348 lines
11 KiB
C
348 lines
11 KiB
C
/****************************************************************************
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* arch/arm/src/stm32l4/stm32l4_oneshot_lowerhalf.c
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*
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* Copyright (C) 2016 Gregory Nutt. All rights reserved.
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* Authors: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <time.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/irq.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/timers/oneshot.h>
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#include "stm32l4_oneshot.h"
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/* This structure describes the state of the oneshot timer lower-half
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* driver
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*/
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struct stm32l4_oneshot_lowerhalf_s
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{
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/* This is the part of the lower half driver that is visible to the upper-
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* half client of the driver. This must be the first thing in this
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* structure so that pointers to struct oneshot_lowerhalf_s are cast
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* compatible to struct stm32l4_oneshot_lowerhalf_s and vice versa.
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*/
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struct oneshot_lowerhalf_s lh; /* Common lower-half driver fields */
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/* Private lower half data follows */
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struct stm32l4_oneshot_s oneshot; /* STM32-specific oneshot state */
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oneshot_callback_t callback; /* internal handler that receives callback */
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FAR void *arg; /* Argument that is passed to the handler */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static void stm32l4_oneshot_handler(void *arg);
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static int stm32l4_max_delay(FAR struct oneshot_lowerhalf_s *lower,
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FAR struct timespec *ts);
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static int stm32l4_start(FAR struct oneshot_lowerhalf_s *lower,
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oneshot_callback_t callback, FAR void *arg,
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FAR const struct timespec *ts);
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static int stm32l4_cancel(FAR struct oneshot_lowerhalf_s *lower,
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FAR struct timespec *ts);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* Lower half operations */
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static const struct oneshot_operations_s g_oneshot_ops =
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{
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.max_delay = stm32l4_max_delay,
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.start = stm32l4_start,
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.cancel = stm32l4_cancel,
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: stm32l4_oneshot_handler
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*
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* Description:
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* Timer expiration handler
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*
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* Input Parameters:
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* arg - Should be the same argument provided when stm32l4_oneshot_start()
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* was called.
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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static void stm32l4_oneshot_handler(void *arg)
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{
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FAR struct stm32l4_oneshot_lowerhalf_s *priv =
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(FAR struct stm32l4_oneshot_lowerhalf_s *)arg;
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oneshot_callback_t callback;
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FAR void *cbarg;
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DEBUGASSERT(priv != NULL);
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/* Perhaps the callback was nullified in a race condition with
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* stm32l4_cancel?
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*/
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if (priv->callback)
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{
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/* Sample and nullify BEFORE executing callback (in case the callback
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* restarts the oneshot).
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*/
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callback = priv->callback;
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cbarg = priv->arg;
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priv->callback = NULL;
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priv->arg = NULL;
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/* Then perform the callback */
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callback(&priv->lh, cbarg);
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}
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}
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/****************************************************************************
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* Name: stm32l4_max_delay
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*
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* Description:
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* Determine the maximum delay of the one-shot timer (in microseconds)
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*
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* Input Parameters:
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* lower An instance of the lower-half oneshot state structure. This
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* structure must have been previously initialized via a call to
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* oneshot_initialize();
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* ts The location in which to return the maximum delay.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned
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* on failure.
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*
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****************************************************************************/
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static int stm32l4_max_delay(FAR struct oneshot_lowerhalf_s *lower,
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FAR struct timespec *ts)
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{
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FAR struct stm32l4_oneshot_lowerhalf_s *priv =
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(FAR struct stm32l4_oneshot_lowerhalf_s *)lower;
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uint64_t usecs;
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int ret;
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DEBUGASSERT(priv != NULL && ts != NULL);
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ret = stm32l4_oneshot_max_delay(&priv->oneshot, &usecs);
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if (ret >= 0)
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{
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uint64_t sec = usecs / 1000000;
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usecs -= 1000000 * sec;
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ts->tv_sec = (time_t)sec;
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ts->tv_nsec = (long)(usecs * 1000);
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}
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return ret;
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}
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/****************************************************************************
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* Name: stm32l4_start
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*
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* Description:
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* Start the oneshot timer
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*
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* Input Parameters:
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* lower An instance of the lower-half oneshot state structure. This
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* structure must have been previously initialized via a call to
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* oneshot_initialize();
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* handler The function to call when when the oneshot timer expires.
