/*
 * SOES Simple Open EtherCAT Slave
 *
 * File    : esc_hw.c
 * Version : 0.9.2
 * Date    : 22-02-2010
 * Copyright (C) 2007-2013 Arthur Ketels
 * Copyright (C) 2012-2013 rt-labs
 *
 * SOES is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the Free
 * Software Foundation.
 *
 * SOES 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.
 *
 * As a special exception, if other files instantiate templates or use macros
 * or inline functions from this file, or you compile this file and link it
 * with other works to produce a work based on this file, this file does not
 * by itself cause the resulting work to be covered by the GNU General Public
 * License. However the source code for this file must still be made available
 * in accordance with section (3) of the GNU General Public License.
 *
 * This exception does not invalidate any other reasons why a work based on
 * this file might be covered by the GNU General Public License.
 *
 * The EtherCAT Technology, the trade name and logo "EtherCAT" are the intellectual
 * property of, and protected by Beckhoff Automation GmbH.
 */

 /** \file
 * \brief
 * ESC hardware layer functions.
 *
 * Function to read and write commands to the ESC. Used to read/write ESC
 * registers and memory.
 */

#include <cc.h>
#include <spi/spi.h>
#include <string.h>

#define ESC_CMD_READ    0x02
#define ESC_CMD_READWS  0x03
#define ESC_CMD_WRITE   0x04
#define ESC_CMD_NOP     0x00
#define ESC_TERM        0xff
#define ESC_NEXT        0x00

static int et1100 = -1;
static uint8 read_termination[128] = { 0 };

static void esc_address (uint16 address, uint8 command, uint16 * al_event)
{
   /* Device is selected already.
    * We use 2 bytes addressing.
    */
   uint8 data[2];

   /* address 12:5 */
   data[0] = (address >> 5);
   /* address 4:0 and cmd 2:0 */
   data[1] = ((address & 0x1F) << 3) | command;

   /* Write (and read AL interrupt register) */
   spi_bidirectionally_transfer (et1100, (uint8 *) al_event, data,
                                 sizeof (data));
}

/** ESC read function used by the Slave stack.
 *
 * @param[in]   address     = address of ESC register to read
 * @param[out]  buf         = pointer to buffer to read in
 * @param[in]   len         = number of bytes to read
 * @param[out]  tALevent    = on every read we refresh the AL event register
 * @return 0 as default, the stack don't rely on any result
 */
uint8 ESC_read (uint16 address, void *buf, uint16 len, void *tALevent)
{
   /* Select device. */
   spi_select (et1100);

   /* Write address and command to device. */
   esc_address (address, ESC_CMD_READ, tALevent);

   /* Here we want to read data and keep MOSI low (0x00) during
    * all bytes except the last one where we want to pull it high (0xFF).
    * Read (and write termination bytes).
    */
   spi_bidirectionally_transfer (et1100, buf, read_termination + (128 - len),
                                 len);

   /* Un-select device. */
   spi_unselect (et1100);
   /* result is never used */
   return 0;
}

/** ESC write function used by the Slave stack.
 *
 * @param[in]   address     = address of ESC register to write
 * @param[out]  buf         = pointer to buffer to write from
 * @param[in]   len         = number of bytes to write
 * @param[out]  tALevent    = on every read we refresh the AL event register
 * @return 0 as default, the stack don't rely on any result
 */
uint8 ESC_write (uint16 address, void *buf, uint16 len, void *tALevent)
{
   /* Select device. */
   spi_select (et1100);
   /* Write address and command to device. */
   esc_address (address, ESC_CMD_WRITE, tALevent);
   /* Write data. */
   write (et1100, buf, len);
   /* Un-select device. */
   spi_unselect (et1100);
   /* result is never used */
   return 0;
}

void ESC_init (void * arg)
{
   char * spi_name = (char *)arg;
   et1100 = open (spi_name, O_RDWR, 0);
   read_termination[127] = 0xFF;
}