SAMA5 RTC: Beginning of an RTC driver for the SAMA5

3 files changed, 780 insertions, 0 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index f2981386c..c21281fe2 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -5810,3 +5810,9 @@
 	  preflight failures, and to use the file sector buffer as a bounce buffer
 	  when a user-supplied buffer is not suitable for DMA. From Mike Smith
 	  (2013-10-18).
+	* arch/arm/src/sama5/chip/sam_rtc.h and sam_wdt.h:  Add WDT and RTC
+	  register definition header files (2013-10-18).
+	* arch/arm/src/sama5/chip/sam_rtc.c and sam_rtc.h:  Basic RTC driver.
+	  Support for RTC alarms is fragmentary and this has not yet been hooked
+	  into the build system  (2013-10-18).
+
diff --git a/nuttx/arch/arm/src/sama5/sam_rtc.c b/nuttx/arch/arm/src/sama5/sam_rtc.c
new file mode 100644
index 000000000..e47d4c544
--- /dev/null
+++ b/nuttx/arch/arm/src/sama5/sam_rtc.c
@@ -0,0 +1,703 @@
+/************************************************************************************
+ * arch/arm/src/sama5/sam_rtc.c
+ *
+ *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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 <nuttx/arch.h>
+#include <nuttx/irq.h>
+#include <nuttx/rtc.h>
+
+#include <time.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <arch/board/board.h>
+
+#include "up_arch.h"
+
+#include "sam_rtc.h"
+
+#ifdef CONFIG_RTC
+
+/************************************************************************************
+ * Pre-processor Definitions
+ ************************************************************************************/
+/* Configuration ********************************************************************/
+/* This RTC implementation supports only date/time RTC hardware */
+
+#ifndef CONFIG_RTC_DATETIME
+#  error "CONFIG_RTC_DATETIME must be set to use this driver"
+#endif
+
+#ifdef CONFIG_RTC_HIRES
+#  error "CONFIG_RTC_HIRES must NOT be set with this driver"
+#endif
+
+#ifndef CONFIG_STM32_PWR
+#  error "CONFIG_STM32_PWR must selected to use this driver"
+#endif
+
+#define RTC_MAGIC 0xdeadbeef
+
+#ifndef CONFIG_DEBUG
+#  undef CONFIG_DEBUG_RTC
+#endif
+
+/* Constants ************************************************************************/
+
+/* Debug ****************************************************************************/
+
+#ifdef CONFIG_DEBUG_RTC
+#  define rtcdbg    dbg
+#  define rtcvdbg   vdbg
+#  define rtclldbg  lldbg
+#  define rtcllvdbg llvdbg
+#else
+#  define rtcdbg(x...)
+#  define rtcvdbg(x...)
+#  define rtclldbg(x...)
+#  define rtcllvdbg(x...)
+#endif
+
+/************************************************************************************
+ * Private Types
+ ************************************************************************************/
+
+/************************************************************************************
+ * Private Data
+ ************************************************************************************/
+
+/* Callback to use when the alarm expires */
+
+#ifdef CONFIG_RTC_ALARM
+static alarmcb_t g_alarmcb;
+#endif
+
+/************************************************************************************
+ * Public Data
+ ************************************************************************************/
+
+/* g_rtc_enabled is set true after the RTC has successfully initialized */
+
+volatile bool g_rtc_enabled = false;
+
+/************************************************************************************
+ * Private Functions
+ ************************************************************************************/
+/************************************************************************************
+ * Name: rtc_dumpregs
+ *
+ * Description:
+ *    Disable RTC write protection
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ************************************************************************************/
+
+#ifdef CONFIG_DEBUG_RTC
+static void rtc_dumpregs(FAR const char *msg)
+{
+  rtclldbg("%s:\n", msg);
