[PATCH v2 1/2] driver core: class: expose the class kobject

From: Bartosz Golaszewski
Date: Tue Oct 15 2024 - 04:00:47 EST


From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

Export the address of the /sys/class kobject to users that need to
chain off of it by means other than calling register_class(). This will
be used by the GPIO subsystem to provide a backward compatibility
mount-point for the GPIO sysfs class once it's disabled.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
drivers/base/class.c | 6 ++++++
include/linux/device/class.h | 6 ++++++
2 files changed, 12 insertions(+)

diff --git a/drivers/base/class.c b/drivers/base/class.c
index cb5359235c70..68474aff53df 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -23,6 +23,9 @@
/* /sys/class */
static struct kset *class_kset;

+struct kobject *class_kobj;
+EXPORT_SYMBOL_GPL(class_kobj);
+
#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)

/**
@@ -668,5 +671,8 @@ int __init classes_init(void)
class_kset = kset_create_and_add("class", NULL, NULL);
if (!class_kset)
return -ENOMEM;
+
+ class_kobj = &class_kset->kobj;
+
return 0;
}
diff --git a/include/linux/device/class.h b/include/linux/device/class.h
index 518c9c83d64b..898f7948293d 100644
--- a/include/linux/device/class.h
+++ b/include/linux/device/class.h
@@ -69,6 +69,12 @@ struct class {
const struct dev_pm_ops *pm;
};

+/*
+ * Global /sys/class kobject for creating sub-groups by means other than
+ * class_register().
+ */
+extern struct kobject *class_kobj;
+
struct class_dev_iter {
struct klist_iter ki;
const struct device_type *type;

--
2.43.0