100 lines
3.8 KiB
C
100 lines
3.8 KiB
C
/****************************************************************************
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* include/nuttx/ioexpander/pcf8574.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __INCLUDE_NUTTX_IOEXPANDER_PCF8574_H
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#define __INCLUDE_NUTTX_IOEXPANDER_PCF8574_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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/****************************************************************************
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* Public Types
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****************************************************************************/
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#ifdef CONFIG_PCF8574_INT_ENABLE
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/* This is the type of the PCF8574xx interrupt handler */
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typedef CODE void (*pcf8574_handler_t)(FAR void *arg);
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#endif
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/* A reference to a structure of this type must be passed to the PCF8574xx
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* driver when the driver is instantiated. This structure provides
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* information about the configuration of the PCF8574xx and provides some
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* board-specific hooks.
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*
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* Memory for this structure is provided by the caller. It is not copied by
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* the driver and is presumed to persist while the driver is active. The
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* memory must be writeable because, under certain circumstances, the driver
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* may modify the frequency.
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*/
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struct pcf8574_config_s
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{
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/* Device characterization */
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uint8_t address; /* 7-bit I2C address (only bits 0-6 used) */
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uint32_t frequency; /* I2C frequency */
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#ifdef CONFIG_PCF8574_INT_ENABLE
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/* IRQ/GPIO access callbacks. These operations all hidden behind
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* callbacks to isolate the PCF8574xx driver from differences in GPIO
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* interrupt handling by varying boards and MCUs.
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*
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* attach - Attach the PCF8574xx interrupt handler to the GPIO interrupt
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* enable - Enable or disable the GPIO interrupt
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*/
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CODE int (*attach)(FAR struct pcf8574_config_s *state,
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pcf8574_handler_t handler, FAR void *arg);
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CODE void (*enable)(FAR struct pcf8574_config_s *state, bool enable);
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#endif
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};
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: pcf8574_initialize
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*
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* Description:
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* Instantiate and configure the PCF8574xx device driver to use the
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* provided I2C device instance.
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*
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* Input Parameters:
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* i2c - An I2C driver instance
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* minor - The device i2c address
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* config - Persistent board configuration data
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*
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* Returned Value:
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* an ioexpander_dev_s instance on success, NULL on failure.
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*
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****************************************************************************/
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struct i2c_master_s;
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FAR struct ioexpander_dev_s *pcf8574_initialize(FAR struct i2c_master_s *i2c,
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FAR struct pcf8574_config_s *config);
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#endif /* __INCLUDE_NUTTX_IOEXPANDER_PCF8574_H */
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