nuttx/arch/arm/src/imxrt/imxrt_lpsrtc.c

/****************************************************************************
 * arch/arm/src/imxrt/imxrt_lpsrtc.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 <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <nuttx/timers/rtc.h>

#include <arch/board/board.h>

#include "arm_arch.h"

#include "hardware/imxrt_snvs.h"
#include "imxrt_periphclks.h"
#include "imxrt_hprtc.h"
#include "imxrt_lpsrtc.h"

#ifdef CONFIG_IMXRT_SNVS_LPSRTC

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: imxrt_lpsrtc_enable
 *
 * Description:
 *   Enable/start the LPRTC time counter.
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void imxrt_lpsrtc_enable(void)
{
  uint32_t regval;

  /* Enable the LPSRTC */

  regval  = getreg32(IMXRT_SNVS_LPCR);
  regval |= SVNS_LPCR_SRTCENV;
  putreg32(regval, IMXRT_SNVS_LPCR);

  while ((getreg32(IMXRT_SNVS_LPCR) & SVNS_LPCR_SRTCENV) == 0)
    {
    }
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: imxrt_lpsrtc_initialize
 *
 * Description:
 *   Initialize the LPSRTC per the selected configuration.
 *    This function is called via up_rtc_initialize (see imxrt_hprtc.c).
 *
 *   NOTE that the LPSRTC is always configured synchronized with the HPRTC.
 *    This means that the time is set via the LPSRTC but read via the HPRTC.
 *    Also, only the alarms from the HPRTC are used.
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno on failure
 *
 ****************************************************************************/

int imxrt_lpsrtc_initialize(void)
{
#ifdef CONFIG_IMXRTC_LPSRTC_CALENABLE
  uint32_t regval;
#endif

  /* Initialize the HPRTC */

  imxrt_hprtc_initialize();

  /* Enable clocking to the the SNVS LP module.
   * Clock is on during all modes, except STOP mode.
   */

  imxrt_clockall_snvs_lp();

#ifdef CONFIG_IMXRTC_LPSRTC_CALENABLE
  /* Set the LPSRTC calibration value */

  regval  = getreg32(IMXRT_SNVS_LPCR);
  regval &= ~SNVS_LPCR_LPCALBVAL_MASK;
  regval |= SNVS_LPCR_LPCALBVAL(CONFIG_IMXRTC_LPSRTC_CALVALUE);
  regval |= SNVS_LPCR_LPCALBEN;
  putreg32(regval, IMXRT_SNVS_LPCR);
#endif

  /* Disable tamper pins.
   * TODO:  I don't think this applies the currently supported device.
   */

  /* Enable the LPSRTC */

  imxrt_lpsrtc_enable();

  /* Synchronize HPRTC time with the LPSRTC and enable HPRTC */

  imxrt_hprtc_synchronize();
  return OK;
}

/****************************************************************************
 * Name: up_rtc_time
 *
 * Description:
 *   Get the current time in seconds.  This is similar to the standard time()
 *   function.  This interface is only required if the low-resolution
 *   RTC/counter hardware implementation selected.  It is only used by the
 *   RTOS during initialization to set up the system time when CONFIG_RTC is
 *   set but neither CONFIG_RTC_HIRES nor CONFIG_RTC_DATETIME are set.
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   The current time in seconds
 *
 ****************************************************************************/

#ifndef CONFIG_RTC_HIRES
time_t up_rtc_time(void)
{
  /* Delegate to imxrt_hprtc_time() */

  return imxrt_hprtc_time();
}
#endif

/****************************************************************************
 * Name: up_rtc_settime
 *
 * Description:
 *   Set the RTC to the provided time.  All RTC implementations must be able
 *   to set their time based on a standard timespec.
 *
 * Input Parameters:
 *   tp - the time to use
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno on failure
 *
 ****************************************************************************/

int up_rtc_settime(FAR const struct timespec *ts)
{
  uint32_t regval;

  DEBUGASSERT(ts != NULL);

  /* Disable the LPSRTC */

  regval  = getreg32(IMXRT_SNVS_LPCR);
  regval &= ~SNVS_LPCR_MCENV;
  putreg32(regval, IMXRT_SNVS_LPCR);

  while ((getreg32(IMXRT_SNVS_LPCR) & SNVS_LPCR_MCENV) != 0)
    {
    }

  /* Set LPSRTC time in seconds.  We could do better by accounting for the
   * ts->tv_nsec unused residual.
   *
   * IMXRT_SNVS_LPSMCMR Bits 9-14 = 15-bit MSB of alarm setting.
   * IMXRT_SNVS_LPSMCLR 32-bit LSB of alarm setting.
   */

  putreg32((uint32_t)ts->tv_sec >> 17, IMXRT_SNVS_LPSMCMR);
  putreg32((uint32_t)ts->tv_sec << 15, IMXRT_SNVS_LPSMCLR);

  /* The time has been set */

  putreg32(CONFIG_IMXRT_RTC_MAGIC,
           IMXRT_SNVS_LPGPR(CONFIG_IMXRT_RTC_MAGIC_REG));

  /* Unconditionally re-enable the LPSRTC */

  imxrt_lpsrtc_enable();
  return OK;
}

/****************************************************************************
 * Name: imxrt_lpsrtc_havesettime
 *
 * Description:
 *   Check if the LPSRTC time has been set
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   Returns true if RTC date-time have been previously set.
 *
 ****************************************************************************/

bool imxrt_lpsrtc_havesettime(void)
{
  return (getreg32(IMXRT_SNVS_LPGPR(CONFIG_IMXRT_RTC_MAGIC_REG)) ==
          CONFIG_IMXRT_RTC_MAGIC);
}
#endif /* CONFIG_IMXRT_SNVS_LPSRTC */