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incubator-nuttx/drivers/input/djoystick.c

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/****************************************************************************
* drivers/djoystick.c
*
* Copyright (C) 2014, 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/* This file provides a driver for a standard discrete joystick device. A
* discrete joystick refers to a joystick that could be implemented entirely
* with GPIO input pins. So up, down, left, and right are all discrete
* values like buttons (as opposed to integer values like you might obtain
* from an analog joystick).
*
* The discrete joystick driver exports a standard character driver
* interface. By convention, the discrete joystick is registered as an input
* device at /dev/djoyN where N uniquely identifies the driver instance.
*/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdbool.h>
#include <string.h>
#include <poll.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/signal.h>
#include <nuttx/random.h>
#include <nuttx/fs/fs.h>
#include <nuttx/input/djoystick.h>
#include <nuttx/irq.h>
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure provides the state of one discrete joystick driver */
struct djoy_upperhalf_s
{
/* Saved binding to the lower half discrete joystick driver */
FAR const struct djoy_lowerhalf_s *du_lower;
djoy_buttonset_t du_enabled; /* Set of currently enabled button interrupts */
djoy_buttonset_t du_sample; /* Last sampled button states */
sem_t du_exclsem; /* Supports exclusive access to the device */
/* The following is a singly linked list of open references to the
* joystick device.
*/
FAR struct djoy_open_s *du_open;
};
/* This structure describes the state of one open joystick driver instance */
struct djoy_open_s
{
/* Supports a singly linked list */
FAR struct djoy_open_s *do_flink;
/* The following will be true if we are closing */
volatile bool do_closing;
/* Joystick event notification information */
pid_t do_pid;
struct djoy_notify_s do_notify;
struct sigwork_s do_work;
/* Poll event information */
struct djoy_pollevents_s do_pollevents;
/* The following is a list if poll structures of threads waiting for
* driver events.
*/
FAR struct pollfd *do_fds[CONFIG_DJOYSTICK_NPOLLWAITERS];
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Semaphore helpers */
static inline int djoy_takesem(sem_t *sem);
#define djoy_givesem(s) nxsem_post(s);
/* Sampling and Interrupt handling */
static void djoy_enable(FAR struct djoy_upperhalf_s *priv);
static void djoy_interrupt(FAR const struct djoy_lowerhalf_s *lower,
FAR void *arg);
/* Sampling */
static void djoy_sample(FAR struct djoy_upperhalf_s *priv);
/* Character driver methods */
static int djoy_open(FAR struct file *filep);
static int djoy_close(FAR struct file *filep);
static ssize_t djoy_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static int djoy_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
static int djoy_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations djoy_fops =
{
djoy_open, /* open */
djoy_close, /* close */
djoy_read, /* read */
0, /* write */
0, /* seek */
djoy_ioctl, /* ioctl */
djoy_poll /* poll */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: djoy_takesem
****************************************************************************/
static inline int djoy_takesem(sem_t *sem)
{
return nxsem_wait(sem);
}
/****************************************************************************
* Name: djoy_enable
****************************************************************************/
static void djoy_enable(FAR struct djoy_upperhalf_s *priv)
{
FAR const struct djoy_lowerhalf_s *lower;
FAR struct djoy_open_s *opriv;
djoy_buttonset_t press;
djoy_buttonset_t release;
irqstate_t flags;
int i;
DEBUGASSERT(priv);
lower = priv->du_lower;
DEBUGASSERT(lower);
/* This routine is called both task level and interrupt level, so
* interrupts must be disabled.
*/
flags = enter_critical_section();
/* Visit each opened reference to the device */
press = 0;
release = 0;
for (opriv = priv->du_open; opriv; opriv = opriv->do_flink)
{
/* Are there any poll waiters? */
for (i = 0; i < CONFIG_DJOYSTICK_NPOLLWAITERS; i++)
{
if (opriv->do_fds[i])
{
/* Yes.. OR in the poll event buttons */
press |= opriv->do_pollevents.dp_press;
release |= opriv->do_pollevents.dp_release;
break;
}
}
/* OR in the signal events */
press |= opriv->do_notify.dn_press;
release |= opriv->do_notify.dn_release;
}
/* Enable/disable button interrupts */
DEBUGASSERT(lower->dl_enable);
if (press != 0 || release != 0)
{
/* Enable interrupts with the new button set */
lower->dl_enable(lower, press, release,
(djoy_interrupt_t)djoy_interrupt, priv);
}
else
{
/* Disable further interrupts */
lower->dl_enable(lower, 0, 0, NULL, NULL);
}
leave_critical_section(flags);
}
/****************************************************************************
* Name: djoy_interrupt
****************************************************************************/
static void djoy_interrupt(FAR const struct djoy_lowerhalf_s *lower,
FAR void *arg)
{
FAR struct djoy_upperhalf_s *priv = (FAR struct djoy_upperhalf_s *)arg;
DEBUGASSERT(priv);
/* Process the next sample */
djoy_sample(priv);
}
/****************************************************************************
* Name: djoy_sample
****************************************************************************/
static void djoy_sample(FAR struct djoy_upperhalf_s *priv)
{
FAR const struct djoy_lowerhalf_s *lower;
FAR struct djoy_open_s *opriv;
djoy_buttonset_t sample;
djoy_buttonset_t change;
djoy_buttonset_t press;
djoy_buttonset_t release;
irqstate_t flags;
int i;
DEBUGASSERT(priv);
lower = priv->du_lower;
DEBUGASSERT(lower);
/* This routine is called both task level and interrupt level, so
* interrupts must be disabled.
