/**************************************************************************** * drivers/sensors/zerocross.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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_SENSORS_ZEROCROSS /**************************************************************************** * Private Type Definitions ****************************************************************************/ /* This structure describes the state of the upper half driver */ struct zc_upperhalf_s { FAR struct zc_lowerhalf_s *lower; /* lower-half state */ sem_t exclsem; /* Supports mutual exclusion */ /* The following is a singly linked list of open references to the * zero cross device. */ FAR struct zc_open_s *zu_open; }; /* This structure describes the state of one open zero cross driver instance */ struct zc_open_s { /* Supports a singly linked list */ FAR struct zc_open_s *do_flink; /* The following will be true if we are closing */ volatile bool do_closing; /* Zero cross event notification information */ pid_t do_pid; struct sigevent do_event; struct sigwork_s do_work; }; /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static int zc_open(FAR struct file *filep); static int zc_close(FAR struct file *filep); static ssize_t zc_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t zc_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int zc_ioctl(FAR struct file *filep, int cmd, unsigned long arg); static void zerocross_enable(FAR struct zc_upperhalf_s *priv); static void zerocross_interrupt(FAR const struct zc_lowerhalf_s *lower, FAR void *arg); /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_zcops = { zc_open, /* open */ zc_close, /* close */ zc_read, /* read */ zc_write, /* write */ NULL, /* seek */ zc_ioctl, /* ioctl */ NULL /* poll */ #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS , 0 /* unlink */ #endif }; volatile int sample = 0; /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: zerocross_enable ****************************************************************************/ static void zerocross_enable(FAR struct zc_upperhalf_s *priv) { FAR const struct zc_lowerhalf_s *lower; irqstate_t flags; DEBUGASSERT(priv && priv->lower); lower = priv->lower; /* This routine is called both task level and interrupt level, so * interrupts must be disabled. */ flags = enter_critical_section(); /* Enable interrupts */ DEBUGASSERT(lower->zc_enable); /* Enable interrupts with the new button set */ lower->zc_enable(lower, (zc_interrupt_t)zerocross_interrupt, priv); leave_critical_section(flags); } /**************************************************************************** * Name: zerocross_interrupt ****************************************************************************/ static void zerocross_interrupt(FAR const struct zc_lowerhalf_s *lower, FAR void *arg) { FAR struct zc_upperhalf_s *priv = (FAR struct zc_upperhalf_s *)arg; FAR struct zc_open_s *opriv; irqstate_t flags; /* This routine is called both task level and interrupt level, so * interrupts must be disabled. */ flags = enter_critical_section(); /* Update sample value */ sample++; /* Visit each opened reference and notify a zero cross event */ for (opriv = priv->zu_open; opriv; opriv = opriv->do_flink) { /* Signal the waiter */ opriv->do_event.sigev_value.sival_int = sample; nxsig_notification(opriv->do_pid, &opriv->do_event, SI_QUEUE, &opriv->do_work); } leave_critical_section(flags); } /**************************************************************************** * Name: zc_open * * Description: * This function is called whenever the PWM device is opened. * ****************************************************************************/ static int zc_open(FAR struct file *filep) { FAR struct inode *inode; FAR struct zc_upperhalf_s *priv; FAR struct zc_open_s *opriv; int ret; DEBUGASSERT(filep && filep->f_inode); inode = filep->f_inode; DEBUGASSERT(inode->i_private); priv = (FAR struct zc_upperhalf_s *)inode->i_private; /* Get exclusive access to the driver structure */ ret = nxsem_wait(&priv->exclsem); if (ret < 0) { snerr("ERROR: nxsem_wait failed: %d\n", ret); return ret; } /* Allocate a new open structure */ opriv = (FAR struct zc_open_s *)kmm_zalloc(sizeof(struct zc_open_s)); if (!opriv) { snerr("ERROR: Failed to allocate open structure\n"); ret = -ENOMEM; goto errout_with_sem; } /* Attach the open structure to the device */ opriv->do_flink = priv->zu_open; priv->zu_open = opriv; /* Attach the open structure to the file structure */ filep->f_priv = (FAR void *)opriv; ret = OK; errout_with_sem: nxsem_post(&priv->exclsem); return ret; } /**************************************************************************** * Name: zc_close * * Description: * This function is called when the PWM device is