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nuttx/arch/arm/src/nrf52/nrf52_tim_lowerhalf.c

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/****************************************************************************
* arch/arm/src/nrf52/nrf52_tim_lowerhalf.h
*
* 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 <sys/types.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/timers/timer.h>
#include "arm_arch.h"
#include "nrf52_tim.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* TIMER configuration */
#define NRF52_TIMER_CC (NRF52_TIM_CC0)
#define NRF52_TIMER_INT (NRF52_TIM_INT_COMPARE0)
#define NRF52_TIMER_RES (NRF52_TIM_WIDTH_32B)
#define NRF52_TIMER_MAX (0xffffffff)
#define NRF52_TIMER_PRE (NRF52_TIM_PRE_1000000)
#define NRF52_TIMER_PER (1000000)
/****************************************************************************
* Private Types
****************************************************************************/
struct nrf52_timer_lowerhalf_s
{
FAR const struct timer_ops_s *ops; /* Lower half operations */
FAR struct nrf52_tim_dev_s *tim; /* nrf52 timer driver */
tccb_t callback; /* Current user interrupt callback */
FAR void *arg; /* Argument passed to upper half callback */
bool started; /* True: Timer has been started */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int nrf52_timer_handler(int irq, void *context, void *arg);
/* "Lower half" driver methods **********************************************/
static int nrf52_timer_start(FAR struct timer_lowerhalf_s *lower);
static int nrf52_timer_stop(FAR struct timer_lowerhalf_s *lower);
static int nrf52_timer_getstatus(FAR struct timer_lowerhalf_s *lower,
FAR struct timer_status_s *status);
static int nrf52_timer_settimeout(FAR struct timer_lowerhalf_s *lower,
uint32_t timeout);
static void nrf52_timer_setcallback(FAR struct timer_lowerhalf_s *lower,
tccb_t callback, FAR void *arg);
/****************************************************************************
* Private Data
****************************************************************************/
/* "Lower half" driver methods */
static const struct timer_ops_s g_nrf52_timer_ops =
{
.start = nrf52_timer_start,
.stop = nrf52_timer_stop,
.getstatus = nrf52_timer_getstatus,
.settimeout = nrf52_timer_settimeout,
.setcallback = nrf52_timer_setcallback,
.ioctl = NULL,
};
#ifdef CONFIG_NRF52_TIMER0
/* TIMER0 lower-half */
static struct nrf52_timer_lowerhalf_s g_nrf52_timer0_lowerhalf =
{
.ops = &g_nrf52_timer_ops,
};
#endif
#ifdef CONFIG_NRF52_TIMER1
/* TIMER1 lower-half */
static struct nrf52_timer_lowerhalf_s g_nrf52_timer1_lowerhalf =
{
.ops = &g_nrf52_timer_ops,
};
#endif
#ifdef CONFIG_NRF52_TIMER2
/* TIMER2 lower-half */
static struct nrf52_timer_lowerhalf_s g_nrf52_timer2_lowerhalf =
{
.ops = &g_nrf52_timer_ops,
};
#endif
#ifdef CONFIG_NRF52_TIMER3
/* TIMER3 lower-half */
static struct nrf52_timer_lowerhalf_s g_nrf52_timer3_lowerhalf =
{
.ops = &g_nrf52_timer_ops,
};
#endif
#ifdef CONFIG_NRF52_TIMER4
/* TIMER4 lower-half */
static struct nrf52_timer_lowerhalf_s g_nrf52_timer4_lowerhalf =
{
.ops = &g_nrf52_timer_ops,
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nrf52_timer_handler
*
* Description:
* Timer interrupt handler
*
* Input Parameters:
*
* Returned Value:
*
****************************************************************************/
static int nrf52_timer_handler(int irq, void *context, void *arg)
{
FAR struct nrf52_timer_lowerhalf_s *priv =
(FAR struct nrf52_timer_lowerhalf_s *)arg;
uint32_t next_interval_us = 0;
NRF52_TIM_ACKINT(priv->tim, NRF52_TIMER_INT);
if (priv->callback(&next_interval_us, priv->arg))
{
if (next_interval_us > 0)
{
NRF52_TIM_SETCC(priv->tim, NRF52_TIMER_CC, next_interval_us);
}
}
else
{
nrf52_timer_stop((struct timer_lowerhalf_s *)priv);
}
return OK;
}
/****************************************************************************
* Name: nrf52_timer_start
*
* Description:
* Start the timer, resetting the time to the current timeout,
*
* Input Parameters:
* lower - A pointer the publicly visible representation of
* the "lower-half" driver state structure.
