static void pwm_dump(FAR const char *msg, FAR const struct pwm_info_s *info,
bool started)
{
#ifdef CONFIG_PWM_MULTICHAN
int i;
#endif
pwminfo("%s: frequency: %d", msg, info->frequency);
#ifdef CONFIG_PWM_MULTICHAN
for (i = 0; i < CONFIG_PWM_NCHANNELS; i++)
{
pwminfo(" channel: %d duty: %08x",
info->channels[i].channel, info->channels[i].duty);
}
#else
pwminfo(" duty: %08x", info->duty);
#endif
#ifdef CONFIG_PWM_PULSECOUNT
pwminfo(" count: %d\n", info->count);
#endif
pwminfo(" started: %d\n", started);
}
static int pwm_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct pwm_upperhalf_s *upper = inode->i_private;
uint8_t tmp;
int ret;
pwminfo("crefs: %d\n", upper->crefs);
/* Get exclusive access to the device structures */
ret = nxsem_wait(&upper->exclsem);
if (ret < 0)
{
goto errout;
}
/* Increment the count of references to the device. If this the first
* time that the driver has been opened for this device, then initialize
* the device.
*/
tmp = upper->crefs + 1;
if (tmp == 0)
{
/* More than 255 opens; uint8_t overflows to zero */
ret = -EMFILE;
goto errout_with_sem;
}
/* Check if this is the first time that the driver has been opened. */
if (tmp == 1)
{
FAR struct pwm_lowerhalf_s *lower = upper->dev;
/* Yes.. perform one time hardware initialization. */
DEBUGASSERT(lower->ops->setup != NULL);
pwminfo("calling setup\n");
ret = lower->ops->setup(lower);
if (ret < 0)
{
goto errout_with_sem;
}
}
/* Save the new open count on success */
upper->crefs = tmp;
ret = OK;
errout_with_sem:
nxsem_post(&upper->exclsem);
errout:
return ret;
}
static int pwm_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct pwm_upperhalf_s *upper = inode->i_private;
int ret;
pwminfo("crefs: %d\n", upper->crefs);
/* Get exclusive access to the device structures */
ret = sem_wait(&upper->exclsem);
if (ret < 0)
{
ret = -get_errno();
goto errout;
}
/* Decrement the references to the driver. If the reference count will
* decrement to 0, then uninitialize the driver.
*/
if (upper->crefs > 1)
{
upper->crefs--;
}
else
{
FAR struct pwm_lowerhalf_s *lower = upper->dev;
/* There are no more references to the port */
upper->crefs = 0;
/* Disable the PWM device */
DEBUGASSERT(lower->ops->shutdown != NULL);
pwminfo("calling shutdown: %d\n");
lower->ops->shutdown(lower);
}
ret = OK;
//errout_with_sem:
sem_post(&upper->exclsem);
errout:
return ret;
}
void pwm_expired(FAR void *handle)
{
FAR struct pwm_upperhalf_s *upper = (FAR struct pwm_upperhalf_s *)handle;
pwminfo("started: %d waiting: %d\n", upper->started, upper->waiting);
/* Make sure that the PWM is started */
if (upper->started)
{
/* Is there a thread waiting for the pulse train to complete? */
if (upper->waiting)
{
/* Yes.. clear the waiting flag and awakened the waiting thread */
upper->waiting = false;
sem_post(&upper->waitsem);
}
/* The PWM is now stopped */
upper->started = false;
}
}
int pwm_register(FAR const char *path, FAR struct pwm_lowerhalf_s *dev)
{
FAR struct pwm_upperhalf_s *upper;
/* Allocate the upper-half data structure */
upper = (FAR struct pwm_upperhalf_s *)kmm_zalloc(sizeof(struct pwm_upperhalf_s));
if (!upper)
{
pwmerr("Allocation failed\n");
return -ENOMEM;
}
/* Initialize the PWM device structure (it was already zeroed by kmm_zalloc()) */
sem_init(&upper->exclsem, 0, 1);
#ifdef CONFIG_PWM_PULSECOUNT
sem_init(&upper->waitsem, 0, 0);
#endif
upper->dev = dev;
/* Register the PWM device */
pwminfo("Registering %s\n", path);
return register_driver(path, &g_pwmops, 0666, upper);
}
int pwm_register(FAR const char *path, FAR struct pwm_lowerhalf_s *dev)
{
FAR struct pwm_upperhalf_s *upper;
/* Allocate the upper-half data structure */
upper = (FAR struct pwm_upperhalf_s *)kmm_zalloc(sizeof(struct pwm_upperhalf_s));
if (!upper)
{
pwmerr("Allocation failed\n");
return -ENOMEM;
}
/* Initialize the PWM device structure (it was already zeroed by kmm_zalloc()) */
sem_init(&upper->exclsem, 0, 1);
#ifdef CONFIG_PWM_PULSECOUNT
sem_init(&upper->waitsem, 0, 0);
/* The wait semaphore is used for signaling and, hence, should not have priority
* inheritance enabled.
