rtc: sysfs: facilitate attribute add to rtc device
This patches addresses following problem:
rtc_allocate_device
devm_device_add_group <-- kernel oops / null pointer, because
sysfs entry does not yet exist
rtc_register_device
rc = devm_device_add_group
if (rc)
return rc; <-- forbidden to return error code
after device register
This patch adds rtc_add_group(s) functions.
The functions store the sum of attribute groups as device resource.
Signed-off-by: Denis Osterland <Denis.Osterland@diehl.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
index 454da38..f1ff30a 100644
--- a/drivers/rtc/rtc-sysfs.c
+++ b/drivers/rtc/rtc-sysfs.c
@@ -317,3 +317,46 @@
{
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);