nuttx/configs/stm32f4discovery/src/stm32_qencoder.c

/************************************************************************************
 * configs/stm32f4discovery/src/stm32_qencoder.c
 *
 *   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.
 *
 ************************************************************************************/

/************************************************************************************
 * Included Files
 ************************************************************************************/

#include <nuttx/config.h>

#include <errno.h>
#include <debug.h>

#include <nuttx/sensors/qencoder.h>
#include <arch/board/board.h>

#include "chip.h"
#include "up_arch.h"
#include "stm32_qencoder.h"
#include "stm32f4discovery.h"

/************************************************************************************
 * Pre-processor Definitions
 ************************************************************************************/
/* Configuration *******************************************************************/
/* Check if we have a timer configured for quadrature encoder -- assume YES. */

#define HAVE_QENCODER 1

/* If TIMn is not enabled (via CONFIG_STM32_TIMn), then the configuration cannot
 * specify TIMn as a quadrature encoder (via CONFIG_STM32_TIMn_QE).
 */

#ifndef CONFIG_STM32_TIM1
#  undef CONFIG_STM32_TIM1_QE
#endif
#ifndef CONFIG_STM32_TIM2
#  undef CONFIG_STM32_TIM2_QE
#endif
#ifndef CONFIG_STM32_TIM3
#  undef CONFIG_STM32_TIM3_QE
#endif
#ifndef CONFIG_STM32_TIM4
#  undef CONFIG_STM32_TIM4_QE
#endif
#ifndef CONFIG_STM32_TIM5
#  undef CONFIG_STM32_TIM5_QE
#endif
#ifndef CONFIG_STM32_TIM8
#  undef CONFIG_STM32_TIM8_QE
#endif

/* If the upper-half quadrature encoder driver is not enabled, then we cannot
 * support the quadrature encoder.
 */

#ifndef CONFIG_QENCODER
#  undef HAVE_QENCODER
#endif

/* Which Timer should we use, TIMID={1,2,3,4,5,8}.  If multiple timers are
 * configured as quadrature encoders, this logic will arbitrarily select
 * the lowest numbered timer.
 *
 * At least one TIMn, n={1,2,3,4,5,8}, must be both enabled and configured
 * as a quadrature encoder in order to support the lower half quadrature
 * encoder driver.  The above check assures that if CONFIG_STM32_TIMn_QE
 * is defined, then the correspdonding TIMn is also enabled.
 */

#if defined CONFIG_STM32_TIM1_QE
#  define TIMID 1
#elif defined CONFIG_STM32_TIM2_QE
#  define TIMID 2
#elif defined CONFIG_STM32_TIM3_QE
#  define TIMID 3
#elif defined CONFIG_STM32_TIM4_QE
#  define TIMID 4
#elif defined CONFIG_STM32_TIM5_QE
#  define TIMID 5
#elif defined CONFIG_STM32_TIM8_QE
#  define TIMID 8
#else
#  undef HAVE_QENCODER
#endif

#ifdef HAVE_QENCODER

/************************************************************************************
 * Public Functions
 ************************************************************************************/

/************************************************************************************
 * Name: qe_devinit
 *
 * Description:
 *   All STM32 architectures must provide the following interface to work with
 *   examples/qencoder.
 *
 ************************************************************************************/

int qe_devinit(void)
{
  static bool initialized = false;
  int ret;

  /* Check if we are already initialized */

  if (!initialized)
    {
      /* Initialize a quadrature encoder interface. */

      sninfo("Initializing the quadrature encoder using TIM%d\n", TIMID);
      ret = stm32_qeinitialize("/dev/qe0", TIMID);
      if (ret < 0)
        {
          snerr("ERROR: stm32_qeinitialize failed: %d\n", ret);
          return ret;
        }

      initialized = true;
    }

  return OK;
}

#endif /* HAVE_QENCODER */