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incubator-nuttx/drivers/input/button_upper.c

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/****************************************************************************
* drivers/input/button_upper.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.
*
****************************************************************************/
/* This file provides a driver for a button input devices.
*
* The buttons driver exports a standard character driver interface. By
* convention, the button driver is registered as an input device at
* /dev/btnN 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 <assert.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/buttons.h>
#include <nuttx/irq.h>
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure provides the state of one button driver */
struct btn_upperhalf_s
{
/* Saved binding to the lower half button driver */
FAR const struct btn_lowerhalf_s *bu_lower;
btn_buttonset_t bu_sample; /* Last sampled button states */
bool bu_enabled;
/* The following is a singly linked list of open references to the
* button device.
*/
FAR struct btn_open_s *bu_open;
#if CONFIG_INPUT_BUTTONS_DEBOUNCE_DELAY
struct wdog_s bu_wdog;
#endif
};
/* This structure describes the state of one open button driver instance */
struct btn_open_s
{
/* Supports a singly linked list */
FAR struct btn_open_s *bo_flink;
/* Button event notification information */
pid_t bo_pid;
struct btn_notify_s bo_notify;
struct sigwork_s bo_work;
/* Poll event information */
struct btn_pollevents_s bo_pollevents;
/* The following is a list if poll structures of threads waiting for
* driver events.
*/
bool bo_pending;
FAR struct pollfd *bo_fds[CONFIG_INPUT_BUTTONS_NPOLLWAITERS];
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Sampling and Interrupt handling */
static void btn_enable(FAR struct btn_upperhalf_s *priv);
static void btn_interrupt(FAR const struct btn_lowerhalf_s *lower,
FAR void *arg);
/* Sampling */
static void btn_sample(wdparm_t arg);
/* Character driver methods */
static int btn_open(FAR struct file *filep);
static int btn_close(FAR struct file *filep);
static ssize_t btn_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t btn_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int btn_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
static int btn_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_btn_fops =
{
btn_open, /* open */
btn_close, /* close */
btn_read, /* read */
btn_write, /* write */
NULL, /* seek */
btn_ioctl, /* ioctl */
NULL, /* mmap */
NULL, /* truncate */
btn_poll /* poll */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: btn_enable
****************************************************************************/
static void btn_enable(FAR struct btn_upperhalf_s *priv)
{
FAR const struct btn_lowerhalf_s *lower;
FAR struct btn_open_s *opriv;
btn_buttonset_t press;
btn_buttonset_t release;
irqstate_t flags;
DEBUGASSERT(priv && priv->bu_lower);
lower = priv->bu_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->bu_open; opriv; opriv = opriv->bo_flink)
{
/* OR in the poll event buttons */
press |= opriv->bo_pollevents.bp_press;
release |= opriv->bo_pollevents.bp_release;
/* OR in the signal events */
press |= opriv->bo_notify.bn_press;
release |= opriv->bo_notify.bn_release;
}
/* Enable/disable button interrupts */
DEBUGASSERT(lower->bl_enable);
if (press != 0 || release != 0)
{
/* Update last sampled button states when enabling interrupts for
* the first time.