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* arg An opaque argument that will accompany the callback.
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* ts Provides the duration of the one shot timer.
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*
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* Returned Value:
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* Zero (OK) is returned on success; a negated errno value is returned
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* on failure.
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*
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****************************************************************************/
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static int stm32l4_start(FAR struct oneshot_lowerhalf_s *lower,
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oneshot_callback_t callback, FAR void *arg,
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FAR const struct timespec *ts)
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{
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FAR struct stm32l4_oneshot_lowerhalf_s *priv =
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(FAR struct stm32l4_oneshot_lowerhalf_s *)lower;
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irqstate_t flags;
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int ret;
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DEBUGASSERT(priv != NULL && callback != NULL && ts != NULL);
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/* Save the callback information and start the timer */
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flags = enter_critical_section();
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priv->callback = callback;
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priv->arg = arg;
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ret = stm32l4_oneshot_start(&priv->oneshot,
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stm32l4_oneshot_handler, priv, ts);
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leave_critical_section(flags);
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if (ret < 0)
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{
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tmrerr("ERROR: stm32l4_oneshot_start failed: %d\n", flags);
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}
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return ret;
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}
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/****************************************************************************
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* Name: stm32l4_cancel
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*
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* Description:
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* Cancel the oneshot timer and return the time remaining on the timer.
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*
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* NOTE: This function may execute at a high rate with no timer running (as
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* when pre-emption is enabled and disabled).
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*
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* Input Parameters:
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* lower Caller allocated instance of the oneshot state structure. This
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* structure must have been previously initialized via a call to
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* oneshot_initialize();
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* ts The location in which to return the time remaining on the
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* oneshot timer. A time of zero is returned if the timer is
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* not running.
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*
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* Returned Value:
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* Zero (OK) is returned on success. A call to up_timer_cancel() when
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* the timer is not active should also return success; a negated errno
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* value is returned on any failure.
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*
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****************************************************************************/
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static int stm32l4_cancel(FAR struct oneshot_lowerhalf_s *lower,
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FAR struct timespec *ts)
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{
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FAR struct stm32l4_oneshot_lowerhalf_s *priv =
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(FAR struct stm32l4_oneshot_lowerhalf_s *)lower;
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irqstate_t flags;
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int ret;
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DEBUGASSERT(priv != NULL);
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/* Cancel the timer */
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flags = enter_critical_section();
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ret = stm32l4_oneshot_cancel(&priv->oneshot, ts);
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priv->callback = NULL;
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priv->arg = NULL;
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leave_critical_section(flags);
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if (ret < 0)
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{
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tmrerr("ERROR: stm32l4_oneshot_cancel failed: %d\n", flags);
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}
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: oneshot_initialize
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*
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* Description:
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* Initialize the oneshot timer and return a oneshot lower half driver
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* instance.
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*
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* Input Parameters:
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* chan Timer counter channel to be used.
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* resolution The required resolution of the timer in units of
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* microseconds. NOTE that the range is restricted to the
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* range of uint16_t (excluding zero).
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*
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* Returned Value:
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* On success, a non-NULL instance of the oneshot lower-half driver is
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* returned. NULL is return on any failure.
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*
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****************************************************************************/
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FAR struct oneshot_lowerhalf_s *oneshot_initialize(int chan,
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uint16_t resolution)
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{
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FAR struct stm32l4_oneshot_lowerhalf_s *priv;
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int ret;
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/* Allocate an instance of the lower half driver */
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priv = (FAR struct stm32l4_oneshot_lowerhalf_s *)
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kmm_zalloc(sizeof(struct stm32l4_oneshot_lowerhalf_s));
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if (priv == NULL)
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{
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tmrerr("ERROR: Failed to initialized state structure\n");
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return NULL;
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}
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/* Initialize the lower-half driver structure */
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priv->lh.ops = &g_oneshot_ops;
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/* Initialize the contained STM32 oneshot timer */
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ret = stm32l4_oneshot_initialize(&priv->oneshot, chan, resolution);
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if (ret < 0)
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{
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tmrerr("ERROR: stm32l4_oneshot_initialize failed: %d\n", ret);
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kmm_free(priv);
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return NULL;
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}
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return &priv->lh;
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}
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