/**************************************************************************** * drivers/sensors/usensor.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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define USENSOR_PATH "/dev/usensor" /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static int usensor_open(FAR struct file *filep); static int usensor_close(FAR struct file *filep); static ssize_t usensor_read(FAR struct file *filep, FAR char *buffer, size_t buflen); static ssize_t usensor_write(FAR struct file *filep, FAR const char *buffer, size_t buflen); static int usensor_ioctl(FAR struct file *filep, int cmd, unsigned long arg); /**************************************************************************** * Private Types ****************************************************************************/ /* This structure describes context of usensor */ struct usensor_context_s { sem_t exclsem; /* Manages exclusive access to file operations */ struct list_node list; /* List of node registered */ }; /* This structure describes lowerhalf driver for an usensor registered */ struct usensor_lowerhalf_s { struct list_node node; /* node in all usensor list */ struct sensor_lowerhalf_s driver; /* The lowerhalf driver of user sensor */ char path[1]; /* The path of usensor character device */ }; /**************************************************************************** * Private Data ****************************************************************************/ static const struct file_operations g_usensor_fops = { usensor_open, /* open */ usensor_close, /* close */ usensor_read, /* read */ usensor_write, /* write */ NULL, /* seek */ usensor_ioctl, /* ioctl */ NULL, /* poll */ }; static const struct sensor_ops_s g_usensor_ops = { }; /**************************************************************************** * Private Functions ****************************************************************************/ static int usensor_register(FAR struct usensor_context_s *usensor, FAR const struct sensor_reginfo_s *info) { FAR struct usensor_lowerhalf_s *lower; int ret; lower = kmm_zalloc(sizeof(*lower) + strlen(info->path)); if (!lower) { return -ENOMEM; } lower->driver.buffer_number = info->nqueue; lower->driver.ops = &g_usensor_ops; strcpy(lower->path, info->path); ret = sensor_custom_register(&lower->driver, lower->path, info->esize); if (ret < 0) { goto errout_with_lower; } ret = nxsem_wait(&usensor->exclsem); if (ret < 0) { goto errout_with_register; } list_add_tail(&usensor->list, &lower->node); nxsem_post(&usensor->exclsem); return ret; errout_with_register: sensor_custom_unregister(&lower->driver, info->path); errout_with_lower: kmm_free(lower); return ret; } static int usensor_unregister(FAR struct usensor_context_s *usensor, FAR const char *path) { FAR struct usensor_lowerhalf_s *lower; int ret; ret = nxsem_wait(&usensor->exclsem); if (ret < 0) { return ret; } list_for_every_entry(&usensor->list, lower, struct usensor_lowerhalf_s, node) { if (strcmp(path, lower->path) == 0) { list_delete(&lower->node); nxsem_post(&usensor->exclsem); sensor_custom_unregister(&lower->driver, path); kmm_free(lower); return 0; } } nxsem_post(&usensor->exclsem); return -ENOENT; } static int usensor_open(FAR struct file *filep) { return 0; } static int usensor_close(FAR struct file *filep) { return 0; } static ssize_t usensor_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { return buflen; } static ssize_t usensor_read(FAR struct file *filep, FAR char *buffer, size_t buflen) { return buflen; } static int usensor_ioctl(FAR struct file *filep, int cmd, unsigned long arg) { FAR struct inode *inode = filep->f_inode; FAR struct usensor_context_s *usensor = inode->i_private; int ret = -ENOTTY; if (cmd == SNIOC_REGISTER) { FAR const struct sensor_reginfo_s *info; info = (FAR const struct sensor_reginfo_s *)(uintptr_t)arg; ret = usensor_register(usensor, info); } else if (cmd == SNIOC_UNREGISTER) { FAR const char *path; path = (FAR const char *)(uintptr_t)arg; ret = usensor_unregister(usensor, path); } return ret; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: usensor_initialize * * Description: * This function registers usensor character node "/dev/usensor", so that * application can register user sensor by this node. The node will * manager all user sensors in this character dirver. ****************************************************************************/ int usensor_initialize(void) { FAR struct usensor_context_s *usensor; int ret; usensor = kmm_zalloc(sizeof(*usensor)); if (!usensor) { return -ENOMEM; } nxsem_init(&usensor->exclsem, 0, 1); list_initialize(&usensor->list); ret = register_driver(USENSOR_PATH, &g_usensor_fops, 0666, usensor); if (ret < 0) { goto errout_with_sem; } return ret; errout_with_sem: nxsem_destroy(&usensor->exclsem); kmm_free(usensor); return ret; }