/*
    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio

    Licensed 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.
*/

/**
 * @file    ADCv1/hal_adc_lld.h
 * @brief   AVR/MEGA ADC subsystem low level driver header.
 *
 * @addtogroup ADC
 * @{
 */

#ifndef HAL_ADC_LLD_H
#define HAL_ADC_LLD_H

#if HAL_USE_ADC || defined(__DOXYGEN__)

/*==========================================================================*/
/* Driver constants.                                                        */
/*==========================================================================*/

#define ANALOG_REFERENCE_AREF   0
#define ANALOG_REFERENCE_AVCC   1
#define ANALOG_REFERENCE_1V1    2
#define ANALOG_REFERENCE_2V56   3

/*==========================================================================*/
/* Driver pre-compile time settings.                                        */
/*==========================================================================*/

/*==========================================================================*/
/* Derived constants and error checks.                                      */
/*==========================================================================*/

#if !CH_CFG_USE_SEMAPHORES
#error "the ADC driver requires CH_CFG_USE_SEMAPHORES"
#endif

/*==========================================================================*/
/* Driver data structures and types.                                        */
/*==========================================================================*/

/**
 * @brief   ADC sample data type.
 */
typedef uint16_t adcsample_t;

/**
 * @brief   Channels number in a conversion group.
 */
typedef uint16_t adc_channels_num_t;

/**
 * @brief   Type of a structure representing an ADC driver.
 */
typedef struct ADCDriver ADCDriver;

/**
 * @brief   ADC notification callback type.
 *
 * @param[in] adcp      pointer to the @p ADCDriver object triggering the
 *                      callback
 * @param[in] buffer    pointer to the most recent samples data
 * @param[in] n         number of buffer rows available starting from @p buffer
 */
typedef void (*adccallback_t)(ADCDriver *adcp, adcsample_t *buffer, size_t n);

/**
 * @brief   Conversion group configuration structure.
 * @details This implementation-dependent structure describes a conversion
 *          operation.
 * @note    Implementations may extend this structure to contain more,
 *          architecture dependent, fields.
 */
typedef struct {
  /**
   * @brief Enables the circular buffer mode for the group.
   */
  bool_t                    circular;
  /**
   * @brief Number of the analog channels belonging to the conversion group.
   */
  adc_channels_num_t        num_channels;
  /**
   * @brief Callback function associated to the group or @p NULL.
   */
  adccallback_t             end_cb;
  /* End of the mandatory fields.*/

  uint8_t                   channelsMask;

} ADCConversionGroup;

/**
 * @brief   Driver configuration structure.
 * @note    Implementations may extend this structure to contain more,
 *          architecture dependent, fields.
 * @note    It could be empty on some architectures.
 */
typedef struct {

  uint8_t analog_reference;

} ADCConfig;

/**
 * @brief   Structure representing an ADC driver.
 * @note    Implementations may extend this structure to contain more,
 *          architecture dependent, fields.
 */
struct ADCDriver {
  /**
   * @brief Driver state.
   */
  adcstate_t                state;
  /**
   * @brief Current configuration data.
   */
  const ADCConfig           *config;
  /**
   * @brief Current samples buffer pointer or @p NULL.
   */
  adcsample_t               *samples;
  /**
   * @brief Current samples buffer depth or @p 0.
   */
  size_t                    depth;
  /**
   * @brief Current conversion group pointer or @p NULL.
   */
  const ADCConversionGroup  *grpp;
#if ADC_USE_WAIT || defined(__DOXYGEN__)
  /**
   * @brief Waiting thread.
   */
  thread_reference_t        thread;
#endif /* ADC_USE_WAIT */
#if ADC_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__)
#if CH_CFG_USE_MUTEXES || defined(__DOXYGEN__)
  /**
   * @brief Mutex protecting the peripheral.
   */
  mutex_t                   mutex;
#elif CH_CFG_USE_SEMAPHORES
  Semaphore                 semaphore;
#endif
#endif /* ADC_USE_MUTUAL_EXCLUSION */
#if defined(ADC_DRIVER_EXT_FIELDS)
  ADC_DRIVER_EXT_FIELDS
#endif
  /* End of the mandatory fields.*/
  /**
   * @brief Current position in the buffer.
   */
  size_t currentBufferPosition;
};

/*==========================================================================*/
/* Driver macros.                                                           */
/*==========================================================================*/

/*==========================================================================*/
/* External declarations.                                                   */
/*==========================================================================*/

#if AVR_ADC_USE_ADC1 && !defined(__DOXYGEN__)
extern ADCDriver ADCD1;
#endif

#ifdef __cplusplus
extern "C" {
#endif
  void adc_lld_init(void);
  void adc_lld_start(ADCDriver *adcp);
  void adc_lld_stop(ADCDriver *adcp);
  void adc_lld_start_conversion(ADCDriver *adcp);
  void adc_lld_stop_conversion(ADCDriver *adcp);
#ifdef __cplusplus
}
#endif

#endif /* HAL_USE_ADC */

#endif /* HAL_ADC_LLD_H */

/** @} */