lupyuen/local-nuttx-update
1
0
Fork 0
forked from nuttx/nuttx-update
Code Pull requests Activity

drivers/sensors/hc_sr04.c: Replace busy wait with semaphone. Using this solution we don't need 60ms delay.

Browse source
This commit is contained in:
Alan Carvalho de Assis 2017-08-18 09:44:38 -06:00 committed by Gregory Nutt
parent 169c55e546
commit 1048a3b871
1 changed files with 15 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

26
drivers/sensors/hc_sr04.c
View file

@ -84,9 +84,9 @@ struct hcsr04_dev_s
{
FAR struct hcsr04_config_s *config;
sem_t devsem;
sem_t conv_donesem;
int time_start_pulse;
int time_finish_pulse;
volatile bool conv_done;
volatile bool rising;
#ifndef CONFIG_DISABLE_POLL
struct pollfd *fds[CONFIG_HCSR04_NPOLLWAITERS];
@ -119,7 +119,11 @@ static const struct file_operations g_hcsr04ops =
static int hcsr04_read_distance(FAR struct hcsr04_dev_s *priv)
{
if (priv->conv_done)
int done;
sem_getvalue(&priv->conv_donesem, &done);
if (done == 0)
{
return (priv->time_finish_pulse - priv->time_start_pulse);
}
@ -131,13 +135,8 @@ static int hcsr04_read_distance(FAR struct hcsr04_dev_s *priv)
static int hcsr04_start_measuring(FAR struct hcsr04_dev_s *priv)
{
/* Delay 60ms between readings */
usleep(60000);
/* Configure the interruption */
priv->conv_done = false;
priv->rising = true;
priv->config->irq_setmode(priv->config, priv->rising);
priv->config->irq_enable(priv->config, true);
@ -201,9 +200,9 @@ static ssize_t hcsr04_read(FAR struct file *filep, FAR char *buffer,
/* Wait the convertion to finish */
while (!priv->conv_done)
while (sem_wait(&priv->conv_donesem) != 0)
{
/* busy wait */
assert(errno == EINTR);
}
distance = hcsr04_read_distance(priv);
@ -272,7 +271,11 @@ static int hcsr04_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
#ifndef CONFIG_DISABLE_POLL
static bool hcsr04_sample(FAR struct hcsr04_dev_s *priv)
{
return priv->conv_done;
int done;
sem_getvalue(&priv->conv_donesem, &done);
return (done == 0);
}
static void hcsr04_notify(FAR struct hcsr04_dev_s *priv)
@ -413,7 +416,7 @@ static int hcsr04_int_handler(int irq, FAR void *context, FAR void *arg)
/* Convertion is done */
priv->conv_done = true;
sem_post(&priv->conv_donesem);
}
hcsr04_dbg("HC-SR04 interrupt\n");
@ -444,6 +447,7 @@ int hcsr04_register(FAR const char *devpath,
priv->config = config;
sem_init(&priv->devsem, 0, 1);
sem_init(&priv->conv_donesem, 0, 0);
ret = register_driver(devpath, &g_hcsr04ops, 0666, priv);
if (ret < 0)