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>
This commit is contained in:
Denis Osterland 2018-07-24 11:31:22 +00:00 committed by Alexandre Belloni
parent 5a5ba10f44
commit a0a1a1ba30
2 changed files with 57 additions and 0 deletions

View file

@ -40,9 +40,23 @@ 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);
int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
#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;
}
static inline
int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
{
return 0;
}
#endif

View file

@ -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);