samples/kobject/kobject-example.c

1 // SPDX-License-Identifier: GPL-2.0
5  * Copyright (C) 2004-2007 Greg Kroah-Hartman <greg@kroah.com>
16  * /sys/kernel/kobject-example  In that directory, 3 files are created:
17  * "foo", "baz", and "bar".  If an integer is written to these files, it can be
21 static int foo;  variable
23 static int bar;  variable
26  * The "foo" file where a static variable is read from and written to.
31 	return sysfs_emit(buf, "%d\n", foo);  in foo_show()
39 	ret = kstrtoint(buf, 10, &foo);  in foo_store()
46 /* Sysfs attributes cannot be world-writable. */
48 	__ATTR(foo, 0664, foo_show, foo_store);
52  * looking at the attribute for the "baz" and "bar" files.
59 	if (strcmp(attr->attr.name, "baz") == 0)  in b_show()
62 		var = bar;  in b_show()
75 	if (strcmp(attr->attr.name, "baz") == 0)  in b_store()
78 		bar = var;  in b_store()
85 	__ATTR(bar, 0664, b_show, b_store);
126 		return -ENOMEM;  in example_init()
144 MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");