+  rtclldbg("      CR: %08x\n", getreg32(SAM_RTC_CR));
+  rtclldbg("      MR: %08x\n", getreg32(SAM_RTC_MR));
+  rtclldbg("    TIMR: %08x\n", getreg32(SAM_RTC_TIMR));
+  rtclldbg("    CALR: %08x\n", getreg32(SAM_RTC_CALR));
+  rtclldbg("  TIMALR: %08x\n", getreg32(SAM_RTC_TIMALR));
+  rtclldbg("  CALALR: %08x\n", getreg32(SAM_RTC_CALALR));
+  rtclldbg("      SR: %08x\n", getreg32(SAM_RTC_SR));
+  rtclldbg("     IMR: %08x\n", getreg32(SAM_RTC_IMR));
+  rtclldbg("     VAR: %08x\n", getreg32(SAM_RTC_VER));
+}
+#else
+#  define rtc_dumpregs(msg)
+#endif
+
+/************************************************************************************
+ * Name: rtc_dumptime
+ *
+ * Description:
+ *    Disable RTC write protection
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   None
+ *
+ ************************************************************************************/
+
+#ifdef CONFIG_DEBUG_RTC
+static void rtc_dumptime(FAR struct tm *tp, FAR const char *msg)
+{
+  rtclldbg("%s:\n", msg);
+  rtclldbg("  tm_sec: %08x\n", tp->tm_sec);
+  rtclldbg("  tm_min: %08x\n", tp->tm_min);
+  rtclldbg(" tm_hour: %08x\n", tp->tm_hour);
+  rtclldbg(" tm_mday: %08x\n", tp->tm_mday);
+  rtclldbg("  tm_mon: %08x\n", tp->tm_mon);
+  rtclldbg(" tm_year: %08x\n", tp->tm_year);
+}
+#else
+#  define rtc_dumptime(tp, msg)
+#endif
+
+/************************************************************************************
+ * Name: rtc_bin2bcd
+ *
+ * Description:
+ *   Converts a 2 digit binary to BCD format
+ *
+ * Input Parameters:
+ *   value - The byte to be converted.
+ *
+ * Returned Value:
+ *   The value in BCD representation
+ *
+ ************************************************************************************/
+
+static uint32_t rtc_bin2bcd(int value)
+{
+  uint32_t msbcd = 0;
+
+  while (value >= 10)
+    {
+      msbcd++;
+      value -= 10;
+    }
+
+  return (msbcd << 4) | value;
+}
+
+/************************************************************************************
+ * Name: rtc_bin2bcd
+ *
+ * Description:
+ *   Convert from 2 digit BCD to binary.
+ *
+ * Input Parameters:
+ *   value - The BCD value to be converted.
+ *
+ * Returned Value:
+ *   The value in binary representation
+ *
+ ************************************************************************************/
+
+static int rtc_bcd2bin(uint32_t value)
+{
+  uint32_t tens = (value >> 4) * 10;
+  return (int)(tens + (value & 0x0f));
+}
+
+/************************************************************************************
+ * Name: rtc_setup
+ *
+ * Description:
+ *   Performs first time configuration of the RTC.  A special value written into
+ *   back-up register 0 will prevent this function from being called on sub-sequent
+ *   resets or power up.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ************************************************************************************/
+
+static int rtc_setup(void)
+{
+#warning Missing logic
+
+  /* Set the 24 hour format */
+
+  putreg32(0, SAM_RTC_MR);
+  return OK;
+}
+
+/************************************************************************************
+ * Name: rtc_resume
+ *
+ * Description:
+ *   Called when the RTC was already initialized on a previous power cycle.  This
+ *   just brings the RTC back into full operation.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ************************************************************************************/
+
+static int rtc_resume(void)
+{
+  int ret;
+
+#warning Missing logic
+
+#ifdef CONFIG_RTC_ALARM
+  /* Clear the RTC alarm flags */
+#warning Missing logic
+#endif
+
+  return ret;
+}
+
+/************************************************************************************
+ * Name: rtc_interrupt
+ *
+ * Description:
+ *    RTC interrupt service routine
+ *
+ * Input Parameters:
+ *   irq - The IRQ number that generated the interrupt
+ *   context - Architecture specific register save information.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; A negated errno value on failure.
