[v4,1/5] rtc: sysfs: facilitate attribute add to rtc device

Message ID 20180710090710.9066-2-Denis.Osterland@diehl.com
State New
Headers show
Series
  • rtc: isl1208: fixes, documentation and isl1219 support
Related show

Commit Message

Denis OSTERLAND July 10, 2018, 9:44 a.m.
From: Denis Osterland <Denis.Osterland@diehl.com>

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

In case groups were not yet registered (kobj.state_in_sysfs == 0)
rtc_add_group just addes given group to dev.groups,
otherwise it uses devm_device_add_group.

Signed-off-by: Denis Osterland <Denis.Osterland@diehl.com>
---
 drivers/rtc/rtc-core.h  |  6 ++++++
 drivers/rtc/rtc-sysfs.c | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)

Patch

diff --git a/drivers/rtc/rtc-core.h b/drivers/rtc/rtc-core.h
index 0abf98983e13..81d1c3ce7a96 100644
--- a/drivers/rtc/rtc-core.h
+++ b/drivers/rtc/rtc-core.h
@@ -40,9 +40,15 @@  static inline void rtc_proc_del_device(struct rtc_device *rtc)
 
 #ifdef CONFIG_RTC_INTF_SYSFS
 const struct attribute_group **rtc_get_dev_attribute_groups(void);
+int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
 #else
 static inline const struct attribute_group **rtc_get_dev_attribute_groups(void)
 {
 	return NULL;
 }
+static inline
+int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
+{
+	return 0;
+}
 #endif
diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
index 454da38c6012..9a177b8f761b 100644
--- a/drivers/rtc/rtc-sysfs.c
+++ b/drivers/rtc/rtc-sysfs.c
@@ -317,3 +317,42 @@  const struct attribute_group **rtc_get_dev_attribute_groups(void)
 {
 	return rtc_attr_groups;
 }
+
+static size_t rtc_group_count(struct rtc_device *rtc)
+{
+	const struct attribute_group **groups = rtc->dev.groups;
+	size_t cnt = 0;
+
+	if (groups)
+		for (; *groups; groups++)
+			cnt++;
+
+	return cnt;
+}
+
+static inline int
+__rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
+{
+	size_t cnt = rtc_group_count(rtc);
+	const struct attribute_group **groups, **old;
+
+	groups = devm_kzalloc(&rtc->dev, (cnt+2)*sizeof(*groups), GFP_KERNEL);
+	if (IS_ERR_OR_NULL(groups))
+		return PTR_ERR(groups);
+	memcpy(groups, rtc->dev.groups, cnt*sizeof(*groups));
+	groups[cnt] = grp;
+
+	old = rtc->dev.groups;
+	rtc->dev.groups = groups;
+	if (old != rtc_attr_groups)
+		devm_kfree(&rtc->dev, old);
+
+	return 0;
+}
+
+int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
+{
+	return rtc->dev.kobj.state_in_sysfs ?
+		devm_device_add_group(&rtc->dev, grp) :
+		__rtc_add_group(rtc, grp);
+}