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-rw-r--r--Documentation/clk.txt4
-rw-r--r--drivers/clk/clk.c100
-rw-r--r--include/linux/clk-private.h1
-rw-r--r--include/linux/clk-provider.h11
-rw-r--r--include/linux/clk.h17
5 files changed, 126 insertions, 7 deletions
diff --git a/Documentation/clk.txt b/Documentation/clk.txt
index 3aeb5c440442..eb20198783cd 100644
--- a/Documentation/clk.txt
+++ b/Documentation/clk.txt
@@ -77,6 +77,8 @@ the operations defined in clk.h:
int (*set_parent)(struct clk_hw *hw, u8 index);
u8 (*get_parent)(struct clk_hw *hw);
int (*set_rate)(struct clk_hw *hw, unsigned long);
+ unsigned long (*recalc_accuracy)(struct clk_hw *hw,
+ unsigned long parent_accuracy);
void (*init)(struct clk_hw *hw);
};
@@ -202,6 +204,8 @@ optional or must be evaluated on a case-by-case basis.
.set_parent | | | n | y | n |
.get_parent | | | n | y | n |
| | | | | |
+.recalc_accuracy| | | | | |
+ | | | | | |
.init | | | | | |
-----------------------------------------------------------
[1] either one of round_rate or determine_rate is required.
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 83127363ad4c..fbe08f618d59 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -104,10 +104,11 @@ static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
if (!c)
return;
- seq_printf(s, "%*s%-*s %-11d %-12d %-10lu",
+ seq_printf(s, "%*s%-*s %-11d %-12d %-10lu %-11lu",
level * 3 + 1, "",
30 - level * 3, c->name,
- c->enable_count, c->prepare_count, clk_get_rate(c));
+ c->enable_count, c->prepare_count, clk_get_rate(c),
+ clk_get_accuracy(c));
seq_printf(s, "\n");
}
@@ -129,8 +130,8 @@ static int clk_summary_show(struct seq_file *s, void *data)
{
struct clk *c;
- seq_printf(s, " clock enable_cnt prepare_cnt rate\n");
- seq_printf(s, "---------------------------------------------------------------------\n");
+ seq_printf(s, " clock enable_cnt prepare_cnt rate accuracy\n");
+ seq_printf(s, "---------------------------------------------------------------------------------\n");
clk_prepare_lock();
@@ -167,6 +168,7 @@ static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
seq_printf(s, "\"enable_count\": %d,", c->enable_count);
seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
+ seq_printf(s, "\"accuracy\": %lu", clk_get_accuracy(c));
}
static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
@@ -248,6 +250,11 @@ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
if (!d)
goto err_out;
+ d = debugfs_create_u32("clk_accuracy", S_IRUGO, clk->dentry,
+ (u32 *)&clk->accuracy);
+ if (!d)
+ goto err_out;
+
d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
(u32 *)&clk->flags);
if (!d)
@@ -603,6 +610,14 @@ out:
return ret;
}
+unsigned long __clk_get_accuracy(struct clk *clk)
+{
+ if (!clk)
+ return 0;
+
+ return clk->accuracy;
+}
+
unsigned long __clk_get_flags(struct clk *clk)
{
return !clk ? 0 : clk->flags;
@@ -1017,6 +1032,59 @@ static int __clk_notify(struct clk *clk, unsigned long msg,
}
/**
+ * __clk_recalc_accuracies
+ * @clk: first clk in the subtree
+ *
+ * Walks the subtree of clks starting with clk and recalculates accuracies as
+ * it goes. Note that if a clk does not implement the .recalc_accuracy
+ * callback then it is assumed that the clock will take on the accuracy of it's
+ * parent.
+ *
+ * Caller must hold prepare_lock.
+ */
+static void __clk_recalc_accuracies(struct clk *clk)
+{
+ unsigned long parent_accuracy = 0;
+ struct clk *child;
+
+ if (clk->parent)
+ parent_accuracy = clk->parent->accuracy;
+
+ if (clk->ops->recalc_accuracy)
+ clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
+ parent_accuracy);
+ else
+ clk->accuracy = parent_accuracy;
+
+ hlist_for_each_entry(child, &clk->children, child_node)
+ __clk_recalc_accuracies(child);
+}
+
+/**
+ * clk_get_accuracy - return the accuracy of clk
+ * @clk: the clk whose accuracy is being returned
+ *
+ * Simply returns the cached accuracy of the clk, unless
+ * CLK_GET_ACCURACY_NOCACHE flag is set, which means a recalc_rate will be
+ * issued.
+ * If clk is NULL then returns 0.
