max1168.c

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/*
 * Copyright (C) 2008-2009 Antoine Drouin <poinix@gmail.com>
 * Copyright (C) 2012 Gautier Hattenberger
 *
 * This file is part of paparazzi.
 *
 * paparazzi 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 2, or (at your option)
 * any later version.
 *
 * paparazzi 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 paparazzi; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 */
 
#include "peripherals/max1168.h"
#include "mcu_periph/spi.h"
 
volatile uint8_t max1168_status;
uint16_t max1168_values[MAX1168_NB_CHAN];
 
struct spi_transaction max1168_req_trans;
struct spi_transaction max1168_read_trans;
 
uint16_t max1168_conv_req;
 
/* callback function to lock the spi fifo
 * after the first transaction
 */
void max1168_lock_cb(struct spi_transaction *t);
 
extern void max1168_init(void)
{
 
  max1168_arch_init();
 
  uint8_t i;
  for (i = 0; i < MAX1168_NB_CHAN; i++) {
    max1168_values[i] = 0;
  }
 
  // init spi transaction parameters
  max1168_req_trans.cpol = SPICpolIdleLow;
  max1168_req_trans.cpha = SPICphaEdge1;
  max1168_req_trans.dss = SPIDss16bit;
  max1168_req_trans.bitorder = SPIMSBFirst;
  max1168_req_trans.cdiv = SPIDiv64;
 
  max1168_req_trans.slave_idx = MAX1168_SLAVE_IDX;
  max1168_req_trans.select = SPISelect;
  max1168_conv_req = MAX1168_CONF_CR << 8;
  max1168_req_trans.output_buf = (uint8_t *)(&max1168_conv_req);
  max1168_req_trans.output_length = 1;
  max1168_req_trans.input_buf = NULL;
  max1168_req_trans.input_length = 0;
  max1168_req_trans.after_cb = max1168_lock_cb;
  max1168_req_trans.status = SPITransDone;
 
  max1168_read_trans.cpol = SPICpolIdleLow;
  max1168_read_trans.cpha = SPICphaEdge1;
  max1168_read_trans.dss = SPIDss16bit;
  max1168_read_trans.bitorder = SPIMSBFirst;
  max1168_read_trans.cdiv = SPIDiv64;
 
  max1168_read_trans.slave_idx = MAX1168_SLAVE_IDX;
  max1168_read_trans.select = SPIUnselect;
  // read 8 16bit frames
  // FIXME should be function of control register options
  max1168_read_trans.output_buf = NULL;
  max1168_read_trans.output_length = 0;
  max1168_read_trans.input_buf = (uint8_t *)max1168_values;
  max1168_read_trans.input_length = 8;
  max1168_read_trans.status = SPITransDone;
 
  max1168_status = MAX1168_IDLE;
}
 
#include "led.h"
void max1168_read(void)
{
  //ASSERT((max1168_status == MAX1168_IDLE), DEBUG_MAX_1168, MAX1168_ERR_READ_OVERUN);
 
  /* set SPI transaction */
  /* SPI is locked between the two transactions (callback) */
  /* SPI is unlocked when EOC is received */
 
  spi_submit(&(MAX1168_SPI_DEV), &max1168_req_trans);
  spi_submit(&(MAX1168_SPI_DEV), &max1168_read_trans);
 
  max1168_status = MAX1168_SENDING_REQ;
}
 
void max1168_event(void)
{
  // handle request transaction
  if (max1168_req_trans.status == SPITransSuccess) {
    max1168_req_trans.status = SPITransDone;
  } else if (max1168_req_trans.status == SPITransFailed) {
    max1168_status = MAX1168_IDLE;
    spi_slave_unselect(MAX1168_SLAVE_IDX);
    spi_resume(&(MAX1168_SPI_DEV), MAX1168_SLAVE_IDX);
    max1168_req_trans.status = SPITransDone;
  }
 
  // handle reading transaction
  if (max1168_read_trans.status == SPITransSuccess) {
    if (max1168_status == MAX1168_READING_RES) {
      // result was already written to max1168_values by DMA
      max1168_status = MAX1168_DATA_AVAILABLE;
      max1168_read_trans.status = SPITransDone;
    }
  } else if (max1168_read_trans.status == SPITransFailed) {
    max1168_status = MAX1168_IDLE;
    spi_slave_unselect(MAX1168_SLAVE_IDX);
    max1168_read_trans.status = SPITransDone;
  }
  // Waiting for EOC
  // FIXME possible race condition, should suspend external int ?
  if (max1168_status == MAX1168_GOT_EOC) {
    // eoc occurs, unlock SPI
    spi_resume(&(MAX1168_SPI_DEV), MAX1168_SLAVE_IDX);
    max1168_status = MAX1168_READING_RES;
  }
}
 
void max1168_lock_cb(struct spi_transaction *t __attribute__((unused)))
{
  spi_lock(&(MAX1168_SPI_DEV), MAX1168_SLAVE_IDX);
}