rtc: switch to using is_visible() to control sysfs attributes

Instead of creating wakealarm attribute manually, after the device has been
registered, let's rely on facilities provided by the attribute groups to
control which attributes are visible and which are not. This allows to
create all needed attributes at once, at the same time that we register RTC
class device.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

1 files changed, 30 insertions, 29 deletions

diff --git a/drivers/rtc/rtc-sysfs.c b/drivers/rtc/rtc-sysfs.c
index e3ce1dc92b65..7273855ed02e 100644
--- a/drivers/rtc/rtc-sysfs.c
+++ b/drivers/rtc/rtc-sysfs.c
@@ -122,17 +122,6 @@ hctosys_show(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR_RO(hctosys);
 
-static struct attribute *rtc_attrs[] = {
-	&dev_attr_name.attr,
-	&dev_attr_date.attr,
-	&dev_attr_time.attr,
-	&dev_attr_since_epoch.attr,
-	&dev_attr_max_user_freq.attr,
-	&dev_attr_hctosys.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(rtc);
-
 static ssize_t
 wakealarm_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -222,6 +211,16 @@ wakealarm_store(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RW(wakealarm);
 
+static struct attribute *rtc_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_date.attr,
+	&dev_attr_time.attr,
+	&dev_attr_since_epoch.attr,
+	&dev_attr_max_user_freq.attr,
+	&dev_attr_hctosys.attr,
+	&dev_attr_wakealarm.attr,
+	NULL,
+};
 
 /* The reason to trigger an alarm with no process watching it (via sysfs)
  * is its side effect:  waking from a system state like suspend-to-RAM or
@@ -236,29 +235,31 @@ static bool rtc_does_wakealarm(struct rtc_device *rtc)
 	return rtc->ops->set_alarm != NULL;
 }
 
-
-void rtc_sysfs_add_device(struct rtc_device *rtc)
+static umode_t rtc_attr_is_visible(struct kobject *kobj,
+				   struct attribute *attr, int n)
 {
-	int err;
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct rtc_device *rtc = to_rtc_device(dev);
+	umode_t mode = attr->mode;
 
-	/* not all RTCs support both alarms and wakeup */
-	if (!rtc_does_wakealarm(rtc))
-		return;
+	if (attr == &dev_attr_wakealarm.attr)
+		if (!rtc_does_wakealarm(rtc))
+			mode = 0;
 
-	err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
-	if (err)
-		dev_err(rtc->dev.parent,
-			"failed to create alarm attribute, %d\n", err);
+	return mode;
 }
 
-void rtc_sysfs_del_device(struct rtc_device *rtc)
-{
-	/* REVISIT did we add it successfully? */
-	if (rtc_does_wakealarm(rtc))
-		device_remove_file(&rtc->dev, &dev_attr_wakealarm);
-}
+static struct attribute_group rtc_attr_group = {
+	.is_visible	= rtc_attr_is_visible,
+	.attrs		= rtc_attrs,
+};
+
+static const struct attribute_group *rtc_attr_groups[] = {
+	&rtc_attr_group,
+	NULL
+};
 
-void __init rtc_sysfs_init(struct class *rtc_class)
+const struct attribute_group **rtc_get_dev_attribute_groups(void)
 {
-	rtc_class->dev_groups = rtc_groups;
+	return rtc_attr_groups;
 }