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