ARM: SAMSUNG: add clock_tree debugfs file in clock

Add a clock/clock_tree debugfs file that shows the entire clock
hierarchy including usage counts and rates.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
[kgene.kim@samsung.com: silence checkpatch complaining]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/plat-samsung/clock.c

@@ -389,6 +389,64 @@ int __init s3c24xx_register_baseclocks(unsigned long xtal)
 
 static struct dentry *clk_debugfs_root;
 
+static void clock_tree_show_one(struct seq_file *s, struct clk *c, int level)
+{
+	struct clk *child;
+	const char *state;
+	char buf[255] = { 0 };
+	int n = 0;
+
+	if (c->name)
+		n = snprintf(buf, sizeof(buf) - 1, "%s", c->name);
+
+	if (c->devname)
+		n += snprintf(buf + n, sizeof(buf) - 1 - n, ":%s", c->devname);
+
+	state = (c->usage > 0) ? "on" : "off";
+
+	seq_printf(s, "%*s%-*s %-6s %-3d %-10lu\n",
+		   level * 3 + 1, "",
+		   50 - level * 3, buf,
+		   state, c->usage, clk_get_rate(c));
+
+	list_for_each_entry(child, &clocks, list) {
+		if (child->parent != c)
+			continue;
+
+		clock_tree_show_one(s, child, level + 1);
+	}
+}
+
+static int clock_tree_show(struct seq_file *s, void *data)
+{
+	struct clk *c;
+	unsigned long flags;
+
+	seq_printf(s, " clock state ref rate\n");
+	seq_printf(s, "----------------------------------------------------\n");
+
+	spin_lock_irqsave(&clocks_lock, flags);
+
+	list_for_each_entry(c, &clocks, list)
+		if (c->parent == NULL)
+			clock_tree_show_one(s, c, 0);
+
+	spin_unlock_irqrestore(&clocks_lock, flags);
+	return 0;
+}
+
+static int clock_tree_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, clock_tree_show, inode->i_private);
+}
+
+static const struct file_operations clock_tree_fops = {
+	.open		= clock_tree_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 static int clk_debugfs_register_one(struct clk *c)
 {
 	int err;
@@ -446,13 +504,18 @@ static int __init clk_debugfs_init(void)
 {
 	struct clk *c;
 	struct dentry *d;
-	int err;
+	int err = -ENOMEM;
 
 	d = debugfs_create_dir("clock", NULL);
 	if (!d)
 		return -ENOMEM;
 	clk_debugfs_root = d;
 
+	d = debugfs_create_file("clock_tree", S_IRUGO, clk_debugfs_root, NULL,
+				 &clock_tree_fops);
+	if (!d)
+		goto err_out;
+
 	list_for_each_entry(c, &clocks, list) {
 		err = clk_debugfs_register(c);
 		if (err)