*/
flags = enter_critical_section();
/* Sample the new button state */
DEBUGASSERT(lower->dl_sample);
sample = lower->dl_sample(lower);
add_ui_randomness(sample);
/* Determine which buttons have been newly pressed and which have been
* newly released.
*/
change = sample ^ priv->du_sample;
press = change & sample;
DEBUGASSERT(lower->dl_supported);
release = change & (lower->dl_supported(lower) & ~sample);
/* Visit each opened reference to the device */
for (opriv = priv->du_open; opriv; opriv = opriv->do_flink)
{
/* Have any poll events occurred? */
if ((press & opriv->do_pollevents.dp_press) != 0 ||
(release & opriv->do_pollevents.dp_release) != 0)
{
/* Yes.. Notify all waiters */
for (i = 0; i < CONFIG_DJOYSTICK_NPOLLWAITERS; i++)
{
FAR struct pollfd *fds = opriv->do_fds[i];
if (fds)
{
fds->revents |= (fds->events & POLLIN);
if (fds->revents != 0)
{
iinfo("Report events: %02x\n", fds->revents);
nxsem_post(fds->sem);
}
}
}
}
/* Have any signal events occurred? */
if ((press & opriv->do_notify.dn_press) != 0 ||
(release & opriv->do_notify.dn_release) != 0)
{
/* Yes.. Signal the waiter */
opriv->do_notify.dn_event.sigev_value.sival_int = sample;
nxsig_notification(opriv->do_pid, &opriv->do_notify.dn_event,
SI_QUEUE, &opriv->do_work);
}
}
/* Enable/disable interrupt handling */
djoy_enable(priv);
priv->du_sample = sample;
leave_critical_section(flags);
}
/****************************************************************************
* Name: djoy_open
****************************************************************************/
static int djoy_open(FAR struct file *filep)
{
FAR struct inode *inode;
FAR struct djoy_upperhalf_s *priv;
FAR struct djoy_open_s *opriv;
FAR const struct djoy_lowerhalf_s *lower;
djoy_buttonset_t supported;
int ret;
DEBUGASSERT(filep && filep->f_inode);
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = (FAR struct djoy_upperhalf_s *)inode->i_private;
/* Get exclusive access to the driver structure */
ret = djoy_takesem(&priv->du_exclsem);
if (ret < 0)
{
ierr("ERROR: djoy_takesem failed: %d\n", ret);
return ret;
}
/* Allocate a new open structure */
opriv = (FAR struct djoy_open_s *)kmm_zalloc(sizeof(struct djoy_open_s));
if (!opriv)
{
ierr("ERROR: Failed to allocate open structure\n");
ret = -ENOMEM;
goto errout_with_sem;
}
/* Initialize the open structure */
lower = priv->du_lower;
DEBUGASSERT(lower && lower->dl_supported);
supported = lower->dl_supported(lower);
opriv->do_pollevents.dp_press = supported;
opriv->do_pollevents.dp_release = supported;
/* Attach the open structure to the device */
opriv->do_flink = priv->du_open;
priv->du_open = opriv;
/* Attach the open structure to the file structure */
filep->f_priv = (FAR void *)opriv;
ret = OK;
errout_with_sem:
djoy_givesem(&priv->du_exclsem);
return ret;
}
/****************************************************************************
* Name: djoy_close
****************************************************************************/
static int djoy_close(FAR struct file *filep)
{
FAR struct inode *inode;
FAR struct djoy_upperhalf_s *priv;
FAR struct djoy_open_s *opriv;
FAR struct djoy_open_s *curr;
FAR struct djoy_open_s *prev;
irqstate_t flags;
bool closing;
int ret;
DEBUGASSERT(filep && filep->f_priv && filep->f_inode);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = (FAR struct djoy_upperhalf_s *)inode->i_private;
/* Handle an improbable race conditions with the following atomic test
* and set.
