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![Sascha Hauer](/assets/img/avatar_default.png)
This patch only adds general clkdev support without actually switching any MXC architecture to clkdev. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
384 lines
8.6 KiB
C
384 lines
8.6 KiB
C
/*
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* Based on arch/arm/plat-omap/clock.c
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*
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* Copyright (C) 2004 - 2005 Nokia corporation
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* Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
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* Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
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* Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
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* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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/* #define DEBUG */
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/platform_device.h>
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#include <linux/proc_fs.h>
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#include <linux/semaphore.h>
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#include <linux/string.h>
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#include <mach/clock.h>
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static LIST_HEAD(clocks);
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static DEFINE_MUTEX(clocks_mutex);
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/*-------------------------------------------------------------------------
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* Standard clock functions defined in include/linux/clk.h
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*-------------------------------------------------------------------------*/
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/*
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* All the code inside #ifndef CONFIG_COMMON_CLKDEV can be removed once all
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* MXC architectures have switched to using clkdev.
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*/
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#ifndef CONFIG_COMMON_CLKDEV
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/*
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* Retrieve a clock by name.
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*
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* Note that we first try to use device id on the bus
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* and clock name. If this fails, we try to use "<name>.<id>". If this fails,
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* we try to use clock name only.
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* The reference count to the clock's module owner ref count is incremented.
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*/
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struct clk *clk_get(struct device *dev, const char *id)
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{
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struct clk *p, *clk = ERR_PTR(-ENOENT);
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int idno;
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const char *str;
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if (id == NULL)
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return clk;
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if (dev == NULL || dev->bus != &platform_bus_type)
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idno = -1;
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else
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idno = to_platform_device(dev)->id;
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mutex_lock(&clocks_mutex);
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list_for_each_entry(p, &clocks, node) {
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if (p->id == idno &&
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strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
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clk = p;
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goto found;
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}
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}
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str = strrchr(id, '.');
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if (str) {
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int cnt = str - id;
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str++;
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idno = simple_strtol(str, NULL, 10);
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list_for_each_entry(p, &clocks, node) {
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if (p->id == idno &&
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strlen(p->name) == cnt &&
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strncmp(id, p->name, cnt) == 0 &&
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try_module_get(p->owner)) {
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clk = p;
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goto found;
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}
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}
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}
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list_for_each_entry(p, &clocks, node) {
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if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
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clk = p;
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goto found;
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}
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}
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printk(KERN_WARNING "clk: Unable to get requested clock: %s\n", id);
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found:
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mutex_unlock(&clocks_mutex);
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return clk;
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}
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EXPORT_SYMBOL(clk_get);
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#endif
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static void __clk_disable(struct clk *clk)
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{
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if (clk == NULL || IS_ERR(clk))
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return;
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__clk_disable(clk->parent);
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__clk_disable(clk->secondary);
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if (!(--clk->usecount) && clk->disable)
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clk->disable(clk);
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}
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static int __clk_enable(struct clk *clk)
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{
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if (clk == NULL || IS_ERR(clk))
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return -EINVAL;
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__clk_enable(clk->parent);
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__clk_enable(clk->secondary);
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if (clk->usecount++ == 0 && clk->enable)
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clk->enable(clk);
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return 0;
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}
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/* This function increments the reference count on the clock and enables the
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* clock if not already enabled. The parent clock tree is recursively enabled
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*/
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int clk_enable(struct clk *clk)
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{
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int ret = 0;
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if (clk == NULL || IS_ERR(clk))
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return -EINVAL;
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mutex_lock(&clocks_mutex);
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ret = __clk_enable(clk);
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mutex_unlock(&clocks_mutex);
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return ret;
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}
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EXPORT_SYMBOL(clk_enable);
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/* This function decrements the reference count on the clock and disables
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* the clock when reference count is 0. The parent clock tree is
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* recursively disabled
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*/
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void clk_disable(struct clk *clk)
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{
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if (clk == NULL || IS_ERR(clk))
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return;
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mutex_lock(&clocks_mutex);
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__clk_disable(clk);
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mutex_unlock(&clocks_mutex);
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}
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EXPORT_SYMBOL(clk_disable);
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/* Retrieve the *current* clock rate. If the clock itself
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* does not provide a special calculation routine, ask
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* its parent and so on, until one is able to return
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* a valid clock rate
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*/
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unsigned long clk_get_rate(struct clk *clk)
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{
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if (clk == NULL || IS_ERR(clk))
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return 0UL;
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if (clk->get_rate)
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return clk->get_rate(clk);
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return clk_get_rate(clk->parent);
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}
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EXPORT_SYMBOL(clk_get_rate);
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#ifndef CONFIG_COMMON_CLKDEV
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/* Decrement the clock's module reference count */
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void clk_put(struct clk *clk)
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{
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if (clk && !IS_ERR(clk))
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module_put(clk->owner);
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}
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EXPORT_SYMBOL(clk_put);
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#endif
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/* Round the requested clock rate to the nearest supported
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* rate that is less than or equal to the requested rate.
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* This is dependent on the clock's current parent.