*/
sem_setprotocol(&upper->waitsem, SEM_PRIO_NONE);
#endif
upper->dev = dev;
/* Register the PWM device */
pwminfo("Registering %s\n", path);
return register_driver(path, &g_pwmops, 0666, upper);
}
static int pwm_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct pwm_upperhalf_s *upper = inode->i_private;
FAR struct pwm_lowerhalf_s *lower = upper->dev;
int ret;
pwminfo("cmd: %d arg: %ld\n", cmd, arg);
/* Get exclusive access to the device structures */
ret = sem_wait(&upper->exclsem);
if (ret < 0)
{
return ret;
}
/* Handle built-in ioctl commands */
switch (cmd)
{
/* PWMIOC_SETCHARACTERISTICS - Set the characteristics of the next pulsed
* output. This command will neither start nor stop the pulsed output.
* It will either setup the configuration that will be used when the
* output is started; or it will change the characteristics of the pulsed
* output on the fly if the timer is already started.
*
* ioctl argument: A read-only reference to struct pwm_info_s that provides
* the characteristics of the pulsed output.
*/
case PWMIOC_SETCHARACTERISTICS:
{
FAR const struct pwm_info_s *info = (FAR const struct pwm_info_s *)((uintptr_t)arg);
DEBUGASSERT(info != NULL && lower->ops->start != NULL);
pwm_dump("PWMIOC_SETCHARACTERISTICS", info, upper->started);
/* Save the pulse train characteristics */
memcpy(&upper->info, info, sizeof(struct pwm_info_s));
/* If PWM is already running, then re-start it with the new characteristics */
if (upper->started)
{
#ifdef CONFIG_PWM_PULSECOUNT
ret = lower->ops->start(lower, &upper->info, upper);
#else
ret = lower->ops->start(lower, &upper->info);
#endif
}
}
break;
/* PWMIOC_GETCHARACTERISTICS - Get the currently selected characteristics of
* the pulsed output (independent of whether the output is start or stopped).
*
* ioctl argument: A reference to struct pwm_info_s to receive the
* characteristics of the pulsed output.
*/
case PWMIOC_GETCHARACTERISTICS:
{
FAR struct pwm_info_s *info = (FAR struct pwm_info_s *)((uintptr_t)arg);
DEBUGASSERT(info != NULL);
memcpy(info, &upper->info, sizeof(struct pwm_info_s));
pwm_dump("PWMIOC_GETCHARACTERISTICS", info, upper->started);
}
break;
/* PWMIOC_START - Start the pulsed output. The PWMIOC_SETCHARACTERISTICS
* command must have previously been sent.
*
* ioctl argument: None
*/
case PWMIOC_START:
{
pwm_dump("PWMIOC_START", &upper->info, upper->started);
DEBUGASSERT(lower->ops->start != NULL);
/* Start the pulse train */
ret = pwm_start(upper, filep->f_oflags);
}
break;
/* PWMIOC_STOP - Stop the pulsed output.
*
* ioctl argument: None
*/
case PWMIOC_STOP:
{
pwminfo("PWMIOC_STOP: started: %d\n", upper->started);
DEBUGASSERT(lower->ops->stop != NULL);
if (upper->started)
{
ret = lower->ops->stop(lower);
upper->started = false;
#ifdef CONFIG_PWM_PULSECOUNT
if (upper->waiting)
{
upper->waiting = false;
}
#endif
}
}
break;
/* Any unrecognized IOCTL commands might be platform-specific ioctl commands */
default:
{
pwminfo("Forwarding unrecognized cmd: %d arg: %ld\n", cmd, arg);
DEBUGASSERT(lower->ops->ioctl != NULL);
ret = lower->ops->ioctl(lower, cmd, arg);
}
break;
}
sem_post(&upper->exclsem);
return ret;
}
static int pwm_start(FAR struct pwm_upperhalf_s *upper, unsigned int oflags)
{
FAR struct pwm_lowerhalf_s *lower = upper->dev;
irqstate_t flags;
int ret = OK;
DEBUGASSERT(upper != NULL && lower->ops->start != NULL);
/* Verify that the PWM is not already running */
if (!upper->started)
{
/* Disable interrupts to avoid race conditions */
flags = enter_critical_section();
/* Indicate that if will be waiting for the pulse count to complete.
* Note that we will only wait if a non-zero pulse count is specified
* and if the PWM driver was opened in normal, blocking mode. Also
* assume for now that the pulse train will be successfully started.
*
* We do these things before starting the PWM to avoid race conditions.
*/
upper->waiting = (upper->info.count > 0) && ((oflags & O_NONBLOCK) == 0);
upper->started = true;
/* Invoke the bottom half method to start the pulse train */
ret = lower->ops->start(lower, &upper->info, upper);
/* A return value of zero means that the pulse train was started
* successfully.
*/
if (ret == OK)
{
/* Should we wait for the pulse output to complete? Loop in
* in case the wakeup form sem_wait() is a false alarm.
*/
while (upper->waiting)
{
/* Wait until we are awakened by pwm_expired(). When
* pwm_expired is called, it will post the waitsem and
* clear the waiting flag.
*/
int tmp = sem_wait(&upper->waitsem);
DEBUGASSERT(tmp == OK || get_errno() == EINTR);
}
}
else
{
/* Looks like we won't be waiting after all */
pwminfo("start failed: %d\n", ret);
upper->started = false;
upper->waiting = false;
}
leave_critical_section(flags);
}
return ret;
}