+ *
+ ************************************************************************************/
+
+#if CONFIG_RTC_ALARM
+static int rtc_interrupt(int irq, void *context)
+{
+#warning "Missing logic"
+  return OK;
+}
+#endif
+
+/************************************************************************************
+ * Public Functions
+ ************************************************************************************/
+
+/************************************************************************************
+ * Name: up_rtcinitialize
+ *
+ * Description:
+ *   Initialize the hardware RTC per the selected configuration.  This function is
+ *   called once during the OS initialization sequence
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ************************************************************************************/
+
+int up_rtcinitialize(void)
+{
+  uint32_t regval;
+  int ret;
+
+  rtc_dumpregs("On reset");
+
+  /* No clocking setup need be performed. */
+
+  /* Check if the one-time initialization of the RTC has already been performed.
+   * We can determine this by checking if the magic number has been written to
+   * to back-up date register SYS_GPBR0.
+   */
+
+  if (getreg32(SAM_SYS_GPBR0) != RTC_MAGIC)
+    {
+      /* Perform the one-time setup of the LSE clocking to the RTC */
+
+      ret = rtc_setup();
+
+      /* Remember that the RTC is initialized */
+
+      putreg32(RTC_MAGIC, SAM_SYS_GPBR0));
+    }
+  else
+    {
+      /* RTC already set-up, just resume normal operation */
+
+      ret = rtc_resume();
+    }
+
+#ifdef CONFIG_RTC_ALARM
+  /* Then attach the ALARM interrupt handler */
+
+  irq_attach(SAM_PID_SYS, rtc_interrupt);
+
+  /* Should RTC alarm interrupt be enabled at the peripheral?  Let's assume so
+   * for now.
+   */
+#warning REVISIT
+  putreg32(RTC_IER_ALREN, SAM_RTC_IDR);
+
+  /* Enable SYSC interrupts at the AIC */
+
+  up_enable_irq(SAM_PID_SYS);
+#endif
+
+  g_rtc_enabled = true;
+  rtc_dumpregs("After Initialization");
+  return OK;
+}
+
+/************************************************************************************
+ * Name: up_rtc_getdatetime
+ *
+ * Description:
+ *   Get the current date and time from the date/time RTC.  This interface
+ *   is only supported by the date/time RTC hardware implementation.
+ *   It is used to replace the system timer.  It is only used by the RTOS during
+ *   intialization to set up the system time when CONFIG_RTC and CONFIG_RTC_DATETIME
+ *   are selected (and CONFIG_RTC_HIRES is not).
+ *
+ *   NOTE: Some date/time RTC hardware is capability of sub-second accuracy.  That
+ *   sub-second accuracy is lost in this interface.  However, since the system time
+ *   is reinitialized on each power-up/reset, there will be no timing inaccuracy in
+ *   the long run.
+ *
+ * Input Parameters:
+ *   tp - The location to return the high resolution time value.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ************************************************************************************/
+
+int up_rtc_getdatetime(FAR struct tm *tp)
+{
+  uint32_t timr;
+  uint32_t calr;
+  uint32_t cent;
+  uint32_t year;
+  uint32_t tmp;
+
+  /* Sample the data time registers.  There is a race condition here... If we sample
+   * the time just before midnight on December 31, the date could be wrong because
+   * the day rolled over while were sampling.
+   */
+
+  do
+    {
+      calr  = getreg32(SAM_RTC_CALR);
+      timr  = getreg32(SAM_RTC_TIMR);
+      tmp   = getreg32(SAM_RTC_CALR);
+    }
+  while (tmp != dr);
+
+  rtc_dumpregs("Reading Time");
+
+  /* Convert the RTC time register fields to struct tm format.
+   *
+   *   struct tm       TIMR register
+   *   tm_sec    0-61* SEC    (0-59)
+   *   tm_min    0-59  MIN    (0-59)
+   *   tm_hour   0-23  HOUR   (0-23)
+   *
+   *  *To allow for leap seconds.  But these never actuall happen.