*
* Returned Value:
* Zero on success; a negated errno value on failure.
*
****************************************************************************/
static int nrf52_timer_start(FAR struct timer_lowerhalf_s *lower)
{
FAR struct nrf52_timer_lowerhalf_s *priv =
(FAR struct nrf52_timer_lowerhalf_s *)lower;
int ret = OK;
DEBUGASSERT(priv);
if (priv->started == true)
{
/* Return EBUSY to indicate that the timer was already running */
ret = -EBUSY;
goto errout;
}
/* Configure TIMER mode and resolution */
NRF52_TIM_CONFIGURE(priv->tim, NRF52_TIM_MODE_TIMER, NRF52_TIMER_RES);
/* Clear counter on COMPARE event */
NRF52_TIM_SHORTS(priv->tim, NRF52_TIM_SHORT_COMPARE_CLEAR,
NRF52_TIMER_INT, true);
/* Configure prescaler */
NRF52_TIM_SETPRE(priv->tim, NRF52_TIMER_PRE);
/* Configure callback */
if (priv->callback != NULL)
{
NRF52_TIM_SETISR(priv->tim, nrf52_timer_handler, priv);
NRF52_TIM_ENABLEINT(priv->tim, NRF52_TIMER_INT);
}
NRF52_TIM_CLEAR(priv->tim);
NRF52_TIM_START(priv->tim);
priv->started = true;
errout:
return ret;
}
/****************************************************************************
* Name: nrf52_timer_stop
*
* Description:
* Stop the timer
*
* Input Parameters:
* lower - A pointer the publicly visible representation of
* the "lower-half" driver state structure.
*
* Returned Value:
* Zero on success; a negated errno value on failure.
*
****************************************************************************/
static int nrf52_timer_stop(FAR struct timer_lowerhalf_s *lower)
{
FAR struct nrf52_timer_lowerhalf_s *priv =
(FAR struct nrf52_timer_lowerhalf_s *)lower;
int ret = OK;
DEBUGASSERT(priv);
if (priv->started == false)
{
/* Return ENODEV to indicate that the timer was not running */
ret = -ENODEV;
goto errout;
}
NRF52_TIM_DISABLEINT(priv->tim, NRF52_TIMER_INT);
NRF52_TIM_SETISR(priv->tim, NULL, NULL);
NRF52_TIM_STOP(priv->tim);
priv->started = false;
errout:
return ret;
}
/****************************************************************************
* Name: nrf52_timer_getstatus
*
* Description:
* get timer status
*
* Input Parameters:
* lower - A pointer the publicly visible representation of the "lower-
* half" driver state structure.
* status - The location to return the status information.
*
* Returned Value:
* Zero on success; a negated errno value on failure.
*
****************************************************************************/
static int nrf52_timer_getstatus(FAR struct timer_lowerhalf_s *lower,
FAR struct timer_status_s *status)
{
FAR struct nrf52_timer_lowerhalf_s *priv =
(FAR struct nrf52_timer_lowerhalf_s *)lower;
DEBUGASSERT(priv);
DEBUGASSERT(status);
/* Return the status bit */
status->flags = 0;
if (priv->started == true)
{
status->flags |= TCFLAGS_ACTIVE;
}
if (priv->callback)
{
status->flags |= TCFLAGS_HANDLER;
}
/* TODO: timeout and time left */
status->timeout = 0;
status->timeleft = 0;
return OK;
}
/****************************************************************************
* Name: nrf52_timer_settimeout
*
* Description:
* Set a new timeout value (and reset the timer)
*
* Input Parameters:
* lower - A pointer the publicly visible representation of
* the "lower-half" driver state structure.
* timeout - The new timeout value in microseconds.
*
* Returned Value:
* Zero on success; a negated errno value on failure.
