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    Subject[PATCH 1/3] Clocklib: add generic framework for managing clocks.
    Provide a generic framework that platform may choose
    to support clocks api. In particular this provides
    platform-independant struct clk definition, a full
    implementation of clocks api and a set of functions
    for registering and unregistering clocks in a safe way.

    Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
    ---
    include/linux/clocklib.h | 58 ++++++++
    lib/Kconfig | 3 +
    lib/Makefile | 1 +
    lib/clocklib.c | 353 ++++++++++++++++++++++++++++++++++++++++++++++
    4 files changed, 415 insertions(+), 0 deletions(-)
    create mode 100644 include/linux/clocklib.h
    create mode 100644 lib/clocklib.c

    diff --git a/include/linux/clocklib.h b/include/linux/clocklib.h
    new file mode 100644
    index 0000000..cf2b41e
    --- /dev/null
    +++ b/include/linux/clocklib.h
    @@ -0,0 +1,58 @@
    +/*
    + * Copyright (C) 2008 Dmitry Baryshkov
    + *
    + * This file is released under the GPL v2.
    + */
    +
    +#ifndef CLKLIB_H
    +#define CLKLIB_H
    +
    +#include <linux/spinlock.h>
    +#include <linux/kref.h>
    +
    +struct clk;
    +
    +/**
    + * struct clk_ops - generic clock management operations
    + * @can_get: checks whether passed device can get this clock
    + * @set_parent: reconfigures the clock to use specified parent
    + * @set_mode: enable or disable specified clock
    + * @get_rate: obtain the current clock rate of a specified clock
    + * @set_rate: set the clock rate for a specified clock
    + * @round_rate: adjust a reate to the exact rate a clock can provide
    + *
    + * This structure specifies clock operations that are used to configure
    + * specific clock.
    + */
    +struct clk_ops {
    + int (*can_get)(struct clk *clk, struct device *dev);
    + int (*set_parent)(struct clk *clk, struct clk *parent);
    + int (*enable)(struct clk *clk);
    + void (*disable)(struct clk *clk);
    + unsigned long (*get_rate)(struct clk *clk);
    + long (*round_rate)(struct clk *clk, unsigned long hz, bool apply);
    +};
    +
    +
    +struct clk {
    + struct list_head node;
    + spinlock_t *lock;
    + struct kref ref;
    + int usage;
    +#ifdef CONFIG_DEBUG_FS
    + struct dentry *dir;
    + struct dentry *info;
    +#endif
    +
    + const char *name;
    + struct clk *parent;
    + struct clk_ops *ops;
    + void (*release)(struct clk *clk);
    +};
    +
    +int clk_register(struct clk *clk);
    +void clk_unregister(struct clk *clk);
    +int clks_register(struct clk **clk, size_t num);
    +void clks_unregister(struct clk **clk, size_t num);
    +
    +#endif
    diff --git a/lib/Kconfig b/lib/Kconfig
    index 8cc8e87..592f5e1 100644
    --- a/lib/Kconfig
    +++ b/lib/Kconfig
    @@ -13,6 +13,9 @@ config GENERIC_FIND_FIRST_BIT
    config GENERIC_FIND_NEXT_BIT
    def_bool n

    +config HAVE_CLOCKLIB
    + tristate
    +
    config CRC_CCITT
    tristate "CRC-CCITT functions"
    help
    diff --git a/lib/Makefile b/lib/Makefile
    index 74b0cfb..cee74e1 100644
    --- a/lib/Makefile
    +++ b/lib/Makefile
    @@ -37,6 +37,7 @@ obj-$(CONFIG_PLIST) += plist.o
    obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
    obj-$(CONFIG_DEBUG_LIST) += list_debug.o
    obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o
    +obj-$(CONFIG_HAVE_CLOCKLIB) += clocklib.o