+   */
+
+  tmp = (timr & RTC_TIMR_SEC_MASK) >> RTC_TIMR_SEC_SHIFT;
+  tp->tm_sec = rtc_bcd2bin(tmp);
+
+  tmp = (timr & RTC_TIMR_MIN_MASK) >> RTC_TIMR_MIN_SHIFT;
+  tp->tm_min = rtc_bcd2bin(tmp);
+
+  tmp = (timr & RTC_TIMR_HOUR_MASK) >> RTC_TIMR_HOUR_SHIFT;
+  tp->tm_hour = rtc_bcd2bin(tmp);
+
+  /* Convert the RTC date register fields to struct tm format.
+   *
+   *   struct tm       TIMR register
+   *   tm_mday   1-31  DATE   (1-31)
+   *   tm_wday   0-6   DAY    (1-7)  **
+   *   tm_mon    0-11  MONTH: (1-12)
+   *   tm_year   *     YEAR   (0-99)
+   *                   CENT   (19-20)
+   *
+   *  *Years since 1900
+   * **Day of the week is not supported
+   */
+
+  tmp  = (calr & RTC_CALR_DATE_SHIFT) >> RTC_CALR_DATE_MASK;
+  tp->tm_mday = rtc_bcd2bin(tmp);
+
+  tmp  = (calr & RTC_CALR_MONTH_SHIFT) >> RTC_CALR_MONTH_MASK;
+  tp->tm_mon = rtc_bcd2bin(tmp) - 1;
+
+  tmp  = (calr & RTC_CALR_CENT_SHIFT) >> RTC_CALR_CENT_MASK;
+  cent =  rtc_bcd2bin(tmp)
+  tmp  = (calr & RTC_CALR_YEAR_SHIFT) >> RTC_CALR_YEAR_MASK;
+  year =  rtc_bcd2bin(tmp)
+  tp->tm_year = cent * 100 + year - 1900;
+
+  rtc_dumptime(tp, "Returning");
+  return OK;
+}
+
+/************************************************************************************
+ * 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 *tp)
+{
+  FAR struct tm newtime;
+  uint32_t regval;
+  uint32_t timr;
+  uint32_t calr;
+  uint32_t cent;
+  uint32_t year;
+  int ret;
+
+  /* Break out the time values (note that the time is set only to units of seconds) */
+
+  (void)gmtime_r(&tp->tv_sec, &newtime);
+  rtc_dumptime(&newtime, "Setting time");
+
+  /* Then write the broken out values to the RTC */
+
+  /* Convert the struct tm format to RTC time register fields.
+   *
+   *   struct tm       TIMR register
+   *   tm_sec    0-61* SEC    (0-59)
+   *   tm_min    0-59  MIN    (0-59)
+   *   tm_hour   0-23  HOUR   (0-23)
+   *
+   *  *To allow for leap seconds.  But these never actuall happen.
+   */
+
+  timr  = (rtc_bin2bcd(newtime.tm_sec)  << RTC_TIMR_SEC_SHIFT)  & RTC_TIMR_SEC_MASK;
+  timr |= (rtc_bin2bcd(newtime.tm_min)  << RTC_TIMR_MIN_SHIFT)  & RTC_TIMR_MIN_MASK;
+  timr |= (rtc_bin2bcd(newtime.tm_hour) << RTC_TIMR_HOUR_SHIFT) & RTC_TIMR_HOUR_MASK;
+
+  /* Convert the struct tm format to RTC date register fields.
