/**************************************************************************** * drivers/1wire/1wire_read.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 "1wire_internal.h" /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: 1wire_read * * Description: * Receive a block of data from 1WIRE. Each read operation will be an * 'atomic' operation in the sense that any other 1WIRE actions will be * serialized and pend until this read completes. * * Input Parameters: * master - Device-specific state data * buffer - A pointer to a buffer of data to receive the data from the * device * buflen - The requested number of bytes to be read * * Returned Value: * 0: success, <0: A negated errno * ****************************************************************************/ int onewire_read(FAR struct onewire_master_s *master, FAR const struct onewire_config_s *config, FAR uint8_t *buffer, int buflen) { int ret; /* Avoid calling this function from a search callback to prevent a * deadlock */ if (master->insearch == true) { return -EAGAIN; } ret = nxrmutex_lock(&master->devlock); if (ret < 0) { return ret; } ret = onewire_reset_select(master, config->romcode); if (ret < 0) { goto err_unlock; } /* Then perform the transfer. */ ret = ONEWIRE_READ(master->dev, buffer, buflen); err_unlock: nxrmutex_unlock(&master->devlock); return ret; }