181 lines
6.5 KiB
C
181 lines
6.5 KiB
C
/****************************************************************************
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* include/nuttx/qencoder.h
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*
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* Copyright (C) 2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __NUTTX_SENSORS_QENCODER_H
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#define __NUTTX_SENSORS_QENCODER_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 <nuttx/fs/ioctl.h>
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#ifdef CONFIG_QENCODER
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/****************************************************************************
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* Pre-Processor Definitions
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****************************************************************************/
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/* Configuration ************************************************************
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* CONFIG_QENCODER - Enables support for the quadrature encoder upper half
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*/
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/* IOCTL Commands ***********************************************************/
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/* The Quadrature Encode module uses a standard character driver framework.
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* However, since the driver is a devices control interface and not a data
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* transfer interface, the majority of the functionality is implemented in
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* driver ioctl calls. The PWM ioctal commands are lised below:
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*
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* QEIOC_POSITION - Get the current position from the encoder.
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* Argument: int32_t pointer to the location to return the position.
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* QEIOC_RESET - Reset the position to zero.
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* Argument: None
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*/
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#define QEIOC_POSITION _QEIOC(0x0001) /* Arg: int32_t* pointer */
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#define QEIOC_RESET _QEIOC(0x0002) /* Arg: None */
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/* User defined ioctl cms should use QEIOC_USER like this:
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*
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* #define QEIOC_MYCMD1 _QEIOC(QEIOC_USER)
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* #define QEIOC_MYCMD2 _QEIOC(QEIOC_USER+1)
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* ...
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*/
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#define QEIOC_USER 0x0003
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* This is the vtable that is used to by the upper half quadrature encoder
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* to call back into the lower half quadrature encoder.
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*/
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struct qe_lowerhalf_s;
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struct qe_ops_s
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{
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/* This method is called when the driver is opened. The lower half driver
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* should configure and initialize the device so that it is ready for use.
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* The initial position value should be zero.
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*/
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CODE int (*setup)(FAR struct qe_lowerhalf_s *lower);
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/* This method is called when the driver is closed. The lower half driver
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* should stop data collection, free any resources, disable timer hardware, and
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* put the system into the lowest possible power usage state
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*/
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CODE int (*shutdown)(FAR struct qe_lowerhalf_s *lower);
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/* Return the current position measurement. */
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CODE int (*position)(FAR struct qe_lowerhalf_s *lower, int32_t *pos);
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/* Reset the position measurement to zero. */
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CODE int (*reset)(FAR struct qe_lowerhalf_s *lower);
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/* Lower-half logic may support platform-specific ioctl commands */
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CODE int (*ioctl)(FAR struct qe_lowerhalf_s *lower,
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int cmd, unsigned long arg);
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};
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/* This is the interface between the lower half quadrature encoder driver
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* and the upper half quadrature encoder driver. A (device-specific)
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* instance of this structure is passed to the upper-half driver when the
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* quadrature encoder driver is registered.
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*
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* Normally that lower half logic will have its own, custom state structure
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* that is simply cast to struct qe_lowerhalf_s. In order to perform such casts,
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* the initial fields of the custom state structure match the initial fields
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* of the following generic lower half state structure.
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*/
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struct qe_lowerhalf_s
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{
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/* The first field of this state structure must be a pointer to the lower-
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* half callback structure:
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*/
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FAR const struct qe_ops_s *ops;
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/* The custom timer state structure may include additional fields after
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* the pointer to the callback structure.
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*/
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};
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/****************************************************************************
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* Public Data
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****************************************************************************/
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#ifdef __cplusplus
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#define EXTERN extern "C"
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extern "C" {
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#else
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#define EXTERN extern
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#endif
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Name: qe_register
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*
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* Description:
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* Register the Quadrature Encoder lower half device as 'devpath'
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*
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* Input Parameters:
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* devpath - The full path to the driver to register. E.g., "/dev/qe0"
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* lower - An instance of the lower half interface
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*
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* Returned Value:
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* Zero (OK) on success; a negated errno value on failure.
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*
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****************************************************************************/
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EXTERN int qe_register(FAR const char *devpath, FAR struct qe_lowerhalf_s *lower);
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* CONFIG_QENCODER */
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#endif /* __NUTTX_SENSORS_QENCODER_H */
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