nuttx/arch/arm/src/stm32wb/stm32wb_pmstandby.c

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2022-06-30 10:57:20 +02:00
/****************************************************************************
* arch/arm/src/stm32wb/stm32wb_pmstandby.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdbool.h>
#include "nvic.h"
#include "stm32wb_pwr.h"
#include "stm32wb_pm.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: stm32wb_pmstandby
*
* Description:
* Enter STANDBY mode.
*
* Input Parameters:
* None
*
* Returned Value:
* On success, this function will not return (STANDBY mode can only be
* terminated with a reset event). Otherwise, STANDBY mode did not occur
* and a negated errno value is returned to indicate the cause of the
* failure.
*
****************************************************************************/
int stm32wb_pmstandby(void)
{
uint32_t regval;
/* Clear the Wake-Up Flags by setting the CWUFx bits in the power status
* clear register
*/
regval = PWR_SCR_CWUF1 | PWR_SCR_CWUF2 | PWR_SCR_CWUF3 |
PWR_SCR_CWUF4 | PWR_SCR_CWUF5;
putreg32(regval, STM32WB_PWR_SCR);
/* Select Standby mode */
regval = getreg32(STM32WB_PWR_CR1);
regval &= ~PWR_CR1_LPMS_MASK;
regval |= PWR_CR1_LPMS_STANDBY;
putreg32(regval, STM32WB_PWR_CR1);
/* Set SLEEPDEEP bit of Cortex System Control Register */
regval = getreg32(NVIC_SYSCON);
regval |= NVIC_SYSCON_SLEEPDEEP;
putreg32(regval, NVIC_SYSCON);
/* Sleep until the wakeup reset occurs */
__asm__ volatile ("wfi");
return OK; /* Won't get here */
}