1 files changed, 51 insertions, 0 deletions
diff --git a/drivers/base/interface.c b/drivers/base/interface.c
new file mode 100644
index 000000000000..bd515843a0cb
--- /dev/null
+++ b/drivers/base/interface.c
@@ -0,0 +1,51 @@
+/*
+ * drivers/base/interface.c - common driverfs interface that's exported to
+ * 	the world for all devices.
+ *
+ * Copyright (c) 2002-3 Patrick Mochel
+ * Copyright (c) 2002-3 Open Source Development Labs
+ *
+ * This file is released under the GPLv2
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+
+/**
+ *	detach_state - control the default power state for the device.
+ *
+ *	This is the state the device enters when it's driver module is
+ *	unloaded. The value is an unsigned integer, in the range of 0-4.
+ *	'0' indicates 'On', so no action will be taken when the driver is
+ *	unloaded. This is the default behavior.
+ *	'4' indicates 'Off', meaning the driver core will call the driver's
+ *	shutdown method to quiesce the device.
+ *	1-3 indicate a low-power state for the device to enter via the
+ *	driver's suspend method.
+ */
+
+static ssize_t detach_show(struct device * dev, char * buf)
+{
+	return sprintf(buf, "%u\n", dev->detach_state);
+}
+
+static ssize_t detach_store(struct device * dev, const char * buf, size_t n)
+{
+	u32 state;
+	state = simple_strtoul(buf, NULL, 10);
+	if (state > 4)
+		return -EINVAL;
+	dev->detach_state = state;
+	return n;
+}
+
+static DEVICE_ATTR(detach_state, 0644, detach_show, detach_store);
+
+
+struct attribute * dev_default_attrs[] = {
+	&dev_attr_detach_state.attr,
+	NULL,
+};