text: /************************************************************************************
   * configs/sam3u-ek/src/sam_spi.c
   *
   *   Copyright (C) 2009, 2011, 2013 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 <stdint.h>
  #include <stdbool.h>
  #include <debug.h>
  #include <errno.h>
  
  #include <nuttx/spi/spi.h>
  #include <arch/board/board.h>
  
  #include "up_arch.h"
  #include "chip.h"
  #include "sam_gpio.h"
  #include "sam_spi.h"
  #include "sam3u-ek.h"
  
  #ifdef CONFIG_SAM34_SPI0
  
  /************************************************************************************
   * Public Functions
   ************************************************************************************/
  
  /************************************************************************************
   * Name: sam_spidev_initialize
   *
   * Description:
   *   Called to configure SPI chip select GPIO pins for the SAM3U-EK board.
   *
   ************************************************************************************/
  
  void weak_function sam_spidev_initialize(void)
  {
    /* The ZigBee module connects used NPCS0.  However, there is not yet any
     * ZigBee support.
     */
  
     /* The touchscreen connects using NPCS2 (PC14). */
  
  #if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_ADS7843E)
     sam_configgpio(GPIO_TSC_NPCS2);
  #endif
  }
  
  /****************************************************************************
   * Name:  sam_spi0select, sam_spi0status, and sam_spic0mddata
   *
   * Description:
   *   These external functions must be provided by board-specific logic.  They
   *   include:
   *
   *   o sam_spi0select is a functions tomanage the board-specific chip selects
   *   o sam_spi0status and sam_spic0mddata:  Implementations of the status
   *     and cmddata methods of the SPI interface defined by struct spi_ops_
   *     (see include/nuttx/spi/spi.h). All other methods including
   *     sam_spibus_initialize()) are provided by common SAM3/4 logic.
   *
   *  To use this common SPI logic on your board:
   *
   *   1. Provide logic in sam_boardinitialize() to configure SPI chip select
   *      pins.
   *   2. Provide sam_spi0select() and sam_spi0status() functions in your board-
   *      specific logic.  These functions will perform chip selection and
   *      status operations using GPIOs in the way your board is configured.
   *   2. If CONFIG_SPI_CMDDATA is defined in the NuttX configuration, provide
   *      sam_spic0mddata() functions in your board-specific logic.  This
   *      function will perform cmd/data selection operations using GPIOs in
   *      the way your board is configured.
   *   3. Add a call to sam_spibus_initialize() in your low level application
   *      initialization logic
   *   4. The handle returned by sam_spibus_initialize() may then be used to bind the
   *      SPI driver to higher level logic (e.g., calling
   *      mmcsd_spislotinitialize(), for example, will bind the SPI driver to
   *      the SPI MMC/SD driver).
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Name: sam_spi0select
   *
   * Description:
   *   PIO chip select pins may be programmed by the board specific logic in
   *   one of two different ways.  First, the pins may be programmed as SPI
   *   peripherals.  In that case, the pins are completely controlled by the
   *   SPI driver.  This method still needs to be provided, but it may be only
   *   a stub.
   *
   *   An alternative way to program the PIO chip select pins is as a normal
   *   GPIO output.  In that case, the automatic control of the CS pins is
   *   bypassed and this function must provide control of the chip select.
   *   NOTE:  In this case, the GPIO output pin does *not* have to be the
   *   same as the NPCS pin normal associated with the chip select number.
   *
   * Input Parameters:
   *   devid - Identifies the (logical) device
   *   selected - TRUE:Select the device, FALSE:De-select the device
   *
   * Returned Value:
   *   None
   *
   ****************************************************************************/
  
  void sam_spi0select(uint32_t devid, bool selected)
  {
    /* The touchscreen chip select is implemented as a GPIO OUTPUT that must
     * be controlled by this function.  This is because the ADS7843E driver
     * must be able to sample the device BUSY GPIO input between SPI transfers.
     * However, the AD7843E will tri-state the BUSY input whenever the chip
     * select is de-asserted.  So the only option is to control the chip select
     * manually and hold it low throughout the SPI transfer.
     */
  
  #if defined(CONFIG_INPUT) && defined(CONFIG_INPUT_ADS7843E)
    if (devid == SPIDEV_TOUCHSCREEN(0))
      {
        sam_gpiowrite(GPIO_TSC_NPCS2, !selected);
      }
  #endif
  }
  
  /****************************************************************************
   * Name: sam_spi0status
   *
   * Description:
   *   Return status information associated with the SPI device.
   *
   * Input Parameters:
   *   devid - Identifies the (logical) device
   *
   * Returned Value:
   *   Bit-encoded SPI status (see include/nuttx/spi/spi.h.
   *
   ****************************************************************************/
  
  uint8_t sam_spi0status(FAR struct spi_dev_s *dev, uint32_t devid)
  {
    return 0;
  }
  
  #endif /* CONFIG_SAM34_SPI0 */
  