+   *
+   *   struct tm       CALR register
+   *   tm_mday   1-31  DATE   (1-31)
+   *   tm_wday   0-6   DAY    (1-7)  **
+   *   tm_mon    0-11  MONTH: (1-12)
+   *   tm_year   *     YEAR   (0-99)
+   *                   CENT   (19-20)
+   *
+   *  *Years since 1900
+   * **Day of the week is not supported
+   */
+
+  calr  = (rtc_bin2bcd(newtime.tm_mday)  << RTC_CALR_DATE_SHIFT) & RTC_CALR_DATE_MASK;
+  calr |= (rtc_bin2bcd(1)                << RTC_CALR_DAY_SHIFT)  & RTC_CALR_DAY_MASK;
+  calr |= (rtc_bin2bcd(newtime.tm_mon+1) << RTC_CALR_DATE_SHIFT) & RTC_CALR_DATE_MASK;
+
+  cent  = newtime.tm_year / 100 + 19;
+  year  = newtime.tm_year % 100;
+
+  calr |= (rtc_bin2bcd(year)             << RTC_CALR_YEAR_SHIFT) & RTC_CALR_YEAR_MASK;
+  calr |= (rtc_bin2bcd(cent)             << RTC_CALR_CENT_SHIFT) & RTC_CALR_CENT_MASK;
+
+  /* Stop RTC time counting */
+
+  regval  = getreg32(SAM_RTC_CR);
+  regval |= RTC_CR_UPDTIM;
+  putreg32(regval, SAM_RTC_CR);
+
+  /* Wait until the RTC has stopped so that we can update the time */
+
+  while ((getreg32(SAM_RTC_SR) & RTC_SR_ACKUPD) != RTC_SR_ACKUPD);
+
+  /* Clear the ACKUPD bit in the status register */
+
+  putreg32(RTC_SCCR_ACKCLR, SAM_RTC_SCCR);
+
+  /* Stop RTC date counting */
+
+  regval  = getreg32(SAM_RTC_CR);
+  regval |= RTC_CR_UPDCAL;
+  putreg32(regval, SAM_RTC_CR);
+
+  /* Wait until the counting has stopped so that we can update the time */
+
+  while ((getreg32(SAM_RTC_SR) & RTC_SR_ACKUPD) != RTC_SR_ACKUPD);
+
+  /* Clear the ACKUPD bit in the status register */
+
+  putreg32(RTC_SCCR_ACKCLR, SAM_RTC_SCCR);
+
+  /* Set the new date */
+
+  putreg32(calr, SAM_RTC_CALR);
+
+  /* Write the new time */
+
+  putreg32(timr, SAM_RTC_TIMR);
+
+  /* Resume RTC date/time counting */
+
+  regval  = getreg32(SAM_RTC_CR);
+  regval &= ~(RTC_CR_UPDTIM | RTC_CR_UPDCAL);
+  putreg32(regval, SAM_RTC_CR);
+
+  /* Clear the SEC status in the SR */
+
+  regval = getreg32(SAM_RTC_SCCR);
+  regval = RTC_SCCR_SECCLR;
+  putreg32(regval, SAM_RTC_SCCR);
+
+  DEBUGASSERT((getreg32(SAM_RTC_VER) & RTC_VER_NVTIM) == 0);
+  DEBUGASSERT((getreg32(SAM_RTC_VER) & RTC_VER_NVCAL) == 0);
+
+  rtc_dumpregs("New time setting");
+  return ret;
+}
+
+/************************************************************************************
+ * Name: up_rtc_setalarm
+ *
+ * Description:
+ *   Set up an alarm.  Up to two alarms can be supported (ALARM A and ALARM B).
+ *
+ * Input Parameters:
+ *   tp - the time to set the alarm
+ *   callback - the function to call when the alarm expires.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ************************************************************************************/
+
+#ifdef CONFIG_RTC_ALARM
+int up_rtc_setalarm(FAR const struct timespec *tp, alarmcb_t callback)
+{
+  FAR struct tm newalarm;
+  irqstate_t flags;
+  uint32_t regval;
+  uint32_t timalr;
+  uint32_t calalr;
+  uint32_t cent;
+  uint32_t year;
+  int ret = -EBUSY;
+
+  /* Is there already something waiting on the ALARM? */
+
+  flags = irqsave();
+  if (g_alarmcb == NULL)
+    {
+      /* No.. Save the callback function pointer */
+
+      g_alarmcb = callback;
+
+      /* Clear any pending alarm interrupts */
+
+      putreg32(RTC_SCCR_ALRCLR, SAM_RTC_SCCR);
+
+      /* Break out the time values (note that the time is set only to units
+       * of seconds)
+       */
+
+      (void)gmtime_r(&tp->tv_sec, &newalarm);
+      rtc_dumptime(&newalarm, "Setting alarm");
+
+      /* Then write the broken out values to the RTC */
+
+      /* Convert the struct tm format to RTC time register fields.
