path: root/arch/arm/mach-u300/clock.c

/*
 *
 * arch/arm/mach-u300/clock.c
 *
 *
 * Copyright (C) 2007-2009 ST-Ericsson AB
 * License terms: GNU General Public License (GPL) version 2
 * Define clocks in the app platform.
 * Author: Linus Walleij <linus.walleij@stericsson.com>
 * Author: Jonas Aaberg <jonas.aberg@stericsson.com>
 *
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/clk.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/io.h>
#include <linux/seq_file.h>

#include <asm/clkdev.h>
#include <mach/hardware.h>
#include <mach/syscon.h>

#include "clock.h"

/*
 * TODO:
 * - move all handling of the CCR register into this file and create
 *   a spinlock for the CCR register
 * - switch to the clkdevice lookup mechanism that maps clocks to
 *   device ID:s instead when it becomes available in kernel 2.6.29.
 * - implement rate get/set for all clocks that need it.
 */

/*
 * Syscon clock I/O registers lock so clock requests don't collide
 * NOTE: this is a local lock only used to lock access to clock and
 * reset registers in syscon.
 */
static DEFINE_SPINLOCK(syscon_clkreg_lock);
static DEFINE_SPINLOCK(syscon_resetreg_lock);

/*
 * The clocking hierarchy currently looks like this.
 * NOTE: the idea is NOT to show how the clocks are routed on the chip!
 * The ideas is to show dependencies, so a clock higher up in the
 * hierarchy has to be on in order for another clock to be on. Now,
 * both CPU and DMA can actually be on top of the hierarchy, and that
 * is not modeled currently. Instead we have the backbone AMBA bus on
 * top. This bus cannot be programmed in any way but conceptually it
 * needs to be active for the bridges and device