clock.c

Go to the documentation of this file.

/*
 * Clock management for AT32AP CPUs
 *
 * Copyright (C) 2006 Atmel Corporation
 *
 * Based on arch/arm/mach-at91/clock.c
 *   Copyright (C) 2005 David Brownell
 *   Copyright (C) 2005 Ivan Kokshaysky
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/list.h>

#include <mach/chip.h>

#include "clock.h"

/* at32 clock list */
static LIST_HEAD(at32_clock_list);

static DEFINE_SPINLOCK(clk_lock);
static DEFINE_SPINLOCK(clk_list_lock);

void at32_clk_register(struct clk *clk)
{
    spin_lock(&clk_list_lock);
    /* add the new item to the end of the list */
    list_add_tail(&clk->list, &at32_clock_list);
    spin_unlock(&clk_list_lock);
}

static struct clk *__clk_get(struct device *dev, const char *id)
{
    struct clk *clk;

    list_for_each_entry(clk, &at32_clock_list, list) {
        if (clk->dev == dev && strcmp(id, clk->name) == 0) {
            return clk;
        }
    }

    return ERR_PTR(-ENOENT);
}

struct clk *clk_get(struct device *dev, const char *id)
{
    struct clk *clk;

    spin_lock(&clk_list_lock);
    clk = __clk_get(dev, id);
    spin_unlock(&clk_list_lock);

    return clk;
}

EXPORT_SYMBOL(clk_get);

void clk_put(struct clk *clk)
{
    /* clocks are static for now, we can't free them */
}
EXPORT_SYMBOL(clk_put);

static void __clk_enable(struct clk *clk)
{
    if (clk->parent)
        __clk_enable(clk->parent);
    if (clk->users++ == 0 && clk->mode)
        clk->mode(clk, 1);
}

int clk_enable(struct clk *clk)
{
    unsigned long flags;

    spin_lock_irqsave(&clk_lock, flags);
    __clk_enable(clk);
    spin_unlock_irqrestore(&clk_lock, flags);

    return 0;
}
EXPORT_SYMBOL(clk_enable);

static void __clk_disable(struct clk *clk)
{
    if (clk->users == 0) {
        printk(KERN_ERR "%s: mismatched disable\n", clk->name);
        WARN_ON(1);
        return;
    }

    if (--clk->users == 0 && clk->mode)
        clk->mode(clk, 0);
    if (clk->parent)
        __clk_disable(clk->parent);
}

void clk_disable(struct clk *clk)
{
    unsigned long flags;

    spin_lock_irqsave(&clk_lock, flags);
    __clk_disable(clk);
    spin_unlock_irqrestore(&clk_lock, flags);
}
EXPORT_SYMBOL(clk_disable);

unsigned long clk_get_rate(struct clk *clk)
{
    unsigned long flags;
    unsigned long rate;

    spin_lock_irqsave(&clk_lock, flags);
    rate = clk->get_rate(clk);
    spin_unlock_irqrestore(&clk_lock, flags);

    return rate;
}
EXPORT_SYMBOL(clk_get_rate);

long clk_round_rate(struct clk *clk, unsigned long rate)
{
    unsigned long flags, actual_rate;

    if (!clk->set_rate)
        return -ENOSYS;

    spin_lock_irqsave(&clk_lock, flags);
    actual_rate = clk->set_rate(clk, rate, 0);
    spin_unlock_irqrestore(&clk_lock, flags);

    return actual_rate;
}
EXPORT_SYMBOL(clk_round_rate);

int clk_set_rate(struct clk *clk, unsigned long rate)
{
    unsigned long flags;
    long ret;

    if (!clk->set_rate)
        return -ENOSYS;

    spin_lock_irqsave(&clk_lock, flags);
    ret = clk->set_rate(clk, rate, 1);
    spin_unlock_irqrestore(&clk_lock, flags);

    return (ret < 0) ? ret : 0;
}
EXPORT_SYMBOL(clk_set_rate);

int clk_set_parent(struct clk *clk, struct clk *parent)
{
    unsigned long flags;
    int ret;

    if (!clk->set_parent)
        return -ENOSYS;

    spin_lock_irqsave(&clk_lock, flags);
    ret = clk->set_parent(clk, parent);
    spin_unlock_irqrestore(&clk_lock, flags);

    return ret;
}
EXPORT_SYMBOL(clk_set_parent);

struct clk *clk_get_parent(struct clk *clk)
{
    return clk->parent;
}
EXPORT_SYMBOL(clk_get_parent);