+ */
+long clk_get_accuracy(struct clk *clk)
+{
+ unsigned long accuracy;
+
+ clk_prepare_lock();
+ if (clk && (clk->flags & CLK_GET_ACCURACY_NOCACHE))
+ __clk_recalc_accuracies(clk);
+
+ accuracy = __clk_get_accuracy(clk);
+ clk_prepare_unlock();
+
+ return accuracy;
+}
+EXPORT_SYMBOL_GPL(clk_get_accuracy);
+
+/**
* __clk_recalc_rates
* @clk: first clk in the subtree
* @msg: notification type (see include/linux/clk.h)
@@ -1552,6 +1620,7 @@ void __clk_reparent(struct clk *clk, struct clk *new_parent)
{
clk_reparent(clk, new_parent);
clk_debug_reparent(clk, new_parent);
+ __clk_recalc_accuracies(clk);
__clk_recalc_rates(clk, POST_RATE_CHANGE);
}
@@ -1622,11 +1691,13 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
/* do the re-parent */
ret = __clk_set_parent(clk, parent, p_index);
- /* propagate rate recalculation accordingly */
- if (ret)
+ /* propagate rate an accuracy recalculation accordingly */
+ if (ret) {
__clk_recalc_rates(clk, ABORT_RATE_CHANGE);
- else
+ } else {
__clk_recalc_rates(clk, POST_RATE_CHANGE);
+ __clk_recalc_accuracies(clk);
+ }
out:
clk_prepare_unlock();
@@ -1731,6 +1802,21 @@ int __clk_init(struct device *dev, struct clk *clk)
hlist_add_head(&clk->child_node, &clk_orphan_list);
/*
+ * Set clk's accuracy. The preferred method is to use
+ * .recalc_accuracy. For simple clocks and lazy developers the default
+ * fallback is to use the parent's accuracy. If a clock doesn't have a
+ * parent (or is orphaned) then accuracy is set to zero (perfect
+ * clock).
+ */
+ if (clk->ops->recalc_accuracy)
+ clk->accuracy = clk->ops->recalc_accuracy(clk->hw,
+ __clk_get_accuracy(clk->parent));
+ else if (clk->parent)
+ clk->accuracy = clk->parent->accuracy;
+ else
+ clk->accuracy = 0;
+
+ /*
* Set clk's rate. The preferred method is to use .recalc_rate. For
* simple clocks and lazy developers the default fallback is to use the
* parent's rate. If a clock doesn't have a parent (or is orphaned)
diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index 8138c94409f3..accb517e77e9 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -41,6 +41,7 @@ struct clk {
unsigned long flags;
unsigned int enable_count;
unsigned int prepare_count;
+ unsigned long accuracy;
struct hlist_head children;
struct hlist_node child_node;
unsigned int notifier_count;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 7e59253b8603..16d182c28ce6 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -29,6 +29,7 @@
#define CLK_IS_BASIC BIT(5) /* Basic clk, can't do a to_clk_foo() */
#define CLK_GET_RATE_NOCACHE BIT(6) /* do not use the cached clk rate */
#define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate change */
+#define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */
struct clk_hw;
@@ -108,6 +109,13 @@ struct clk_hw;
* which is likely helpful for most .set_rate implementation.
* Returns 0 on success, -EERROR otherwise.
*
+ * @recalc_accuracy: Recalculate the accuracy of this clock. The clock accuracy
+ * is expressed in ppb (parts per billion). The parent accuracy is
+ * an input parameter.
+ * Returns the calculated accuracy. Optional - if this op is not
+ * set then clock accuracy will be initialized to parent accuracy
+ * or 0 (perfect clock) if clock has no parent.
+ *
* The clk_enable/clk_disable and clk_prepare/clk_unprepare pairs allow
* implementations to split any work between atomic (enable) and sleepable
* (prepare) contexts. If enabling a clock requires code that might sleep,
@@ -139,6 +147,8 @@ struct clk_ops {
u8 (*get_parent)(struct clk_hw *hw);
int (*set_rate)(struct clk_hw *hw, unsigned long,
unsigned long);
+ unsigned long (*recalc_accuracy)(struct clk_hw *hw,
+ unsigned long parent_accuracy);
void (*init)(struct clk_hw *hw);
};
@@ -433,6 +443,7 @@ struct clk *clk_get_parent_by_index(struct clk *clk, u8 index);
unsigned int __clk_get_enable_count(struct clk *clk);
unsigned int __clk_get_prepare_count(struct clk *clk);
unsigned long __clk_get_rate(struct clk *clk);
+unsigned long __clk_get_accuracy(struct clk *clk);
unsigned long __clk_get_flags(struct clk *clk);
bool __clk_is_prepared(struct clk *clk);
bool __clk_is_enabled(struct clk *clk);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 9a6d04524b1a..0dd91148165e 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -82,6 +82,23 @@ int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
+/**
+ * clk_get_accuracy - obtain the clock accuracy in ppb (parts per billion)
+ * for a clock source.
+ * @clk: clock source
+ *
+ * This gets the clock source accuracy expressed in ppb.
+ * A perfect clock returns 0.
+ */
+long clk_get_accuracy(struct clk *clk);
+
+#else
+
+static inline long clk_get_accuracy(struct clk *clk)
+{
+ return -ENOTSUPP;
+}
+
#endif
/**