*
****************************************************************************/
static int nrf52_timer_settimeout(FAR struct timer_lowerhalf_s *lower,
uint32_t timeout)
{
FAR struct nrf52_timer_lowerhalf_s *priv =
(FAR struct nrf52_timer_lowerhalf_s *)lower;
uint64_t cc = 0;
int ret = OK;
DEBUGASSERT(priv);
if (priv->started == true)
{
ret = -EPERM;
goto errout;
}
if (timeout > NRF52_TIMER_MAX)
{
ret = -EINVAL;
goto errout;
}
cc = (timeout / 1000000) * NRF52_TIMER_PER;
NRF52_TIM_SETCC(priv->tim, NRF52_TIMER_CC, cc);
errout:
return ret;
}
/****************************************************************************
* Name: nrf52_setcallback
*
* Description:
* Call this user provided timeout handler.
*
* Input Parameters:
* lower - A pointer the publicly visible representation of
* the "lower-half" driver state structure.
* callback - The new timer expiration function pointer. If this
* function pointer is NULL, then the reset-on-expiration
* behavior is restored,
* arg - Argument that will be provided in the callback
*
* Returned Value:
* The previous timer expiration function pointer or NULL is there was
* no previous function pointer.
*
****************************************************************************/
static void nrf52_timer_setcallback(FAR struct timer_lowerhalf_s *lower,
tccb_t callback, FAR void *arg)
{
FAR struct nrf52_timer_lowerhalf_s *priv =
(FAR struct nrf52_timer_lowerhalf_s *)lower;
irqstate_t flags;
DEBUGASSERT(priv);
flags = enter_critical_section();
/* Save the new callback */
priv->callback = callback;
priv->arg = arg;
if (callback != NULL && priv->started == true)
{
NRF52_TIM_SETISR(priv->tim, nrf52_timer_handler, priv);
NRF52_TIM_ENABLEINT(priv->tim, NRF52_TIMER_INT);
}
else
{
NRF52_TIM_DISABLEINT(priv->tim, NRF52_TIMER_INT);
NRF52_TIM_SETISR(priv->tim, NULL, NULL);
}
leave_critical_section(flags);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nrf52_timer_initialize
*
* Description:
* Bind the configuration timer to a timer lower half instance and
* register the timer drivers at 'devpath'
*
* Input Parameters:
* devpath - The full path to the timer device. This should be of the
* form /dev/timer0
* timer - the timer's number.
*
* Returned Value:
* Zero (OK) is returned on success; A negated errno value is returned
* to indicate the nature of any failure.
*
****************************************************************************/
int nrf52_timer_initialize(FAR const char *devpath, uint8_t timer)
{
struct nrf52_timer_lowerhalf_s *lower = NULL;
FAR void *drvr = NULL;
int ret = OK;
DEBUGASSERT(devpath);
switch (timer)
{
#ifdef CONFIG_NRF52_TIMER0
case 0:
{
lower = &g_nrf52_timer0_lowerhalf;
break;
}
#endif
#ifdef CONFIG_NRF52_TIMER1
case 1:
{
lower = &g_nrf52_timer1_lowerhalf;
break;
}
#endif
#ifdef CONFIG_NRF52_TIMER2
case 2:
{
lower = &g_nrf52_timer2_lowerhalf;
break;
}
#endif
#ifdef CONFIG_NRF52_TIMER3
case 3:
{
lower = &g_nrf52_timer3_lowerhalf;
break;
}
#endif
#ifdef CONFIG_NRF52_TIMER4
case 4:
{
lower = &g_nrf52_timer4_lowerhalf;
break;
}
#endif
default:
{
ret = -ENODEV;
goto errout;
}
}
/* Initialize the elements of lower half state structure */
lower->started = false;
lower->callback = NULL;
lower->tim = nrf52_tim_init(timer);
if (lower->tim == NULL)
{
ret = -EINVAL;
goto errout;
}
/* Register the timer driver as /dev/timerX. The returned value from
* timer_register is a handle that could be used with timer_unregister().
* REVISIT: The returned handle is discard here.
*/
drvr = timer_register(devpath, (FAR struct timer_lowerhalf_s *)lower);
if (drvr == NULL)
{
/* The actual cause of the failure may have been a failure to allocate
* perhaps a failure to register the timer driver (such as if the
* 'depath' were not unique). We know here but we return EEXIST to
* indicate the failure (implying the non-unique devpath).
*/
ret = -EEXIST;
goto errout;
}
errout:
return ret;
}
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