closed. * ****************************************************************************/ static int zc_close(FAR struct file *filep) { FAR struct inode *inode; FAR struct zc_upperhalf_s *priv; FAR struct zc_open_s *opriv; FAR struct zc_open_s *curr; FAR struct zc_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 zc_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 zero cross 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 = nxsem_wait(&priv->exclsem); if (ret < 0) { snerr("ERROR: nxsem_wait failed: %d\n", ret); return ret; } /* Find the open structure in the list of open structures for the device */ for (prev = NULL, curr = priv->zu_open; curr && curr != opriv; prev = curr, curr = curr->do_flink); DEBUGASSERT(curr); if (!curr) { snerr("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->zu_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 */ zerocross_enable(priv); ret = OK; errout_with_exclsem: nxsem_post(&priv->exclsem); return ret; } /**************************************************************************** * Name: zc_read * * Description: * A dummy read method. This is provided only to satsify the VFS layer. * ****************************************************************************/ static ssize_t zc_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { /* Return zero -- usually meaning end-of-file */ return 0; } /**************************************************************************** * Name: zc_write * * Description: * A dummy write method. This is provided only to satsify the VFS layer. * ****************************************************************************/ static ssize_t zc_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { /* Return a failure */ return -EPERM; } /**************************************************************************** * Name: zc_ioctl * * Description: * The standard ioctl method. This is where ALL of the PWM work is done. * ****************************************************************************/ static int zc_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode; FAR struct zc_upperhalf_s *priv; FAR struct zc_open_s *opriv; int ret; sninfo("cmd: %d arg: %ld\n", cmd, arg); DEBUGASSERT(filep && filep->f_priv && filep->f_inode); opriv = filep->f_priv; inode = filep->f_inode; DEBUGASSERT(inode->i_private); priv = (FAR struct zc_upperhalf_s *)inode->i_private; /* Get exclusive access to the device structures */ ret = nxsem_wait(&priv->exclsem); if (ret < 0) { return ret; } /* Handle built-in ioctl commands */ ret = -EINVAL; switch (cmd) { /* Command: ZCIOC_REGISTER * Description: Register to receive a signal whenever there is zero * cross detection interrupt. * Argument: A read-only pointer to an instance of struct * zc_notify_s * Return: Zero (OK) on success. Minus one will be returned on * failure with the errno value set appropriately. */ case ZCIOC_REGISTER: { FAR struct sigevent *event = (FAR struct sigevent *)((uintptr_t)arg); if (event) { /* Save the notification events */ opriv->do_event = *event; opriv->do_pid = getpid(); /* Enable/disable interrupt handling */ zerocross_enable(priv); ret = OK; } } break; default: { snerr("ERROR: Unrecognized cmd: %d arg: %ld\n", cmd, arg); ret = -ENOTTY; } break; } nxsem_post(&priv->exclsem); return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: zc_register * * Description: * Register the Zero Cross character device as 'devpath' * * Input Parameters: * devpath - The full path to the driver to register. E.g., "/dev/zc0" * lower - An instance of the lower half interface * * Returned Value: * Zero (OK) on success; a negated errno value on failure. The following * possible error values may be returned (most are returned by * register_driver()): * * EINVAL - 'path' is invalid for this operation * EEXIST - An inode already exists at 'path' * ENOMEM - Failed to allocate in-memory resources for the operation * ****************************************************************************/ int zc_register(FAR const char *devname, FAR struct zc_lowerhalf_s *lower) { FAR struct zc_upperhalf_s *priv; int ret; DEBUGASSERT(devname && lower); /* Allocate a new zero cross driver instance */ priv = (FAR struct zc_upperhalf_s *) kmm_zalloc(sizeof(struct zc_upperhalf_s)); if (!priv) { snerr("ERROR: Failed to allocate device structure\n"); return -ENOMEM; } /* Make sure that zero cross interrupt is disabled */ DEBUGASSERT(lower->zc_enable); lower->zc_enable(lower, NULL, NULL); /* Initialize the new zero cross driver instance */ priv->lower = lower; nxsem_init(&priv->exclsem, 0, 1); /* And register the zero cross driver */ ret = register_driver(devname, &g_zcops, 0666, priv); if (ret < 0) { snerr("ERROR: register_driver failed: %d\n", ret); nxsem_destroy(&priv->exclsem); kmm_free(priv); } return ret; } #endif /* CONFIG_SENSORS_ZEROCROSS */