*/
if (!priv->bu_enabled)
{
priv->bu_enabled = true;
priv->bu_sample = lower->bl_buttons(lower);
}
/* Enable interrupts with the new button set */
lower->bl_enable(lower, press, release,
(btn_handler_t)btn_interrupt, priv);
}
else
{
priv->bu_enabled = false;
/* Disable further interrupts */
lower->bl_enable(lower, 0, 0, NULL, NULL);
}
leave_critical_section(flags);
}
/****************************************************************************
* Name: btn_interrupt
****************************************************************************/
static void btn_interrupt(FAR const struct btn_lowerhalf_s *lower,
FAR void *arg)
{
FAR struct btn_upperhalf_s *priv = (FAR struct btn_upperhalf_s *)arg;
DEBUGASSERT(priv);
/* Process the next sample */
#if CONFIG_INPUT_BUTTONS_DEBOUNCE_DELAY
wd_start(&priv->bu_wdog, MSEC2TICK(CONFIG_INPUT_BUTTONS_DEBOUNCE_DELAY),
btn_sample, (wdparm_t)priv);
#else
btn_sample((wdparm_t)priv);
#endif
}
/****************************************************************************
* Name: btn_sample
****************************************************************************/
static void btn_sample(wdparm_t arg)
{
FAR struct btn_upperhalf_s *priv;
FAR const struct btn_lowerhalf_s *lower;
FAR struct btn_open_s *opriv;
btn_buttonset_t sample;
btn_buttonset_t change;
btn_buttonset_t press;
btn_buttonset_t release;
priv = (FAR struct btn_upperhalf_s *)arg;
DEBUGASSERT(priv && priv->bu_lower);
lower = priv->bu_lower;
/* Sample the new button state */
DEBUGASSERT(lower->bl_buttons);
sample = lower->bl_buttons(lower);
add_ui_randomness(sample);
/* Determine which buttons have been newly pressed and which have been
* newly released.
*/
change = sample ^ priv->bu_sample;
press = change & sample;
DEBUGASSERT(lower->bl_supported);
release = change & (lower->bl_supported(lower) & ~sample);
/* Visit each opened reference to the device */
for (opriv = priv->bu_open; opriv; opriv = opriv->bo_flink)
{
/* Always set bo_pending true, only clear it after button read */
opriv->bo_pending = true;
/* Have any poll events occurred? */
if ((press & opriv->bo_pollevents.bp_press) != 0 ||
(release & opriv->bo_pollevents.bp_release) != 0)
{
/* Yes.. Notify all waiters */
poll_notify(opriv->bo_fds, CONFIG_INPUT_BUTTONS_NPOLLWAITERS,
POLLIN);
}
/* Have any signal events occurred? */
if ((press & opriv->bo_notify.bn_press) != 0 ||
(release & opriv->bo_notify.bn_release) != 0)
{
/* Yes.. Signal the waiter */
opriv->bo_notify.bn_event.sigev_value.sival_int = sample;
nxsig_notification(opriv->bo_pid, &opriv->bo_notify.bn_event,
SI_QUEUE, &opriv->bo_work);
}
}
priv->bu_sample = sample;
}
/****************************************************************************
* Name: btn_open
****************************************************************************/
static int btn_open(FAR struct file *filep)
{
FAR struct inode *inode;
FAR struct btn_upperhalf_s *priv;
FAR struct btn_open_s *opriv;
FAR const struct btn_lowerhalf_s *lower;
btn_buttonset_t supported;
irqstate_t flags;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Allocate a new open structure */
opriv = kmm_zalloc(sizeof(struct btn_open_s));
if (!opriv)
{
ierr("ERROR: Failed to allocate open structure\n");
return -ENOMEM;
}
/* Initialize the open structure */
lower = priv->bu_lower;
DEBUGASSERT(lower && lower->bl_supported);
flags = enter_critical_section();
supported = lower->bl_supported(lower);
opriv->bo_pollevents.bp_press = supported;
opriv->bo_pollevents.bp_release = supported;
opriv->bo_pending = true;
/* Attach the open structure to the device */
opriv->bo_flink = priv->bu_open;
priv->bu_open = opriv;
/* Attach the open structure to the file structure */
filep->f_priv = (FAR void *)opriv;
/* Enable/disable interrupt handling */
btn_enable(priv);
leave_critical_section(flags);
return OK;
}
/****************************************************************************
* Name: btn_close
****************************************************************************/
static int btn_close(FAR struct file *filep)
{
FAR struct inode *inode;
FAR struct btn_upperhalf_s *priv;
FAR struct btn_open_s *opriv;
FAR struct btn_open_s *curr;