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*/
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long clk_round_rate(struct clk *clk, unsigned long rate)
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{
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if (clk == NULL || IS_ERR(clk) || !clk->round_rate)
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return 0;
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return clk->round_rate(clk, rate);
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}
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EXPORT_SYMBOL(clk_round_rate);
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/* Set the clock to the requested clock rate. The rate must
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* match a supported rate exactly based on what clk_round_rate returns
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*/
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int clk_set_rate(struct clk *clk, unsigned long rate)
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{
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int ret = -EINVAL;
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if (clk == NULL || IS_ERR(clk) || clk->set_rate == NULL || rate == 0)
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return ret;
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mutex_lock(&clocks_mutex);
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ret = clk->set_rate(clk, rate);
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mutex_unlock(&clocks_mutex);
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return ret;
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}
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EXPORT_SYMBOL(clk_set_rate);
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/* Set the clock's parent to another clock source */
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int clk_set_parent(struct clk *clk, struct clk *parent)
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{
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int ret = -EINVAL;
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if (clk == NULL || IS_ERR(clk) || parent == NULL ||
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IS_ERR(parent) || clk->set_parent == NULL)
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return ret;
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mutex_lock(&clocks_mutex);
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ret = clk->set_parent(clk, parent);
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if (ret == 0)
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clk->parent = parent;
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mutex_unlock(&clocks_mutex);
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return ret;
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}
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EXPORT_SYMBOL(clk_set_parent);
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/* Retrieve the clock's parent clock source */
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struct clk *clk_get_parent(struct clk *clk)
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{
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struct clk *ret = NULL;
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if (clk == NULL || IS_ERR(clk))
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return ret;
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return clk->parent;
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}
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EXPORT_SYMBOL(clk_get_parent);
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#ifndef CONFIG_COMMON_CLKDEV
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/*
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* Add a new clock to the clock tree.
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*/
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int clk_register(struct clk *clk)
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{
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if (clk == NULL || IS_ERR(clk))
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return -EINVAL;
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mutex_lock(&clocks_mutex);
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list_add(&clk->node, &clocks);
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mutex_unlock(&clocks_mutex);
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return 0;
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}
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EXPORT_SYMBOL(clk_register);
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/* Remove a clock from the clock tree */
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void clk_unregister(struct clk *clk)
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{
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if (clk == NULL || IS_ERR(clk))
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return;
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mutex_lock(&clocks_mutex);
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list_del(&clk->node);
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mutex_unlock(&clocks_mutex);
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}
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EXPORT_SYMBOL(clk_unregister);
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#ifdef CONFIG_PROC_FS
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static int mxc_clock_read_proc(char *page, char **start, off_t off,
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int count, int *eof, void *data)
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{
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struct clk *clkp;
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char *p = page;
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int len;
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list_for_each_entry(clkp, &clocks, node) {
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p += sprintf(p, "%s-%d:\t\t%lu, %d", clkp->name, clkp->id,
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clk_get_rate(clkp), clkp->usecount);
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if (clkp->parent)
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p += sprintf(p, ", %s-%d\n", clkp->parent->name,
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clkp->parent->id);
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else
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p += sprintf(p, "\n");
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}
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len = (p - page) - off;
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if (len < 0)
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len = 0;
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*eof = (len <= count) ? 1 : 0;
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*start = page + off;
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return len;
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}
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static int __init mxc_setup_proc_entry(void)
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{
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struct proc_dir_entry *res;
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res = create_proc_read_entry("cpu/clocks", 0, NULL,
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mxc_clock_read_proc, NULL);
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if (!res) {
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printk(KERN_ERR "Failed to create proc/cpu/clocks\n");
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return -ENOMEM;
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}
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return 0;
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}
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late_initcall(mxc_setup_proc_entry);
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#endif /* CONFIG_PROC_FS */
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#endif
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/*
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* Get the resulting clock rate from a PLL register value and the input
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* frequency. PLLs with this register layout can at least be found on
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* MX1, MX21, MX27 and MX31
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*
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* mfi + mfn / (mfd + 1)
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* f = 2 * f_ref * --------------------
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* pd + 1
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*/
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unsigned long mxc_decode_pll(unsigned int reg_val, u32 freq)
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{
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long long ll;
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int mfn_abs;
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unsigned int mfi, mfn, mfd, pd;
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mfi = (reg_val >> 10) & 0xf;
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mfn = reg_val & 0x3ff;
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mfd = (reg_val >> 16) & 0x3ff;
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pd = (reg_val >> 26) & 0xf;
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mfi = mfi <= 5 ? 5 : mfi;
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mfn_abs = mfn;
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#if !defined CONFIG_ARCH_MX1 && !defined CONFIG_ARCH_MX21
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if (mfn >= 0x200) {
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mfn |= 0xFFFFFE00;
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mfn_abs = -mfn;
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}
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#endif
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freq *= 2;
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freq /= pd + 1;
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ll = (unsigned long long)freq * mfn_abs;
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do_div(ll, mfd + 1);
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if (mfn < 0)
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ll = -ll;
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ll = (freq * mfi) + ll;
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return ll;
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}
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