Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * drivers/base/interface.c - common driverfs interface that's exported to
3 * the world for all devices.
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 *
8 * This file is released under the GPLv2
9 *
10 */
11
12#include <linux/device.h>
13#include <linux/err.h>
14#include <linux/stat.h>
15#include <linux/string.h>
16
17/**
18 * detach_state - control the default power state for the device.
19 *
20 * This is the state the device enters when it's driver module is
21 * unloaded. The value is an unsigned integer, in the range of 0-4.
22 * '0' indicates 'On', so no action will be taken when the driver is
23 * unloaded. This is the default behavior.
24 * '4' indicates 'Off', meaning the driver core will call the driver's
25 * shutdown method to quiesce the device.
26 * 1-3 indicate a low-power state for the device to enter via the
27 * driver's suspend method.
28 */
29
30static ssize_t detach_show(struct device * dev, char * buf)
31{
32 return sprintf(buf, "%u\n", dev->detach_state);
33}
34
35static ssize_t detach_store(struct device * dev, const char * buf, size_t n)
36{
37 u32 state;
38 state = simple_strtoul(buf, NULL, 10);
39 if (state > 4)
40 return -EINVAL;
41 dev->detach_state = state;
42 return n;
43}
44
45static DEVICE_ATTR(detach_state, 0644, detach_show, detach_store);
46
47
48struct attribute * dev_default_attrs[] = {
49 &dev_attr_detach_state.attr,
50 NULL,
51};