/**************************************************************************** * drivers/djoystick.c * * Copyright (C) 2014, 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 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 #include #include #include #include #include #include #include #include #include #include #include #include /**************************************************************************** * 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: %d\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; }