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 <[EMAIL PROTECTED]>
---
include/linux/clklib.h | 85 ++++++++++++++
init/Kconfig | 7 +
kernel/Makefile | 1 +
kernel/clklib.c | 295 ++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 388 insertions(+), 0 deletions(-)
diff --git a/include/linux/clklib.h b/include/linux/clklib.h
new file mode 100644
index 0000000..4bd9b4a
--- /dev/null
+++ b/include/linux/clklib.h
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2008 Dmitry Baryshkov
+ *
+ * This file is released under the GPL v2.
+ */
+
+#ifndef CLKLIB_H
+#define CLKLIB_H
+
+#include <linux/list.h>
+
+struct clk {
+ struct list_head node;
+ struct clk *parent;
+
+ const char *name;
+ struct module *owner;
+
+ int users;
+ unsigned long rate;
+ int delay;
+
+ int (*can_get) (struct clk *, struct device *);
+ int (*set_parent) (struct clk *, struct clk *);
+ int (*enable) (struct clk *);
+ void (*disable) (struct clk *);
+ unsigned long (*getrate) (struct clk*);
+ int (*setrate) (struct clk *, unsigned long);
+ long (*roundrate) (struct clk *, unsigned long);
+
+ void *priv;
+};
+
+int clk_register(struct clk *clk);
+void clk_unregister(struct clk *clk);
+static void __maybe_unused clks_register(struct clk *clks, size_t num)
+{
+ int i;
+ for (i = 0; i < num; i++) {
+ clk_register(&clks[i]);
+ }
+}
+
+
+int clk_alloc_function(const char *parent, struct clk *clk);
+
+struct clk_function {
+ const char *parent;
+ struct clk *clk;
+};
+
+#define CLK_FUNC(_clock, _function, _can_get, _data, _format) \
+ { \
+ .parent = _clock, \
+ .clk = &(struct clk) { \
+ .name= _function, \
+ .owner = THIS_MODULE, \
+ .can_get = _can_get, \
+ .priv = _data, \
+ .format = _format, \
+ }, \
+ }
+
+static int __maybe_unused clk_alloc_functions(
+ struct clk_function *funcs,
+ int num)
+{
+ int i;
+ int rc;
+
+ for (i = 0; i < num; i++) {
+ rc = clk_alloc_function(funcs[i].parent, funcs[i].clk);
+
+ if (rc) {
+ printk(KERN_ERR "Error allocating %s.%s function.\n",
+ funcs[i].parent,
+ funcs[i].clk->name);
+ return rc;
+ }
+ }
+
+ return 0;
+}
+
+#endif
diff --git a/init/Kconfig b/init/Kconfig
index dcc96a8..18d53c1 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -444,6 +444,13 @@ config CC_OPTIMIZE_FOR_SIZE
config SYSCTL
bool
+config HAVE_CLOCK_LIB
+ bool
+ help
+ Platforms select clocklib if they use this infrastructure
+ for managing their clocks both built into SoC and provided
+ by external devices.
+
menuconfig EMBEDDED
bool "Configure standard kernel features (for small systems)"
help
diff --git a/kernel/Makefile b/kernel/Makefile
index 8885627..0bc929a 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o
obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o
obj-$(CONFIG_MARKERS) += marker.o
obj-$(CONFIG_LATENCYTOP) += latencytop.o
+obj-$(CONFIG_HAVE_CLOCK_LIB) += clklib.o
ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
# According to Alan Modra <[EMAIL PROTECTED]>, the -fno-omit-frame-pointer is
diff --git a/kernel/clklib.c b/kernel/clklib.c
new file mode 100644
index 0000000..203af3d
--- /dev/null
+++ b/kernel/clklib.c
@@ -0,0 +1,295 @@
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/clklib.h>
+#include <linux/spinlock.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+static LIST_HEAD(clocks);
+static DEFINE_SPINLOCK(clocks_lock);
+
+static int __clk_register(struct clk *clk)
+{
+ if (clk->parent &&
+ !try_module_get(clk->parent->owner))
+ return -EINVAL;
+
+ list_add_tail(&clk->node, &clocks);
+
+ return 0;
+}
+
+int clk_register(struct clk *clk)
+{
+ unsigned long flags;
+ int rc;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ rc = __clk_register(clk);
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return rc;
+}
+EXPORT_SYMBOL(clk_register);
+
+void clk_unregister(struct clk *clk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+ list_del(&clk->node);
+ if (clk->parent)
+ module_put(clk->parent->owner);
+ spin_unlock_irqrestore(&clocks_lock, flags);
+}
+EXPORT_SYMBOL(clk_unregister);
+
+struct clk *clk_get(struct device *dev, const char *id)
+{
+ struct clk *p, *clk = ERR_PTR(-ENOENT);
