incubator-nuttx/drivers/power/pm_checkstate.c

97 lines
3.9 KiB
C

/****************************************************************************
* drivers/power/pm_checkstate.c
*
* Copyright (C) 2011-2012, 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
* Author: Matias Nitsche <mnitsche@dc.uba.ar>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <nuttx/power/pm.h>
#include <nuttx/clock.h>
#include <nuttx/irq.h>
#include "pm.h"
#ifdef CONFIG_PM
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pm_checkstate
*
* Description:
* This function is called from the MCU-specific IDLE loop to monitor the
* the power management conditions. This function returns the "recommended"
* power management state based on the PM policy applied by the currently
* chosen governor. The IDLE loop must call pm_changestate() in order to
* make the state change, which will interact with all drivers registered
* with the PM system.
*
* These two steps are separated because the plaform-specific IDLE loop may
* have additional situational information that is not available to the
* the PM sub-system. For example, the IDLE loop may know that the
* battery charge level is very low and may force lower power states
* even if there is activity.
*
* NOTE: That these two steps are separated in time and, hence, the IDLE
* loop could be suspended for a long period of time between calling
* pm_checkstate() and pm_changestate(). The IDLE loop may need to make
* these calls atomic by either disabling interrupts until the state change
* is completed.
*
* Input Parameters:
* domain - the PM domain to check
*
* Returned Value:
* The recommended power management state.
*
****************************************************************************/
enum pm_state_e pm_checkstate(int domain)
{
DEBUGASSERT(domain >= 0 && domain < CONFIG_PM_NDOMAINS &&
g_pmglobals.governor->checkstate);
return g_pmglobals.governor->checkstate(domain);
}
#endif /* CONFIG_PM */