1 files changed, 124 insertions, 51 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b76fa69b44cb..4896ae9e23da 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -100,6 +100,8 @@ static void clk_enable_unlock(unsigned long flags)
 
 static struct dentry *rootdir;
 static int inited = 0;
+static DEFINE_MUTEX(clk_debug_lock);
+static HLIST_HEAD(clk_debug_list);
 
 static struct hlist_head *all_lists[] = {
 	&clk_root_list,
@@ -117,11 +119,11 @@ 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 %11lu %10lu\n",
+	seq_printf(s, "%*s%-*s %11d %12d %11lu %10lu %-3d\n",
 		   level * 3 + 1, "",
 		   30 - level * 3, c->name,
 		   c->enable_count, c->prepare_count, clk_get_rate(c),
-		   clk_get_accuracy(c));
+		   clk_get_accuracy(c), clk_get_phase(c));
 }
 
 static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
@@ -143,8 +145,8 @@ static int clk_summary_show(struct seq_file *s, void *data)
 	struct clk *c;
 	struct hlist_head **lists = (struct hlist_head **)s->private;
 
-	seq_puts(s, "   clock                         enable_cnt  prepare_cnt        rate   accuracy\n");
-	seq_puts(s, "--------------------------------------------------------------------------------\n");
+	seq_puts(s, "   clock                         enable_cnt  prepare_cnt        rate   accuracy   phase\n");
+	seq_puts(s, "----------------------------------------------------------------------------------------\n");
 
 	clk_prepare_lock();
 
@@ -180,6 +182,7 @@ static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
 	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));
+	seq_printf(s, "\"phase\": %d", clk_get_phase(c));
 }
 
 static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
@@ -264,6 +267,11 @@ static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
 	if (!d)
 		goto err_out;
 
+	d = debugfs_create_u32("clk_phase", S_IRUGO, clk->dentry,
+			(u32 *)&clk->phase);
+	if (!d)
+		goto err_out;
+
 	d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
 			(u32 *)&clk->flags);
 	if (!d)
@@ -300,28 +308,6 @@ out:
 	return ret;
 }
 
-/* caller must hold prepare_lock */
-static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
-{
-	struct clk *child;
-	int ret = -EINVAL;;
-
-	if (!clk || !pdentry)
-		goto out;
-
-	ret = clk_debug_create_one(clk, pdentry);
-
-	if (ret)
-		goto out;
-
-	hlist_for_each_entry(child, &clk->children, child_node)
-		clk_debug_create_subtree(child, pdentry);
-
-	ret = 0;
-out:
-	return ret;
-}
-
 /**
  * clk_debug_register - add a clk node to the debugfs clk tree
  * @clk: the clk being added to the debugfs clk tree
@@ -329,20 +315,21 @@ out:
  * Dynamically adds a clk to the debugfs clk tree if debugfs has been
  * initialized.  Otherwise it bails out early since the debugfs clk tree
  * will be created lazily by clk_debug_init as part of a late_initcall.
- *
- * Caller must hold prepare_lock.  Only clk_init calls this function (so
- * far) so this is taken care.
  */
 static int clk_debug_register(struct clk *clk)
 {
 	int ret = 0;
 
+	mutex_lock(&clk_debug_lock);
+	hlist_add_head(&clk->debug_node, &clk_debug_list);
+
 	if (!inited)
-		goto out;
+		goto unlock;
 
-	ret = clk_debug_create_subtree(clk, rootdir);
+	ret = clk_debug_create_one(clk, rootdir);
+unlock:
+	mutex_unlock(&clk_debug_lock);
 
-out:
 	return ret;
 }
 
@@ -353,12 +340,18 @@ out:
  * Dynamically removes a clk and all it's children clk nodes from the
  * debugfs clk tree if clk->dentry points to debugfs created by
  * clk_debug_register in __clk_init.
- *
- * Caller must hold prepare_lock.
  */
 static void clk_debug_unregister(struct clk *clk)
 {
+	mutex_lock(&clk_debug_lock);
+	if (!clk->dentry)
+		goto out;
+
+	hlist_del_init(&clk->debug_node);
 	debugfs_remove_recursive(clk->dentry);
+	clk->dentry = NULL;
+out:
+	mutex_unlock(&clk_debug_lock);
 }
 
 struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
@@ -415,17 +408,12 @@ static int __init clk_debug_init(void)
 	if (!d)
 		return -ENOMEM;
 
