driver core: Add class_attr_string for simple read-only string
Several drivers just export a static string as class attributes.
Use the new extensible attribute support to define a simple
CLASS_ATTR_STRING() macro for this.
This will allow to remove code from drivers in followon patches.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 34a2de9..2e297cc 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -490,6 +490,16 @@
class_put(parent);
}
+ssize_t show_class_attr_string(struct class *class, struct class_attribute *attr,
+ char *buf)
+{
+ struct class_attribute_string *cs;
+ cs = container_of(attr, struct class_attribute_string, attr);
+ return snprintf(buf, PAGE_SIZE, "%s\n", cs->str);
+}
+
+EXPORT_SYMBOL_GPL(show_class_attr_string);
+
struct class_compat {
struct kobject *kobj;
};
diff --git a/include/linux/device.h b/include/linux/device.h
index 190f8d3..f95d5bfe 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -265,6 +265,23 @@
extern void class_remove_file(struct class *class,
const struct class_attribute *attr);
+/* Simple class attribute that is just a static string */
+
+struct class_attribute_string {
+ struct class_attribute attr;
+ char *str;
+};
+
+/* Currently read-only only */
+#define _CLASS_ATTR_STRING(_name, _mode, _str) \
+ { __ATTR(_name, _mode, show_class_attr_string, NULL), _str }
+#define CLASS_ATTR_STRING(_name, _mode, _str) \
+ struct class_attribute_string class_attr_##_name = \
+ _CLASS_ATTR_STRING(_name, _mode, _str)
+
+extern ssize_t show_class_attr_string(struct class *class, struct class_attribute *attr,
+ char *buf);
+
struct class_interface {
struct list_head node;
struct class *class;