*
* This is actually a pretty feeble attempt to handle this. The
* improbable race condition occurs if two different threads try to
* close the joystick driver at the same time. The rule: don't do
* that! It is feeble because we do not really enforce stale pointer
* detection anyway.
*/
flags = enter_critical_section();
closing = opriv->do_closing;
opriv->do_closing = true;
leave_critical_section(flags);
if (closing)
{
/* Another thread is doing the close */
return OK;
}
/* Get exclusive access to the driver structure */
ret = djoy_takesem(&priv->du_exclsem);
if (ret < 0)
{
ierr("ERROR: djoy_takesem failed: %d\n", ret);
return ret;
}
/* Find the open structure in the list of open structures for the device */
for (prev = NULL, curr = priv->du_open;
curr && curr != opriv;
prev = curr, curr = curr->do_flink);
DEBUGASSERT(curr);
if (!curr)
{
ierr("ERROR: Failed to find open entry\n");
ret = -ENOENT;
goto errout_with_exclsem;
}
/* Remove the structure from the device */
if (prev)
{
prev->do_flink = opriv->do_flink;
}
else
{
priv->du_open = opriv->do_flink;
}
/* Cancel any pending notification */
nxsig_cancel_notification(&opriv->do_work);
/* And free the open structure */
kmm_free(opriv);
/* Enable/disable interrupt handling */
djoy_enable(priv);
ret = OK;
errout_with_exclsem:
djoy_givesem(&priv->du_exclsem);
return ret;
}
/****************************************************************************
* Name: djoy_read
****************************************************************************/
static ssize_t djoy_read(FAR struct file *filep, FAR char *buffer,
size_t len)
{
FAR struct inode *inode;
FAR struct djoy_upperhalf_s *priv;
FAR const struct djoy_lowerhalf_s *lower;
int ret;
DEBUGASSERT(filep && filep->f_inode);
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = (FAR struct djoy_upperhalf_s *)inode->i_private;
/* Make sure that the buffer is sufficiently large to hold at least one
* complete sample.
*/
if (len < sizeof(djoy_buttonset_t))
{
ierr("ERROR: buffer too small: %lu\n", (unsigned long)len);
return -EINVAL;
}
/* Get exclusive access to the driver structure */
ret = djoy_takesem(&priv->du_exclsem);
if (ret < 0)
{
ierr("ERROR: djoy_takesem failed: %d\n", ret);
return ret;
}
/* Read and return the current state of the joystick buttons */
lower = priv->du_lower;
DEBUGASSERT(lower && lower->dl_sample);
priv->du_sample = lower->dl_sample(lower);
*(FAR djoy_buttonset_t *)buffer = priv->du_sample;
ret = sizeof(djoy_buttonset_t);
djoy_givesem(&priv->du_exclsem);
return (ssize_t)ret;
}
/****************************************************************************
* Name: djoy_ioctl
****************************************************************************/
static int djoy_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode;
FAR struct djoy_upperhalf_s *priv;
FAR struct djoy_open_s *opriv;
FAR const struct djoy_lowerhalf_s *lower;
int ret;
DEBUGASSERT(filep && filep->f_priv && filep->f_inode);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = (FAR struct djoy_upperhalf_s *)inode->i_private;
/* Get exclusive access to the driver structure */
ret = djoy_takesem(&priv->du_exclsem);
if (ret < 0)
{
ierr("ERROR: djoy_takesem failed: %d\n", ret);
return ret;
}
/* Handle the ioctl command */
ret = -EINVAL;
switch (cmd)
{
/* Command: DJOYIOC_SUPPORTED
* Description: Report the set of button events supported by the hardware;
* Argument: A pointer to writeable integer value in which to return
* the set of supported buttons.
* Return: Zero (OK) on success. Minus one will be returned on
* failure with the errno value set appropriately.
*/
case DJOYIOC_SUPPORTED:
{
FAR int *supported = (FAR int *)((uintptr_t)arg);
if (supported)
{
lower = priv->du_lower;
DEBUGASSERT(lower && lower->dl_supported);
*supported = (int)lower->dl_supported(lower);
ret = OK;
}
}
break;
/* Command: DJOYIOC_POLLEVENTS
* Description: Specify the set of button events that can cause a poll()
* to awaken. The default is all button depressions and
* all button releases (all supported buttons);
* Argument: A read-only pointer to an instance of struct
* djoy_pollevents_s
* Return: Zero (OK) on success. Minus one will be returned on
* failure with the errno value set appropriately.
*/
case DJOYIOC_POLLEVENTS:
{
FAR struct djoy_pollevents_s *pollevents =
(FAR struct djoy_pollevents_s *)((uintptr_t)arg);
if (pollevents)
{
/* Save the poll events */
opriv->do_pollevents.dp_press = pollevents->dp_press;
opriv->do_pollevents.dp_release = pollevents->dp_release;
/* Enable/disable interrupt handling */
djoy_enable(priv);
ret = OK;
}
}
break;
/* Command: DJOYIOC_REGISTER
* Description: Register to receive a signal whenever there is a change
* in any of the joystick discrete inputs. This feature,
* of course, depends upon interrupt GPIO support from the
* platform.