FAR struct btn_open_s *prev;
irqstate_t flags;
DEBUGASSERT(filep->f_priv);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Get exclusive access to the driver structure */
flags = enter_critical_section();
#if CONFIG_INPUT_BUTTONS_DEBOUNCE_DELAY
wd_cancel(&priv->bu_wdog);
#endif
/* Find the open structure in the list of open structures for the device */
for (prev = NULL, curr = priv->bu_open;
curr && curr != opriv;
prev = curr, curr = curr->bo_flink);
DEBUGASSERT(curr);
if (!curr)
{
ierr("ERROR: Failed to find open entry\n");
leave_critical_section(flags);
return -ENOENT;
}
/* Remove the structure from the device */
if (prev)
{
prev->bo_flink = opriv->bo_flink;
}
else
{
priv->bu_open = opriv->bo_flink;
}
/* Enable/disable interrupt handling */
btn_enable(priv);
leave_critical_section(flags);
/* Cancel any pending notification */
nxsig_cancel_notification(&opriv->bo_work);
/* And free the open structure */
kmm_free(opriv);
return OK;
}
/****************************************************************************
* Name: btn_read
****************************************************************************/
static ssize_t btn_read(FAR struct file *filep, FAR char *buffer,
size_t len)
{
FAR struct inode *inode;
FAR struct btn_open_s *opriv;
FAR struct btn_upperhalf_s *priv;
FAR const struct btn_lowerhalf_s *lower;
irqstate_t flags;
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Make sure that the buffer is sufficiently large to hold at least one
* complete sample.
*
* REVISIT: Should also check buffer alignment.
*/
if (len < sizeof(btn_buttonset_t))
{
ierr("ERROR: buffer too small: %zu\n", len);
return -EINVAL;
}
/* Get exclusive access to the driver structure */
flags = enter_critical_section();
/* Read and return the current state of the buttons */
lower = priv->bu_lower;
DEBUGASSERT(lower && lower->bl_buttons);
*(FAR btn_buttonset_t *)buffer = lower->bl_buttons(lower);
opriv->bo_pending = false;
leave_critical_section(flags);
return (ssize_t)sizeof(btn_buttonset_t);
}
/****************************************************************************
* Name: btn_write
****************************************************************************/
static ssize_t btn_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
FAR struct inode *inode;
FAR struct btn_upperhalf_s *priv;
FAR const struct btn_lowerhalf_s *lower;
irqstate_t flags;
int ret;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Make sure that the buffer is sufficiently large to hold at least one
* complete sample.
*
* REVISIT: Should also check buffer alignment.
*/
if (buflen < sizeof(btn_buttonset_t))
{
ierr("ERROR: buffer too small: %zu\n", buflen);
return -EINVAL;
}
/* Get exclusive access to the driver structure */
flags = enter_critical_section();
/* Write the current state of the buttons */
lower = priv->bu_lower;
DEBUGASSERT(lower);
if (lower->bl_write)
{
ret = lower->bl_write(lower, buffer, buflen);
}
else
{
ret = -ENOSYS;
}
leave_critical_section(flags);
return (ssize_t)ret;
}
/****************************************************************************
* Name: btn_ioctl
****************************************************************************/
static int btn_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
FAR struct inode *inode;
FAR struct btn_upperhalf_s *priv;
FAR struct btn_open_s *opriv;
FAR const struct btn_lowerhalf_s *lower;
irqstate_t flags;
int ret = OK;
DEBUGASSERT(filep->f_priv);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Get exclusive access to the driver structure */
flags = enter_critical_section();
/* Handle the ioctl command */
ret = -EINVAL;
switch (cmd)
{
/* Command: BTNIOC_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 BTNIOC_SUPPORTED:
{
FAR btn_buttonset_t *supported =
(FAR btn_buttonset_t *)((uintptr_t)arg);
if (supported)
{
lower = priv->bu_lower;
DEBUGASSERT(lower && lower->bl_supported);
*supported = lower->bl_supported(lower);
ret = OK;
}
}
break;
/* Command: BTNIOC_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
* btn_pollevents_s
* Return: Zero (OK) on success. Minus one will be returned on
* failure with the errno value set appropriately.
