rtc: class: make rtc_class constant

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the rtc_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Greg Kroah-Hartman <[email protected]>
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>

1 files changed, 13 insertions, 8 deletions

diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 921ee1827974..e31fa0ad127e 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -21,7 +21,6 @@
 #include "rtc-core.h"
 
 static DEFINE_IDA(rtc_ida);
-struct class *rtc_class;
 
 static void rtc_device_release(struct device *dev)
 {
@@ -199,6 +198,11 @@ static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
 #define RTC_CLASS_DEV_PM_OPS	NULL
 #endif
 
+const struct class rtc_class = {
+	.name = "rtc",
+	.pm = RTC_CLASS_DEV_PM_OPS,
+};
+
 /* Ensure the caller will set the id before releasing the device */
 static struct rtc_device *rtc_allocate_device(void)
 {
@@ -220,7 +224,7 @@ static struct rtc_device *rtc_allocate_device(void)
 
 	rtc->irq_freq = 1;
 	rtc->max_user_freq = 64;
-	rtc->dev.class = rtc_class;
+	rtc->dev.class = &rtc_class;
 	rtc->dev.groups = rtc_get_dev_attribute_groups();
 	rtc->dev.release = rtc_device_release;
 
@@ -475,13 +479,14 @@ EXPORT_SYMBOL_GPL(devm_rtc_device_register);
 
 static int __init rtc_init(void)
 {
-	rtc_class = class_create("rtc");
-	if (IS_ERR(rtc_class)) {
-		pr_err("couldn't create class\n");
-		return PTR_ERR(rtc_class);
-	}
-	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
+	int err;
+
+	err = class_register(&rtc_class);
+	if (err)
+		return err;
+
 	rtc_dev_init();
+
 	return 0;
 }
 subsys_initcall(rtc_init);