+ unsigned long flags;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ list_for_each_entry(p, &clocks, node) {
+ if (strcmp(id, p->name) == 0 &&
+ (!p->can_get || p->can_get(p, dev)) &&
+ try_module_get(p->owner)) {
+ clk = p;
+ break;
+ }
+ }
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return clk;
+}
+EXPORT_SYMBOL(clk_get);
+
+void clk_put(struct clk *clk)
+{
+ unsigned long flags;
+
+ if (!clk || IS_ERR(clk))
+ return;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ module_put(clk->owner);
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+}
+EXPORT_SYMBOL(clk_put);
+
+int clk_set_parent(struct clk *clk, struct clk *parent)
+{
+ int rc;
+ unsigned long flags;
+
+ if (!clk || IS_ERR(clk))
+ return -EINVAL;
+
+ if (!clk->set_parent)
+ return -EINVAL;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ rc = clk->set_parent(clk, parent);
+ if (!rc)
+ clk->parent = parent;
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return rc;
+}
+EXPORT_SYMBOL(clk_set_parent);
+
+static int __clk_enable(struct clk *clk)
+{
+ int rc = 0;
+
+ if (clk->parent) {
+ rc = __clk_enable(clk->parent);
+
+ if (rc)
+ return rc;
+ }
+
+ if (clk->users++ == 0)
+ if (clk->enable)
+ rc = clk->enable(clk);
+
+ if (clk->delay)
+ udelay(clk->delay);
+
+ return rc;
+}
+
+int clk_enable(struct clk *clk)
+{
+ unsigned long flags;
+ int rc;
+
+ if (!clk || IS_ERR(clk))
+ return -EINVAL;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ rc = __clk_enable(clk);
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return rc;
+}
+EXPORT_SYMBOL(clk_enable);
+
+static void __clk_disable(struct clk *clk)
+{
+ if (clk->users <= 0) {
+ WARN_ON(1);
+ return;
+ }
+
+ if (--clk->users == 0)
+ if (clk->disable)
+ clk->disable(clk);
+
+ if (clk->parent)
+ __clk_disable(clk->parent);
+}
+
+void clk_disable(struct clk *clk)
+{
+ unsigned long flags;
+
+ if (!clk || IS_ERR(clk))
+ return;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ __clk_disable(clk);
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+}
+EXPORT_SYMBOL(clk_disable);
+
+static unsigned long __clk_get_rate(struct clk *clk)
+{
+ unsigned long rate = 0;
+
+ for (;;) {
+ if (rate || !clk)
+ return rate;
+
+ if (clk->getrate)
+ rate = clk->getrate(clk);
+ else if (clk->rate)
+ rate = clk->rate;
+ else
+ clk = clk->parent;
+ }
+}
+
+unsigned long clk_get_rate(struct clk *clk)
+{
+ unsigned long rate = 0;
+ unsigned long flags;
+
+ if (!clk || IS_ERR(clk))
+ return -EINVAL;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ rate = __clk_get_rate(clk);
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return rate;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
+long clk_round_rate(struct clk *clk, unsigned long rate)
+{
+ long res;
+ unsigned long flags;
+
+ if (!clk || IS_ERR(clk))
+ return -EINVAL;
+
+ if (!clk->roundrate)
+ return -EINVAL;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ res = clk->roundrate(clk, rate);
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return res;
+}
+EXPORT_SYMBOL(clk_round_rate);
+
+int clk_set_rate(struct clk *clk, unsigned long rate)
+{
+ int rc;
+ unsigned long flags;
+
+ if (!clk || IS_ERR(clk))
+ return -EINVAL;
+
+ if (!clk->setrate)
+ return -EINVAL;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ rc = clk->setrate(clk, rate);
+
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return rc;
+}
+EXPORT_SYMBOL(clk_set_rate);
+
+int clk_alloc_function(const char *parent, struct clk *clk)
+{
+ int rc = 0;
+ unsigned long flags;
+ struct clk *pclk;
+ bool found = false;
+
+ spin_lock_irqsave(&clocks_lock, flags);
+
+ list_for_each_entry(pclk, &clocks, node) {
+ if (strcmp(parent, pclk->name) == 0 &&
+ try_module_get(pclk->owner)) {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ rc = -ENODEV;
+ goto out;
+ }
+
+ clk->parent = pclk;
+
+ __clk_register(clk);
+ /*
+ * We locked parent owner during search
+ * and also in __clk_register. Free one reference
+ */
+ module_put(pclk->owner);
+
+out:
+ if (rc) {
+ kfree(clk);
+ }
+ spin_unlock_irqrestore(&clocks_lock, flags);
+
+ return rc;
+}
+EXPORT_SYMBOL(clk_alloc_function);
--
1.5.3.8
--
With best wishes
Dmitry
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