* Argument: A read-only pointer to an instance of struct
* djoy_notify_s
* Return: Zero (OK) on success. Minus one will be returned on
* failure with the errno value set appropriately.
*/
case DJOYIOC_REGISTER:
{
FAR struct djoy_notify_s *notify =
(FAR struct djoy_notify_s *)((uintptr_t)arg);
if (notify)
{
/* Save the notification events */
opriv->do_notify.dn_press = notify->dn_press;
opriv->do_notify.dn_release = notify->dn_release;
opriv->do_notify.dn_event = notify->dn_event;
opriv->do_pid = getpid();
/* Enable/disable interrupt handling */
djoy_enable(priv);
ret = OK;
}
}
break;
default:
ierr("ERROR: Unrecognized command: %ld\n", cmd);
ret = -ENOTTY;
break;
}
djoy_givesem(&priv->du_exclsem);
return ret;
}
/****************************************************************************
* Name: djoy_poll
****************************************************************************/
static int djoy_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
FAR struct inode *inode;
FAR struct djoy_upperhalf_s *priv;
FAR struct djoy_open_s *opriv;
int ret;
int i;
DEBUGASSERT(filep && filep->f_priv && filep->f_inode);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = (FAR struct djoy_upperhalf_s *)inode->i_private;
/* Get exclusive access to the driver structure */
ret = djoy_takesem(&priv->du_exclsem);
if (ret < 0)
{
ierr("ERROR: djoy_takesem failed: %d\n", ret);
return ret;
}
/* Are we setting up the poll? Or tearing it down? */
if (setup)
{
/* This is a request to set up the poll. Find an available
* slot for the poll structure reference
*/
for (i = 0; i < CONFIG_DJOYSTICK_NPOLLWAITERS; i++)
{
/* Find an available slot */
if (!opriv->do_fds[i])
{
/* Bind the poll structure and this slot */
opriv->do_fds[i] = fds;
fds->priv = &opriv->do_fds[i];
break;
}
}
if (i >= CONFIG_DJOYSTICK_NPOLLWAITERS)
{
ierr("ERROR: Too man poll waiters\n");
fds->priv = NULL;
ret = -EBUSY;
goto errout_with_dusem;
}
}
else if (fds->priv)
{
/* This is a request to tear down the poll. */
FAR struct pollfd **slot = (FAR struct pollfd **)fds->priv;
#ifdef CONFIG_DEBUG_FEATURES
if (!slot)
{
ierr("ERROR: Poll slot not found\n");
ret = -EIO;
goto errout_with_dusem;
}
#endif
/* Remove all memory of the poll setup */
*slot = NULL;
fds->priv = NULL;
}
errout_with_dusem:
djoy_givesem(&priv->du_exclsem);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: djoy_register
*
* Description:
* Bind the lower half discrete joystick driver to an instance of the
* upper half discrete joystick driver and register the composite character
* driver as the specific device.
*
* Input Parameters:
* devname - The name of the discrete joystick device to be registers.
* This should be a string of the form "/priv/djoyN" where N is the
* minor device number.
* lower - An instance of the platform-specific discrete joystick lower
* half driver.
*
* Returned Value:
* Zero (OK) is returned on success. Otherwise a negated errno value is
* returned to indicate the nature of the failure.
*
****************************************************************************/
int djoy_register(FAR const char *devname,
FAR const struct djoy_lowerhalf_s *lower)
{
FAR struct djoy_upperhalf_s *priv;
int ret;
DEBUGASSERT(devname && lower);
/* Allocate a new djoystick driver instance */
priv = (FAR struct djoy_upperhalf_s *)
kmm_zalloc(sizeof(struct djoy_upperhalf_s));
if (!priv)
{
ierr("ERROR: Failed to allocate device structure\n");
return -ENOMEM;
}
/* Make sure that all djoystick interrupts are disabled */
DEBUGASSERT(lower->dl_enable);
lower->dl_enable(lower, 0, 0, NULL, NULL);
/* Initialize the new djoystick driver instance */
priv->du_lower = lower;
nxsem_init(&priv->du_exclsem, 0, 1);
DEBUGASSERT(lower->dl_sample);
priv->du_sample = lower->dl_sample(lower);
/* And register the djoystick driver */
ret = register_driver(devname, &djoy_fops, 0666, priv);
if (ret < 0)
{
ierr("ERROR: register_driver failed: %d\n", ret);
nxsem_destroy(&priv->du_exclsem);
kmm_free(priv);
}
return ret;
}
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