82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
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/*
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* drivers/base/power/runtime.c - Handling dynamic device power management.
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*
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* Copyright (c) 2003 Patrick Mochel
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* Copyright (c) 2003 Open Source Development Lab
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*
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*/
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#include <linux/device.h>
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#include "power.h"
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static void runtime_resume(struct device * dev)
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{
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dev_dbg(dev, "resuming\n");
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if (!dev->power.power_state)
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return;
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if (!resume_device(dev))
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dev->power.power_state = 0;
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}
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/**
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* dpm_runtime_resume - Power one device back on.
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* @dev: Device.
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*
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* Bring one device back to the on state by first powering it
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* on, then restoring state. We only operate on devices that aren't
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* already on.
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* FIXME: We need to handle devices that are in an unknown state.
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*/
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void dpm_runtime_resume(struct device * dev)
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{
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down(&dpm_sem);
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runtime_resume(dev);
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up(&dpm_sem);
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}
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/**
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* dpm_runtime_suspend - Put one device in low-power state.
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* @dev: Device.
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* @state: State to enter.
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*/
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int dpm_runtime_suspend(struct device * dev, pm_message_t state)
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{
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int error = 0;
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down(&dpm_sem);
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if (dev->power.power_state == state)
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goto Done;
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if (dev->power.power_state)
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runtime_resume(dev);
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if (!(error = suspend_device(dev, state)))
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dev->power.power_state = state;
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Done:
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up(&dpm_sem);
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return error;
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}
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/**
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* dpm_set_power_state - Update power_state field.
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* @dev: Device.
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* @state: Power state device is in.
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*
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* This is an update mechanism for drivers to notify the core
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* what power state a device is in. Device probing code may not
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* always be able to tell, but we need accurate information to
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* work reliably.
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*/
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void dpm_set_power_state(struct device * dev, pm_message_t state)
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{
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down(&dpm_sem);
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dev->power.power_state = state;
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up(&dpm_sem);
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}
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