incubator-nuttx/drivers/sensors/hc_sr04.c

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/****************************************************************************
* drivers/sensors/hc_sr04.c
*
* 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 <assert.h>
#include <debug.h>
#include <stdio.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <nuttx/kmalloc.h>
#include <nuttx/mutex.h>
#include <nuttx/signal.h>
#include <nuttx/random.h>
#include <nuttx/sensors/hc_sr04.h>
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
#ifdef CONFIG_HCSR04_DEBUG
# define hcsr04_dbg(x, ...) _info(x, ##__VA_ARGS__)
#else
# define hcsr04_dbg(x, ...) sninfo(x, ##__VA_ARGS__)
#endif
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int hcsr04_open(FAR struct file *filep);
static int hcsr04_close(FAR struct file *filep);
static ssize_t hcsr04_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t hcsr04_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int hcsr04_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
static int hcsr04_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
/****************************************************************************
* Private Types
****************************************************************************/
struct hcsr04_dev_s
{
FAR struct hcsr04_config_s *config;
mutex_t devlock;
sem_t conv_donesem;
int time_start_pulse;
int time_finish_pulse;
volatile bool rising;
struct pollfd *fds[CONFIG_HCSR04_NPOLLWAITERS];
};
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_hcsr04ops =
{
hcsr04_open, /* open */
hcsr04_close, /* close */
hcsr04_read, /* read */
hcsr04_write, /* write */
NULL, /* seek */
hcsr04_ioctl, /* ioctl */
NULL, /* mmap */
NULL, /* truncate */
hcsr04_poll /* poll */
};
/****************************************************************************
* Private Functions
****************************************************************************/
static int hcsr04_read_distance(FAR struct hcsr04_dev_s *priv)
{
int done;
nxsem_get_value(&priv->conv_donesem, &done);
if (done == 0)
{
return (priv->time_finish_pulse - priv->time_start_pulse);
}
else
{
return -EAGAIN;
}
}
static int hcsr04_start_measuring(FAR struct hcsr04_dev_s *priv)
{
/* Configure the interruption */
priv->rising = true;
priv->config->irq_setmode(priv->config, priv->rising);
priv->config->irq_enable(priv->config, true);
/* Send to 10uS trigger pulse */
priv->config->set_trigger(priv->config, true);
nxsig_usleep(10);
priv->config->set_trigger(priv->config, false);
return 0;
}
static int hcsr04_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct hcsr04_dev_s *priv = inode->i_private;
int ret;
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
nxmutex_unlock(&priv->devlock);
hcsr04_dbg("OPENED\n");
return OK;
}
static int hcsr04_close(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct hcsr04_dev_s *priv = inode->i_private;
int ret;
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
nxmutex_unlock(&priv->devlock);
hcsr04_dbg("CLOSED\n");
return OK;
}
static ssize_t hcsr04_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct inode *inode = filep->f_inode;
FAR struct hcsr04_dev_s *priv = inode->i_private;
int distance = 0;
ssize_t length = 0;
int ret;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return (ssize_t)ret;
}
/* Setup and send a pulse to start measuring */
hcsr04_start_measuring(priv);
/* Wait the conversion to finish */
/* Get exclusive access */
ret = nxsem_wait_uninterruptible(&priv->conv_donesem);
if (ret < 0)
{
return (ssize_t)ret;
}
distance = hcsr04_read_distance(priv);
if (distance < 0)
{
hcsr04_dbg("failed to read the distance\n");
}
else
{
/* This interface is mainly intended for easy debugging in nsh. */
length = snprintf(buffer, buflen, "%d\n", distance);
if (length > buflen)
{
length = buflen;
}
}
nxmutex_unlock(&priv->devlock);
return length;
}
static ssize_t hcsr04_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
ssize_t length = 0;
return length;
}
static int hcsr04_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct hcsr04_dev_s *priv = inode->i_private;
int ret = OK;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
switch (cmd)
{
case SNIOC_START_CONVERSION:
ret = hcsr04_start_measuring(priv);
break;
case SNIOC_READ_RAW_DATA:
break;
#ifdef CONFIG_HCSR04_DEBUG
case SNIOC_DUMP_REGS:
ret = hcsr04_dump_registers(priv);
break;
#endif
default:
ret = -ENOTTY;
break;
}
nxmutex_unlock(&priv->devlock);
return ret;
}
static bool hcsr04_sample(FAR struct hcsr04_dev_s *priv)
{
int done;
nxsem_get_value(&priv->conv_donesem, &done);
return (done == 0);
}
static int hcsr04_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
FAR struct inode *inode;
FAR struct hcsr04_dev_s *priv;
uint32_t flags;
int ret = OK;
int i;
DEBUGASSERT(fds);
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Get exclusive access */
ret = nxmutex_lock(&priv->devlock);
if (ret < 0)
{
return ret;
}
if (setup)
{
/* Ignore waits that do not include POLLIN */
if ((fds->events & POLLIN) == 0)
{
ret = -EDEADLK;
goto out;
}
/* This is a request to set up the poll. Find an available slot for
* the poll structure reference.
