/**
******************************************************************************
* @addtogroup PIOS PIOS Core hardware abstraction layer
* @{
* @addtogroup   PIOS_RFM22B_RCVR RFM22B Receiver Input Functions
* @brief	 Code to output the PPM signal from the RFM22B
* @{
*
* @file       pios_rfm22b_rcvr.c
* @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
* @brief      Implements a receiver interface to the RFM22B device
* @see        The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_RFM22B_RCVR

#include "pios_rfm22b_priv.h"

/* Provide a RCVR driver */
static int32_t PIOS_RFM22B_RCVR_Get(uint32_t rcvr_id, uint8_t channel);
static void PIOS_RFM22B_RCVR_Supervisor(uint32_t rcvr_id);

const struct pios_rcvr_driver pios_rfm22b_rcvr_driver = {
    .read = PIOS_RFM22B_RCVR_Get,
};

/**
 * Initialize the receiver.
 *
 * @param[in] rfm22b_dev  The receiver ID.
 * @return < 0 on failure.
 */
int32_t PIOS_RFM22B_RCVR_Init(uint32_t rcvr_id)
{
    struct pios_rfm22b_dev *rfm22b_dev = (struct pios_rfm22b_dev *)rcvr_id;
    if (!PIOS_RFM22B_Validate(rfm22b_dev)) {
        return -1;
    }

    // Initialize
    for (uint8_t i = 0; i < PIOS_RFM22B_RCVR_MAX_CHANNELS; ++i) {
        rfm22b_dev->ppm_channel[i] = PIOS_RCVR_TIMEOUT;
    }
    rfm22b_dev->ppm_supv_timer = 0;

    // Register the failsafe timer callback.
    if (!PIOS_RTC_RegisterTickCallback(PIOS_RFM22B_RCVR_Supervisor, rcvr_id)) {
        PIOS_DEBUG_Assert(0);
    }

    return 0;
}

/**
 * Get a channel from the receiver.
 *
 * @param[in] rcvr_id  The receiver ID.
 * @return The channel value, or -1 on failure.
 */
static int32_t PIOS_RFM22B_RCVR_Get(uint32_t rcvr_id, uint8_t channel)
{
    struct pios_rfm22b_dev *rfm22b_dev = (struct pios_rfm22b_dev *)rcvr_id;
    if (!PIOS_RFM22B_Validate(rfm22b_dev)) {
        return -1;
    }

    if (channel >= GCSRECEIVER_CHANNEL_NUMELEM) {
        /* channel is out of range */
        return -1;
    }

    return rfm22b_dev->ppm_channel[channel];
}

/**
 * The supervisor function that ensures that the data is current.
 *
 * @param[in] rcvr_id  The receiver ID.
 */
static void PIOS_RFM22B_RCVR_Supervisor(uint32_t rcvr_id) {
    struct pios_rfm22b_dev *rfm22b_dev = (struct pios_rfm22b_dev *)rcvr_id;
    if (!PIOS_RFM22B_Validate(rfm22b_dev)) {
        return;
    }

    // RTC runs at 625Hz.
    if (++(rfm22b_dev->ppm_supv_timer) < (PIOS_RFM22B_RCVR_TIMEOUT_MS * 1000 / 625)) {
        return;
    }
    rfm22b_dev->ppm_supv_timer = 0;

    // Have we received fresh values since the last update?
    if (!rfm22b_dev->ppm_fresh) {
        for (uint8_t i = 0; i < PIOS_RFM22B_RCVR_MAX_CHANNELS; ++i) {
            rfm22b_dev->ppm_channel[i] = PIOS_RCVR_TIMEOUT;
        }
    }
    rfm22b_dev->ppm_fresh = false;
}

#endif	/* PIOS_INCLUDE_RFM22B_RCVR */

/** 
 * @}
 * @}
 */