+       *
+       *   struct tm       TIMALR register
+       *   tm_sec    0-61* SEC    (0-59)
+       *   tm_min    0-59  MIN    (0-59)
+       *   tm_hour   0-23  HOUR   (0-23)
+       *
+       *  *To allow for leap seconds.  But these never actuall happen.
+       */
+
+      timalr  = (rtc_bin2bcd(newalarm.tm_sec)  << RTC_TIMRALR_SEC_SHIFT)  & RTC_TIMRALR_SEC_MASK;
+      timalr |= (rtc_bin2bcd(newalarm.tm_min)  << RTC_TIMRALR_MIN_SHIFT)  & RTC_TIMRALR_MIN_MASK;
+      timalr |= (rtc_bin2bcd(newalarm.tm_hour) << RTC_TIMRALR_HOUR_SHIFT) & RTC_TIMRALR_HOUR_MASK;
+      timalr |= (RTC_TIMALR_SECEN | RTC_TIMALR_MINEN | RTC_TIMALR_HOUREN);
+
+      /* Convert the struct tm format to RTC date register fields.
+       *
+       *   struct tm       CALALR register
+       *   tm_mday   1-31  DATE   (1-31)
+       *   tm_wday   0-6   DAY    (1-7)  **
+       *   tm_mon    0-11  MONTH: (1-12)
+       *   tm_year   *     YEAR   (0-99)
+       *                   CENT   (19-20)
+       *
+       *  *Years since 1900
+       * **Day of the week is not supported
+       */
+
+      calalr  = (rtc_bin2bcd(newalarm.tm_mday)  << RTC_CALALR_DATE_SHIFT) & RTC_CALALR_DATE_MASK;
+      calalr |= (rtc_bin2bcd(newalarm.tm_mon+1) << RTC_CALALR_DATE_SHIFT) & RTC_CALALR_DATE_MASK;
+      calalr |= (RTC_CALALR_MTHEN | RTC_CALALR_DATEEN)
+
+      /* Set the new date */
+
+      putreg32(calalr, SAM_RTC_CALALRR);
+
+      /* Write the new time */
+
+      putreg32(timalr, SAM_RTC_TIMALR);
+
+      DEBUGASSERT((getreg32(SAM_RTC_VER) & RTC_VER_NVTIMALR) == 0);
+      DEBUGASSERT((getreg32(SAM_RTC_VER) & RTC_VER_NVCALALR) == 0);
+
+      rtc_dumpregs("New alarm setting");
+
+      /* Enable alarm interrupts */
+
+      putreg32(RTC_IER_ALREN, SAM_RTC_IER);
+      ret = OK;
+    }
+
+  return ret;
+}
+#endif
+
+#endif /* CONFIG_RTC */
+
diff --git a/nuttx/arch/arm/src/sama5/sam_rtc.h b/nuttx/arch/arm/src/sama5/sam_rtc.h
new file mode 100644
index 000000000..2b3189054
--- /dev/null
+++ b/nuttx/arch/arm/src/sama5/sam_rtc.h
@@ -0,0 +1,71 @@
+/************************************************************************************
+ * arch/arm/src/sama5/stm_rtc.h
+ *
+ *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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
+ ************************************************************************************/
+
+#ifndef __ARCH_ARM_SRC_SAMA5_SAM_RTC_H
+#define __ARCH_ARM_SRC_SAMA5_SAM_RTC_H
+
+#include <nuttx/config.h>
+
+#include "chip.h"
+#include "chip/sam_rtc.h"
+
+/************************************************************************************
+ * Pre-processor Definitions
+ ************************************************************************************/
+
+#ifndef __ASSEMBLY__
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+/************************************************************************************
+ * Public Functions
+ ************************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_ARM_SRC_SAMA5_SAM_RTC_H */