise all the clocks */
int __init s3c24xx_register_baseclocks(unsigned long xtal)
{
printk(KERN_INFO "S3C24XX Clocks, (c) 2004 Simtec Electronics\n");
clk_xtal.rate = xtal;
/* register our clocks */
if (s3c24xx_register_clock(&clk_xtal) < 0)
printk(KERN_ERR "failed to register master xtal\n");
if (s3c24xx_register_clock(&clk_mpll) < 0)
printk(KERN_ERR "failed to register mpll clock\n");
if (s3c24xx_register_clock(&clk_upll) < 0)
printk(KERN_ERR "failed to register upll clock\n");
if (s3c24xx_register_clock(&clk_f) < 0)
printk(KERN_ERR "failed to register cpu fclk\n");
if (s3c24xx_register_clock(&clk_h) < 0)
printk(KERN_ERR "failed to register cpu hclk\n");
if (s3c24xx_register_clock(&clk_p) < 0)
printk(KERN_ERR "failed to register cpu pclk\n");
return 0;
}