/**************************************************************************** * drivers/input/button_upper.c * * Copyright (C) 2015-2017 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 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 #include #include #include #include #include #include #include #include #include #include #include #include /**************************************************************************** * 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_enabled; /* Set of currently enabled button interrupts */ btn_buttonset_t bu_sample; /* Last sampled button states */ sem_t bu_exclsem; /* Supports exclusive access to the device */ /* The following is a singly linked list of open references to the * button device. */ FAR struct btn_open_s *bu_open; }; /* 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; /* The following will be true if we are closing */ volatile bool bo_closing; /* 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. */ FAR struct pollfd *bo_fds[CONFIG_BUTTONS_NPOLLWAITERS]; }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /* Semaphore helpers */ static inline int btn_takesem(sem_t *sem); #define btn_givesem(s) nxsem_post(s); /* 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(FAR struct btn_upperhalf_s *priv); /* 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 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 btn_fops = { btn_open, /* open */ btn_close, /* close */ btn_read, /* read */ NULL, /* write */ NULL, /* seek */ btn_ioctl, /* ioctl */ btn_poll /* poll */ }; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: btn_takesem ****************************************************************************/ static inline int btn_takesem(sem_t *sem) { int ret; /* Take a count from the semaphore, possibly waiting */ ret = nxsem_wait(sem); /* The only case that an error should occur here is if the wait * was awakened by a signal */ DEBUGASSERT(ret == OK || ret == -EINTR); return ret; } /**************************************************************************** * 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) { /* Enable interrupts with the new button set */ lower->bl_enable(lower, press, release, (btn_handler_t)btn_interrupt, priv); } else { /* 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 */ btn_sample(priv); } /**************************************************************************** * Name: btn_sample ****************************************************************************/ static void btn_sample(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; irqstate_t flags; int i; 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(); /* 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) { /* Have any poll events occurred? */ if ((press & opriv->bo_pollevents.bp_press) != 0 || (release & opriv->bo_pollevents.bp_release) != 0) { /* Yes.. Notify all waiters */ for (i = 0; i < CONFIG_BUTTONS_NPOLLWAITERS; i++) { FAR struct pollfd *fds = opriv->bo_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->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); } } /* Enable/disable interrupt handling */ btn_enable(priv); priv->bu_sample = sample; leave_critical_section(flags); } /**************************************************************************** * 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; int ret; DEBUGASSERT(filep && filep->f_inode); inode = filep->f_inode; DEBUGASSERT(inode->i_private); priv = (FAR struct btn_upperhalf_s *)inode->i_private; /* Get exclusive access to the driver structure */ ret = btn_takesem(&priv->bu_exclsem); if (ret < 0) { ierr("ERROR: btn_takesem failed: %d\n", ret); return ret; } /* Allocate a new open structure */ opriv = (FAR struct btn_open_s *)kmm_zalloc(sizeof(struct btn_open_s)); if (!opriv) { ierr("ERROR: Failled to allocate open structure\n"); ret = -ENOMEM; goto errout_with_sem; } /* Initialize the open structure */ lower = priv->bu_lower; DEBUGASSERT(lower && lower->bl_supported); supported = lower->bl_supported(lower); opriv->bo_pollevents.bp_press = supported; opriv->bo_pollevents.bp_release = supported; /* 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; ret = OK; /* Enable/disable interrupt handling */ btn_enable(priv); errout_with_sem: btn_givesem(&priv->bu_exclsem); return ret; } /**************************************************************************** * 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; 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 btn_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 button 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->bo_closing; opriv->bo_closing = true; leave_critical_section(flags); if (closing) { /* Another thread is doing the close */ return OK; } /* Get exclusive access to the driver structure */ ret = btn_takesem(&priv->bu_exclsem); if (ret < 0) { ierr("ERROR: btn_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->bu_open; curr && curr != opriv; prev = curr, curr = curr->bo_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->bo_flink = opriv->bo_flink; } else { priv->bu_open = opriv->bo_flink; } /* Cancel any pending notification */ nxsig_cancel_notification(&opriv->bo_work); /* And free the open structure */ kmm_free(opriv); /* Enable/disable interrupt handling */ btn_enable(priv); ret = OK; errout_with_exclsem: btn_givesem(&priv->bu_exclsem); return ret; } /**************************************************************************** * 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_upperhalf_s *priv; FAR const struct btn_lowerhalf_s *lower; int ret; DEBUGASSERT(filep && filep->f_inode); inode = filep->f_inode; DEBUGASSERT(inode->i_private); priv = (FAR struct btn_upperhalf_s *)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: %lu\n", (unsigned long)len); return -EINVAL; } /* Get exclusive access to the driver structure */ ret = btn_takesem(&priv->bu_exclsem); if (ret < 0) { ierr("ERROR: btn_takesem failed: %d\n", ret); return ret; } /* 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); btn_givesem(&priv->bu_exclsem); return (ssize_t)sizeof(btn_buttonset_t); } /**************************************************************************** * 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; 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 btn_upperhalf_s *)inode->i_private; /* Get exclusive access to the driver structure */ ret = btn_takesem(&priv->bu_exclsem); if (ret < 0) { ierr("ERROR: btn_takesem failed: %d\n", ret); return ret; } /* 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 = getpid(); /* Enable/disable interrupt handling */ btn_enable(priv); ret = OK; } } break; default: ierr("ERROR: Unrecognized command: %ld\n", cmd); ret = -ENOTTY; break; } btn_givesem(&priv->bu_exclsem); 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; 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 btn_upperhalf_s *)inode->i_private; /* Get exclusive access to the driver structure */ ret = btn_takesem(&priv->bu_exclsem); if (ret < 0) { ierr("ERROR: btn_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_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]; break; } } if (i >= CONFIG_BUTTONS_NPOLLWAITERS) { ierr("ERROR: Too many 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: btn_enable(priv); btn_givesem(&priv->bu_exclsem); 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; nxsem_init(&priv->bu_exclsem, 0, 1); DEBUGASSERT(lower->bl_buttons); priv->bu_sample = lower->bl_buttons(lower); /* And register the button driver */ ret = register_driver(devname, &btn_fops, 0666, priv); if (ret < 0) { ierr("ERROR: register_driver failed: %d\n", ret); goto errout_with_priv; } return OK; errout_with_priv: nxsem_destroy(&priv->bu_exclsem); kmm_free(priv); return ret; }