1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
index 454da38c6012..f1ff30ade534 100644
--- a/drivers/rtc/rtc-sysfs.c
+++ b/drivers/rtc/rtc-sysfs.c
@@ -317,3 +317,46 @@ const struct attribute_group **rtc_get_dev_attribute_groups(void)
 {
 	return rtc_attr_groups;
 }
+
+int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
+{
+	size_t old_cnt = 0, add_cnt = 0, new_cnt;
+	const struct attribute_group **groups, **old;
+
+	if (rtc->registered)
+		return -EINVAL;
+	if (!grps)
+		return -EINVAL;
+
+	groups = rtc->dev.groups;
+	if (groups)
+		for (; *groups; groups++)
+			old_cnt++;
+
+	for (groups = grps; *groups; groups++)
+		add_cnt++;
+
+	new_cnt = old_cnt + add_cnt + 1;
+	groups = devm_kcalloc(&rtc->dev, new_cnt, sizeof(*groups), GFP_KERNEL);
+	if (IS_ERR_OR_NULL(groups))
+		return PTR_ERR(groups);
+	memcpy(groups, rtc->dev.groups, old_cnt * sizeof(*groups));
+	memcpy(groups + old_cnt, grps, add_cnt * sizeof(*groups));
+	groups[old_cnt + add_cnt] = NULL;
+
+	old = rtc->dev.groups;
+	rtc->dev.groups = groups;
+	if (old && old != rtc_attr_groups)
+		devm_kfree(&rtc->dev, old);
+
+	return 0;
+}
+EXPORT_SYMBOL(rtc_add_groups);
+
+int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
+{
+	const struct attribute_group *groups[] = { grp, NULL };
+
+	return rtc_add_groups(rtc, groups);
+}
+EXPORT_SYMBOL(rtc_add_group);