-	clk_prepare_lock();
-
-	hlist_for_each_entry(clk, &clk_root_list, child_node)
-		clk_debug_create_subtree(clk, rootdir);
-
-	hlist_for_each_entry(clk, &clk_orphan_list, child_node)
-		clk_debug_create_subtree(clk, rootdir);
+	mutex_lock(&clk_debug_lock);
+	hlist_for_each_entry(clk, &clk_debug_list, debug_node)
+		clk_debug_create_one(clk, rootdir);
 
 	inited = 1;
-
-	clk_prepare_unlock();
+	mutex_unlock(&clk_debug_lock);
 
 	return 0;
 }
@@ -1467,6 +1455,7 @@ static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long even
 static void clk_change_rate(struct clk *clk)
 {
 	struct clk *child;
+	struct hlist_node *tmp;
 	unsigned long old_rate;
 	unsigned long best_parent_rate = 0;
 	bool skip_set_rate = false;
@@ -1502,7 +1491,11 @@ static void clk_change_rate(struct clk *clk)
 	if (clk->notifier_count && old_rate != clk->rate)
 		__clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
 
-	hlist_for_each_entry(child, &clk->children, child_node) {
+	/*
+	 * Use safe iteration, as change_rate can actually swap parents
+	 * for certain clock types.
+	 */
+	hlist_for_each_entry_safe(child, tmp, &clk->children, child_node) {
 		/* Skip children who will be reparented to another clock */
 		if (child->new_parent && child->new_parent != clk)
 			continue;
@@ -1739,6 +1732,77 @@ out:
 EXPORT_SYMBOL_GPL(clk_set_parent);
 
 /**
+ * clk_set_phase - adjust the phase shift of a clock signal
+ * @clk: clock signal source
+ * @degrees: number of degrees the signal is shifted
+ *
+ * Shifts the phase of a clock signal by the specified
+ * degrees. Returns 0 on success, -EERROR otherwise.
+ *
+ * This function makes no distinction about the input or reference
+ * signal that we adjust the clock signal phase against. For example
+ * phase locked-loop clock signal generators we may shift phase with
+ * respect to feedback clock signal input, but for other cases the
+ * clock phase may be shifted with respect to some other, unspecified
+ * signal.
+ *
+ * Additionally the concept of phase shift does not propagate through
+ * the clock tree hierarchy, which sets it apart from clock rates and
+ * clock accuracy. A parent clock phase attribute does not have an
+ * impact on the phase attribute of a child clock.
+ */
+int clk_set_phase(struct clk *clk, int degrees)
+{
+	int ret = 0;
+
+	if (!clk)
+		goto out;
+
+	/* sanity check degrees */
+	degrees %= 360;
+	if (degrees < 0)
+		degrees += 360;
+
+	clk_prepare_lock();
+
+	if (!clk->ops->set_phase)
+		goto out_unlock;
+
+	ret = clk->ops->set_phase(clk->hw, degrees);
+
+	if (!ret)
+		clk->phase = degrees;
+
+out_unlock:
+	clk_prepare_unlock();
+
+out:
+	return ret;
+}
+
+/**
+ * clk_get_phase - return the phase shift of a clock signal
+ * @clk: clock signal source
+ *
+ * Returns the phase shift of a clock node in degrees, otherwise returns
+ * -EERROR.
+ */
+int clk_get_phase(struct clk *clk)
+{
+	int ret = 0;
+
+	if (!clk)
+		goto out;
+
+	clk_prepare_lock();
+	ret = clk->phase;
+	clk_prepare_unlock();
+
+out:
+	return ret;
+}
+
+/**
  * __clk_init - initialize the data structures in a struct clk
  * @dev:	device initializing this clk, placeholder for now
  * @clk:	clk being initialized
@@ -1857,6 +1921,16 @@ int __clk_init(struct device *dev, struct clk *clk)
 		clk->accuracy = 0;
 
 	/*
+	 * Set clk's phase.
+	 * Since a phase is by definition relative to its parent, just
+	 * query the current clock phase, or just assume it's in phase.
+	 */
+	if (clk->ops->get_phase)
+		clk->phase = clk->ops->get_phase(clk->hw);
+	else
+		clk->phase = 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)
@@ -2087,14 +2161,16 @@ void clk_unregister(struct clk *clk)
 {
 	unsigned long flags;
 
-       if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
-               return;
+	if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
+		return;
+
+	clk_debug_unregister(clk);
 
 	clk_prepare_lock();
 
 	if (clk->ops == &clk_nodrv_ops) {
 		pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
-		goto out;
+		return;
 	}
 	/*
 	 * Assign empty clock ops for consumers that might still hold
@@ -2113,16 +2189,13 @@ void clk_unregister(struct clk *clk)
 			clk_set_parent(child, NULL);
 	}
 
-	clk_debug_unregister(clk);
-
 	hlist_del_init(&clk->child_node);
 
 	if (clk->prepare_count)
 		pr_warn("%s: unregistering prepared clock: %s\n",
 					__func__, clk->name);
-
 	kref_put(&clk->ref, __clk_release);
-out:
+
 	clk_prepare_unlock();
 }
 EXPORT_SYMBOL_GPL(clk_unregister);