nuttx/drivers/power/pm_checkstate.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 */