    ifneq ($(CONFIG_HAVE_DEC_LOCK),y)
    lib-y += dec_and_lock.o
    diff --git a/lib/clocklib.c b/lib/clocklib.c
    new file mode 100644
    index 0000000..590a665
    --- /dev/null
    +++ b/lib/clocklib.c
    @@ -0,0 +1,353 @@
    +/*
    + * Generic clocks API implementation
    + *
    + * Copyright (c) 2008 Dmitry Baryshkov
    + *
    + * This file is released under the GPL v2.
    + */
    +#include <linux/kernel.h>
    +#include <linux/module.h>
    +#include <linux/clk.h>
    +#include <linux/clocklib.h>
    +#include <linux/spinlock.h>
    +
    +static LIST_HEAD(clocks);
    +static DEFINE_SPINLOCK(clocks_lock);
    +
    +#ifdef CONFIG_DEBUG_FS
    +#include <linux/debugfs.h>
    +#include <linux/seq_file.h>
    +static struct dentry *clkdir;
    +
    +static int clocklib_show(struct seq_file *s, void *data)
    +{
    + struct clk *clk = s->private;
    +
    + BUG_ON(!clk);
    +
    + seq_printf(s, "set_parent=%savailable\nusage=%d/%d\nrate=%10lu Hz\n",
    + clk->ops && clk->ops->set_parent ? "not " : "",
    + clk->usage, atomic_read(&clk->ref.refcount),
    + clk_get_rate(clk));
    +// if (clk->ops && clk->ops->format)
    +// clk->ops->format(clk, s);
    +
    + return 0;
    +}
    +
    +static int clocklib_open(struct inode *inode, struct file *file)
    +{
    + return single_open(file, clocklib_show, inode->i_private);
    +}
    +
    +static struct file_operations clocklib_operations = {
    + .open = clocklib_open,
    + .read = seq_read,
    + .llseek = seq_lseek,
    + .release = single_release,
    +};
    +
    +static int clk_debugfs_init(struct clk *clk)
    +{
    + struct dentry *dir;
    + struct dentry *info;
    +
    + if (!clkdir)
    + dump_stack();
    +
    + dir = debugfs_create_dir(clk->name,
    + clk->parent ? clk->parent->dir : clkdir);
    +
    + if (IS_ERR(dir))
    + return PTR_ERR(dir);
    +
    + info = debugfs_create_file("info", S_IFREG | S_IRUGO,
    + dir, clk, &clocklib_operations);
    +
    + if (IS_ERR(info)) {
    + debugfs_remove(dir);
    + return PTR_ERR(info);
    + }
    +
    + clk->dir = dir;
    + clk->info = info;
    +
    + return 0;
    +}
    +
    +static void clk_debugfs_clean(struct clk *clk)
    +{
    + if (clk->info)
    + debugfs_remove(clk->info);
    + clk->info = NULL;
    +
    + if (clk->dir)
    + debugfs_remove(clk->dir);
    + clk->dir = NULL;
    +}
    +
    +static void clk_debugfs_reparent(struct clk *clk, struct clk *old, struct clk *new)
    +{
    + struct dentry *oldd = old ? old->dir : clkdir;
    + struct dentry *newd = new ? new->dir : clkdir;
    + struct dentry *dir = debugfs_rename(oldd, clk->dir, newd, clk->name);
    +
    + if (IS_ERR(dir))
    + WARN_ON(1);
    + else
    + clk->dir = dir;
    +}
    +
    +static int __init clocklib_debugfs_init(void)
    +{
    + clkdir = debugfs_create_dir("clocks", NULL);
    + return 0;
    +}
    +core_initcall(clocklib_debugfs_init);
    +#else
    +#define clk_debugfs_init(clk) ({0;})
    +#define clk_debugfs_clean(clk) do {} while (0);
    +#define clk_debugfs_reparent(clk, old, new) do {} while (0);
    +#endif
    +
    +static int clk_can_get_def(struct clk *clk, struct device *dev)
    +{
    + return 1;
    +}
    +
    +static unsigned long clk_get_rate_def(struct clk *clk)
    +{
    + return 0;
    +}
    +
    +static long clk_round_rate_def(struct clk *clk, unsigned long hz, bool apply)
    +{
    + long rate = clk->ops->get_rate(clk);
    +
    + if (apply && hz != rate)
    + return -EINVAL;
    +
    + return rate;
    +}
    +
    +static void clk_release(struct kref *ref)
    +{
    + struct clk *clk = container_of(ref, struct clk, ref);
    +
    + BUG_ON(!clk->release);
    +
    + if (clk->parent)
    + kref_get(&clk->parent->ref);
    +
    + clk->release(clk);
    +}
    +EXPORT_SYMBOL(clk_round_rate);
    +
    +struct clk* clk_get_parent(struct clk *clk)
    +{
    + struct clk *parent;
    +
    + spin_lock(clk->lock);
    +
    + parent = clk->parent;
    + kref_get(&parent->ref);
    +
    + spin_unlock(clk->lock);
    +
    + return parent;
    +}
    +EXPORT_SYMBOL(clk_get_parent);
    +