*/
for (i = 0; i < CONFIG_HCSR04_NPOLLWAITERS; i++)
{
/* Find an available slot */
if (!priv->fds[i])
{
/* Bind the poll structure and this slot */
priv->fds[i] = fds;
fds->priv = &priv->fds[i];
break;
}
}
if (i >= CONFIG_HCSR04_NPOLLWAITERS)
{
fds->priv = NULL;
ret = -EBUSY;
goto out;
}
flags = enter_critical_section();
if (hcsr04_sample(priv))
{
poll_notify(priv->fds, CONFIG_HCSR04_NPOLLWAITERS, POLLIN);
}
leave_critical_section(flags);
}
else if (fds->priv)
{
/* This is a request to tear down the poll. */
struct pollfd **slot = (struct pollfd **)fds->priv;
DEBUGASSERT(slot != NULL);
/* Remove all memory of the poll setup */
*slot = NULL;
fds->priv = NULL;
}
out:
nxmutex_unlock(&priv->devlock);
return ret;
}
static int hcsr04_int_handler(int irq, FAR void *context, FAR void *arg)
{
FAR struct hcsr04_dev_s *priv = (FAR struct hcsr04_dev_s *)arg;
DEBUGASSERT(priv != NULL);
/* Is this the start of the pulse used to encode the distance ? */
if (priv->rising)
{
/* Get the clock ticks from the free running timer */
priv->time_start_pulse = priv->config->get_clock(priv->config);
/* Now we need to wait for the falling edge interruption */
priv->rising = false;
priv->config->irq_setmode(priv->config, priv->rising);
priv->config->irq_enable(priv->config, true);
}
else
{
/* Get the clock ticks from the free running timer */
priv->time_finish_pulse = priv->config->get_clock(priv->config);
/* Disable interruptions */
priv->config->irq_enable(priv->config, false);
/* Conversion is done */
nxsem_post(&priv->conv_donesem);
}
hcsr04_dbg("HC-SR04 interrupt\n");
poll_notify(priv->fds, CONFIG_HCSR04_NPOLLWAITERS, POLLIN);
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
int hcsr04_register(FAR const char *devpath,
FAR struct hcsr04_config_s *config)
{
int ret = 0;
FAR struct hcsr04_dev_s *priv;
priv = kmm_zalloc(sizeof(struct hcsr04_dev_s));
if (!priv)
{
hcsr04_dbg("Memory cannot be allocated for HC-SR04 sensor");
return -ENOMEM;
}
priv->config = config;
nxmutex_init(&priv->devlock);
nxsem_init(&priv->conv_donesem, 0, 0);
ret = register_driver(devpath, &g_hcsr04ops, 0666, priv);
if (ret < 0)
{
nxmutex_destroy(&priv->devlock);
nxsem_destroy(&priv->conv_donesem);
kmm_free(priv);
hcsr04_dbg("Error occurred during the driver registering = %d\n", ret);
return ret;
}
if (priv->config->irq_clear)
{
priv->config->irq_clear(priv->config);
}
priv->config->irq_attach(priv->config, hcsr04_int_handler, priv);
priv->config->irq_enable(priv->config, false);
return OK;
}