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/****************************************************************************
* include/nuttx/qencoder.h
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
*
****************************************************************************/
#ifndef __NUTTX_SENSORS_QENCODER_H
#define __NUTTX_SENSORS_QENCODER_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/fs/ioctl.h>
#ifdef CONFIG_QENCODER
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
/* Configuration ************************************************************
* CONFIG_QENCODER - Enables support for the quadrature encoder upper half
*/
/* IOCTL Commands ***********************************************************/
/* The Quadrature Encode module uses a standard character driver framework.
* However, since the driver is a devices control interface and not a data
* transfer interface, the majority of the functionality is implemented in
* driver ioctl calls. The PWM ioctal commands are lised below:
*
* QEIOC_POSITION - Get the current position from the encoder.
* Argument: int32_t pointer to the location to return the position.
* QEIOC_RESET - Reset the position to zero.
* Argument: None
*/
#define QEIOC_POSITION _QEIOC(0x0001) /* Arg: int32_t* pointer */
#define QEIOC_RESET _QEIOC(0x0002) /* Arg: None */
/* User defined ioctl cms should use QEIOC_USER like this:
*
* #define QEIOC_MYCMD1 _QEIOC(QEIOC_USER)
* #define QEIOC_MYCMD2 _QEIOC(QEIOC_USER+1)
* ...
*/
#define QEIOC_USER 0x0003
/****************************************************************************
* Public Types
****************************************************************************/
/* This is the vtable that is used to by the upper half quadrature encoder
* to call back into the lower half quadrature encoder.
*/
struct qe_lowerhalf_s;
struct qe_ops_s
{
/* This method is called when the driver is opened. The lower half driver
* should configure and initialize the device so that it is ready for use.
* The initial position value should be zero.
*/
CODE int (*setup)(FAR struct qe_lowerhalf_s *lower);
/* This method is called when the driver is closed. The lower half driver
* should stop data collection, free any resources, disable timer hardware, and
* put the system into the lowest possible power usage state
*/
CODE int (*shutdown)(FAR struct qe_lowerhalf_s *lower);
/* Return the current position measurement. */
CODE int (*position)(FAR struct qe_lowerhalf_s *lower, int32_t *pos);
/* Reset the position measurement to zero. */
CODE int (*reset)(FAR struct qe_lowerhalf_s *lower);
/* Lower-half logic may support platform-specific ioctl commands */
CODE int (*ioctl)(FAR struct qe_lowerhalf_s *lower,
int cmd, unsigned long arg);
};
/* This is the interface between the lower half quadrature encoder driver
* and the upper half quadrature encoder driver. A (device-specific)
* instance of this structure is passed to the upper-half driver when the
* quadrature encoder driver is registered.
*
* Normally that lower half logic will have its own, custom state structure
* that is simply cast to struct qe_lowerhalf_s. In order to perform such casts,
* the initial fields of the custom state structure match the initial fields
* of the following generic lower half state structure.
*/
struct qe_lowerhalf_s
{
/* The first field of this state structure must be a pointer to the lower-
* half callback structure:
*/
FAR const struct qe_ops_s *ops;
/* The custom timer state structure may include additional fields after
* the pointer to the callback structure.
*/
};
/****************************************************************************
* Public Data
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* Name: qe_register
*
* Description:
* Register the Quadrature Encoder lower half device as 'devpath'
*
* Input Parameters:
* devpath - The full path to the driver to register. E.g., "/dev/qe0"
* lower - An instance of the lower half interface
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
****************************************************************************/
EXTERN int qe_register(FAR const char *devpath, FAR struct qe_lowerhalf_s *lower);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_QENCODER */
#endif /* __NUTTX_SENSORS_QENCODER_H */
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