#ifdef CONFIG_DEBUG_FS

/* /sys/kernel/debug/at32ap_clk */

#include <linux/io.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include "pm.h"


#define NEST_DELTA  2
#define NEST_MAX    6

struct clkinf {
    struct seq_file *s;
    unsigned    nest;
};

static void
dump_clock(struct clk *parent, struct clkinf *r)
{
    unsigned    nest = r->nest;
    char        buf[16 + NEST_MAX];
    struct clk  *clk;
    unsigned    i;

    /* skip clocks coupled to devices that aren't registered */
    if (parent->dev && !dev_name(parent->dev) && !parent->users)
        return;

    /* <nest spaces> name <pad to end> */
    memset(buf, ' ', sizeof(buf) - 1);
    buf[sizeof(buf) - 1] = 0;
    i = strlen(parent->name);
    memcpy(buf + nest, parent->name,
            min(i, (unsigned)(sizeof(buf) - 1 - nest)));

    seq_printf(r->s, "%s%c users=%2d %-3s %9ld Hz",
        buf, parent->set_parent ? '*' : ' ',
        parent->users,
        parent->users ? "on" : "off",   /* NOTE: not-paranoid!! */
        clk_get_rate(parent));
    if (parent->dev)
        seq_printf(r->s, ", for %s", dev_name(parent->dev));
    seq_printf(r->s, "\n");

    /* cost of this scan is small, but not linear... */
    r->nest = nest + NEST_DELTA;

    list_for_each_entry(clk, &at32_clock_list, list) {
        if (clk->parent == parent)
            dump_clock(clk, r);
    }
    r->nest = nest;
}

static int clk_show(struct seq_file *s, void *unused)
{
    struct clkinf   r;
    int     i;
    struct clk  *clk;

    /* show all the power manager registers */
    seq_printf(s, "MCCTRL  = %8x\n", pm_readl(MCCTRL));
    seq_printf(s, "CKSEL   = %8x\n", pm_readl(CKSEL));
    seq_printf(s, "CPUMASK = %8x\n", pm_readl(CPU_MASK));
    seq_printf(s, "HSBMASK = %8x\n", pm_readl(HSB_MASK));
    seq_printf(s, "PBAMASK = %8x\n", pm_readl(PBA_MASK));
    seq_printf(s, "PBBMASK = %8x\n", pm_readl(PBB_MASK));
    seq_printf(s, "PLL0    = %8x\n", pm_readl(PLL0));
    seq_printf(s, "PLL1    = %8x\n", pm_readl(PLL1));
    seq_printf(s, "IMR     = %8x\n", pm_readl(IMR));
    for (i = 0; i < 8; i++) {
        if (i == 5)
            continue;
        seq_printf(s, "GCCTRL%d = %8x\n", i, pm_readl(GCCTRL(i)));
    }

    seq_printf(s, "\n");

    r.s = s;
    r.nest = 0;
    /* protected from changes on the list while dumping */
    spin_lock(&clk_list_lock);

    /* show clock tree as derived from the three oscillators */
    clk = __clk_get(NULL, "osc32k");
    dump_clock(clk, &r);
    clk_put(clk);

    clk = __clk_get(NULL, "osc0");
    dump_clock(clk, &r);
    clk_put(clk);

    clk = __clk_get(NULL, "osc1");
    dump_clock(clk, &r);
    clk_put(clk);

    spin_unlock(&clk_list_lock);

    return 0;
}

static int clk_open(struct inode *inode, struct file *file)
{
    return single_open(file, clk_show, NULL);
}

static const struct file_operations clk_operations = {
    .open       = clk_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int __init clk_debugfs_init(void)
{
    (void) debugfs_create_file("at32ap_clk", S_IFREG | S_IRUGO,
            NULL, NULL, &clk_operations);

    return 0;
}
postcore_initcall(clk_debugfs_init);

#endif