    +int clk_set_parent(struct clk *clk, struct clk *parent)
    +{
    + int rc = -EINVAL;
    + struct clk *old;
    +
    + spin_lock(clk->lock);
    +
    + if (!clk->ops->set_parent)
    + goto out;
    +
    + old = clk->parent;
    +
    + rc = clk->ops->set_parent(clk, parent);
    + if (rc)
    + goto out;
    +
    + kref_get(&parent->ref);
    + clk->parent = parent;
    +
    + clk_debugfs_reparent(clk, old, parent);
    +
    + kref_put(&old->ref, clk_release);
    +
    +out:
    + spin_unlock(clk->lock);
    +
    + return rc;
    +}
    +EXPORT_SYMBOL(clk_set_parent);
    +
    +int clk_register(struct clk *clk)
    +{
    + int rc;
    +
    + BUG_ON(!clk->ops);
    + BUG_ON(!clk->ops->enable || !clk->ops->disable);
    +
    + if (!clk->ops->can_get)
    + clk->ops->can_get = clk_can_get_def;
    + if (!clk->ops->get_rate)
    + clk->ops->get_rate = clk_get_rate_def;
    + if (!clk->ops->round_rate)
    + clk->ops->round_rate = clk_round_rate_def;
    +
    + kref_init(&clk->ref);
    +
    + spin_lock(&clocks_lock);
    + if (clk->parent)
    + kref_get(&clk->parent->ref);
    + list_add_tail(&clk->node, &clocks);
    +
    + rc = clk_debugfs_init(clk);
    + if (rc) {
    + list_del(&clk->node);
    + kref_put(&clk->ref, clk_release);
    + }
    +
    + spin_unlock(&clocks_lock);
    +
    + return 0;
    +}
    +EXPORT_SYMBOL(clk_register);
    +
    +void clk_unregister(struct clk *clk)
    +{
    + spin_lock(&clocks_lock);
    + clk_debugfs_clean(clk);
    + list_del(&clk->node);
    + kref_put(&clk->ref, clk_release);
    + spin_unlock(&clocks_lock);
    +}
    +EXPORT_SYMBOL(clk_unregister);
    +
    +int clks_register(struct clk **clk, size_t num)
    +{
    + int i;
    + int rc;
    + for (i = 0; i < num; i++) {
    + rc = clk_register(clk[i]);
    + if (rc)
    + return rc;
    + }
    +
    + return 0;
    +}
    +EXPORT_SYMBOL(clks_register);
    +
    +void clks_unregister(struct clk **clk, size_t num)
    +{
    + int i;
    + for (i = 0; i < num; i++)
    + clk_unregister(clk[i]);
    +}
    +EXPORT_SYMBOL(clks_unregister);
    +
    +struct clk *clk_get(struct device *dev, const char *id)
    +{
    + struct clk *clk = NULL, *p;
    +
    + spin_lock(&clocks_lock);
    + list_for_each_entry(p, &clocks, node)
    + if (strcmp(id, p->name) == 0 && p->ops->can_get(p, dev)) {
    + clk = p;
    + kref_get(&clk->ref);
    + break;
    + }
    +
    + spin_unlock(&clocks_lock);
    +
    + return clk;
    +}
    +EXPORT_SYMBOL(clk_get);
    +
    +void clk_put(struct clk *clk)
    +{
    + kref_put(&clk->ref, clk_release);
    +}
    +EXPORT_SYMBOL(clk_put);
    +
    +int clk_enable(struct clk *clk)
    +{
    + int rc = 0;
    +
    + spin_lock(clk->lock);
    +
    + clk->usage++;
    + if (clk->usage == 1)
    + rc = clk->ops->enable(clk);
    +
    + if (rc)
    + clk->usage--;
    +
    + spin_unlock(clk->lock);
    +
    + return rc;
    +}
    +EXPORT_SYMBOL(clk_enable);
    +
    +void clk_disable(struct clk *clk)
    +{
    + spin_lock(clk->lock);
    +
    + WARN_ON(clk->usage <= 0);
    +
    + clk->usage--;
    + if (clk->usage == 0)
    + clk->ops->disable(clk);
    +
    + spin_unlock(clk->lock);
    +}
    +EXPORT_SYMBOL(clk_disable);
    +
    +unsigned long clk_get_rate(struct clk *clk)
    +{
    + unsigned long hz;
    +
    + spin_lock(clk->lock);
    +
    + hz = clk->ops->get_rate(clk);
    +
    + spin_unlock(clk->lock);
    +
    + return hz;
    +}
    +EXPORT_SYMBOL(clk_get_rate);
    +
    +int clk_set_rate(struct clk *clk, unsigned long hz)
    +{
    + long rc;
    +
    + spin_lock(clk->lock);
    +
    + rc = clk->ops->round_rate(clk, hz, 1);
    +
    + spin_unlock(clk->lock);
    +
    + return rc < 0 ? rc : 0;
    +}
    +EXPORT_SYMBOL(clk_set_rate);
    +
    +long clk_round_rate(struct clk *clk, unsigned long hz)
    +{
    + long rc;
    +
    + spin_lock(clk->lock);
    +
    + rc = clk->ops->round_rate(clk, hz, 0);
    +
    + spin_unlock(clk->lock);
    +
    + return rc;
    +}
    +
    --
    1.5.5.4

    --
    With best wishes
    Dmitry



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