*/
case BTNIOC_POLLEVENTS:
{
FAR struct btn_pollevents_s *pollevents =
(FAR struct btn_pollevents_s *)((uintptr_t)arg);
if (pollevents)
{
/* Save the poll events */
opriv->bo_pollevents.bp_press = pollevents->bp_press;
opriv->bo_pollevents.bp_release = pollevents->bp_release;
/* Enable/disable interrupt handling */
btn_enable(priv);
ret = OK;
}
}
break;
/* Command: BTNIOC_REGISTER
* Description: Register to receive a signal whenever there is a change
* in any of the discrete buttone inputs. This feature,
* of course, depends upon interrupt GPIO support from the
* platform.
* Argument: A read-only pointer to an instance of struct
* btn_notify_s
* Return: Zero (OK) on success. Minus one will be returned on
* failure with the errno value set appropriately.
*/
case BTNIOC_REGISTER:
{
FAR struct btn_notify_s *notify =
(FAR struct btn_notify_s *)((uintptr_t)arg);
if (notify)
{
/* Save the notification events */
opriv->bo_notify.bn_press = notify->bn_press;
opriv->bo_notify.bn_release = notify->bn_release;
opriv->bo_notify.bn_event = notify->bn_event;
opriv->bo_pid = nxsched_getpid();
/* Enable/disable interrupt handling */
btn_enable(priv);
ret = OK;
}
}
break;
default:
iinfo("ERROR: Unrecognized command: %d\n", cmd);
ret = -ENOTTY;
break;
}
leave_critical_section(flags);
return ret;
}
/****************************************************************************
* Name: btn_poll
****************************************************************************/
static int btn_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
FAR struct inode *inode;
FAR struct btn_upperhalf_s *priv;
FAR struct btn_open_s *opriv;
irqstate_t flags;
int ret = OK;
int i;
DEBUGASSERT(filep->f_priv);
opriv = filep->f_priv;
inode = filep->f_inode;
DEBUGASSERT(inode->i_private);
priv = inode->i_private;
/* Get exclusive access to the driver structure */
flags = enter_critical_section();
/* 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_INPUT_BUTTONS_NPOLLWAITERS; i++)
{
/* Find an available slot */
if (!opriv->bo_fds[i])
{
/* Bind the poll structure and this slot */
opriv->bo_fds[i] = fds;
fds->priv = &opriv->bo_fds[i];
/* Report if the event is pending */
if (opriv->bo_pending)
{
poll_notify(&fds, 1, POLLIN);
}
break;
}
}
if (i >= CONFIG_INPUT_BUTTONS_NPOLLWAITERS)
{
ierr("ERROR: Too many poll waiters\n");
fds->priv = NULL;
ret = -EBUSY;
goto errout;
}
}
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;
}
#endif
/* Remove all memory of the poll setup */
*slot = NULL;
fds->priv = NULL;
}
btn_enable(priv);
errout:
leave_critical_section(flags);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: btn_register
*
* Description:
* Bind the lower half button driver to an instance of the upper half
* button driver and register the composite character driver as the
* specified device.
*
* Input Parameters:
* devname - The name of the button device to be registered.
* This should be a string of the form "/dev/btnN" where N is the
* minor device number.
* lower - An instance of the platform-specific button 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 btn_register(FAR const char *devname,
FAR const struct btn_lowerhalf_s *lower)
{
FAR struct btn_upperhalf_s *priv;
int ret;
DEBUGASSERT(devname && lower);
/* Allocate a new button driver instance */
priv = (FAR struct btn_upperhalf_s *)
kmm_zalloc(sizeof(struct btn_upperhalf_s));
if (!priv)
{
ierr("ERROR: Failed to allocate device structure\n");
return -ENOMEM;
}
/* Make sure that all button interrupts are disabled */
DEBUGASSERT(lower->bl_enable);
lower->bl_enable(lower, 0, 0, NULL, NULL);
/* Initialize the new button driver instance */
priv->bu_lower = lower;
/* And register the button driver */
ret = register_driver(devname, &g_btn_fops, 0666, priv);
if (ret < 0)
{
ierr("ERROR: register_driver failed: %d\n", ret);
kmm_free(priv);
}
return ret;
}
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