text: /****************************************************************************
   * boards/arm/sam34/sam3u-ek/src/sam_touchscreen.c
   *
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.  The
   * ASF licenses this file to you 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.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <stdbool.h>
  #include <stdio.h>
  #include <debug.h>
  #include <assert.h>
  #include <errno.h>
  
  #include <nuttx/board.h>
  #include <nuttx/spi/spi.h>
  #include <nuttx/input/touchscreen.h>
  #include <nuttx/input/ads7843e.h>
  
  #include "sam_gpio.h"
  #include "sam_spi.h"
  
  #include "sam3u-ek.h"
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  /* Configuration ************************************************************/
  
  #ifdef CONFIG_INPUT_ADS7843E
  #ifndef CONFIG_INPUT
  #  error "Touchscreen support requires CONFIG_INPUT"
  #endif
  
  #ifndef CONFIG_SAM34_SPI0
  #  error "Touchscreen support requires CONFIG_SAM34_SPI0"
  #endif
  
  #ifndef CONFIG_SAM34_GPIOA_IRQ
  #  error "Touchscreen support requires CONFIG_SAM34_GPIOA_IRQ"
  #endif
  
  #ifndef CONFIG_ADS7843E_FREQUENCY
  #  define CONFIG_ADS7843E_FREQUENCY 500000
  #endif
  
  #ifndef CONFIG_ADS7843E_SPIDEV
  #  define CONFIG_ADS7843E_SPIDEV TSC_CSNUM
  #endif
  
  #if CONFIG_ADS7843E_SPIDEV != TSC_CSNUM
  #  error "CONFIG_ADS7843E_SPIDEV must have the same value as TSC_CSNUM"
  #endif
  
  #ifndef CONFIG_ADS7843E_DEVMINOR
  #  define CONFIG_ADS7843E_DEVMINOR 0
  #endif
  
  /****************************************************************************
   * Static Function Prototypes
   ****************************************************************************/
  
  /* IRQ/GPIO access callbacks.  These operations all hidden behind
   * callbacks to isolate the ADS7843E driver from differences in GPIO
   * interrupt handling by varying boards and MCUs.  If possible,
   * interrupts should be configured on both rising and falling edges
   * so that contact and loss-of-contact events can be detected.
   *
   * attach  - Attach the ADS7843E interrupt handler to the GPIO interrupt
   * enable  - Enable or disable the GPIO interrupt
   * clear   - Acknowledge/clear any pending GPIO interrupt
   * pendown - Return the state of the pen down GPIO input
   */
  
  static int  tsc_attach(struct ads7843e_config_s *state, xcpt_t isr);
  static void tsc_enable(struct ads7843e_config_s *state, bool enable);
  static void tsc_clear(struct ads7843e_config_s *state);
  static bool tsc_busy(struct ads7843e_config_s *state);
  static bool tsc_pendown(struct ads7843e_config_s *state);
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  /* A reference to a structure of this type must be passed to the ADS7843E
   * driver.  This structure provides information about the configuration
   * of the ADS7843E and provides some board-specific hooks.
   *
   * Memory for this structure is provided by the caller.  It is not copied
   * by the driver and is presumed to persist while the driver is active. The
   * memory must be writable because, under certain circumstances, the driver
   * may modify frequency or X plate resistance values.
   */
  
  static struct ads7843e_config_s g_tscinfo =
  {
    .frequency = CONFIG_ADS7843E_FREQUENCY,
  
    .attach    = tsc_attach,
    .enable    = tsc_enable,
    .clear     = tsc_clear,
    .busy      = tsc_busy,
    .pendown   = tsc_pendown,
  };
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /* IRQ/GPIO access callbacks.  These operations all hidden behind
   * callbacks to isolate the ADS7843E driver from differences in GPIO
   * interrupt handling by varying boards and MCUs.  If possible,
   * interrupts should be configured on both rising and falling edges
   * so that contact and loss-of-contact events can be detected.
   *
   * attach  - Attach the ADS7843E interrupt handler to the GPIO interrupt
   * enable  - Enable or disable the GPIO interrupt
   * clear   - Acknowledge/clear any pending GPIO interrupt
   * pendown - Return the state of the pen down GPIO input
   */
  
  static int tsc_attach(struct ads7843e_config_s *state, xcpt_t isr)
  {
    /* Attach the ADS7843E interrupt */
  
    iinfo("Attaching %p to IRQ %d\n", isr, SAM_TCS_IRQ);
    return irq_attach(SAM_TCS_IRQ, isr, NULL);
  }
  
  static void tsc_enable(struct ads7843e_config_s *state, bool enable)
  {
    /* Attach and enable, or detach and disable */
  
    iinfo("IRQ:%d enable:%d\n", SAM_TCS_IRQ, enable);
    if (enable)
      {
        sam_gpioirqenable(SAM_TCS_IRQ);
      }
    else
      {
        sam_gpioirqdisable(SAM_TCS_IRQ);
      }
  }
  
  static void tsc_clear(struct ads7843e_config_s *state)
  {
    /* Does nothing */
  }
  
  static bool tsc_busy(struct ads7843e_config_s *state)
  {
  #if defined(CONFIG_DEBUG_INPUT) && defined(CONFIG_DEBUG_INFO)
    static bool last = (bool)-1;
  #endif
  
    /* BUSY is high impedance when CS is high (not selected).  When CS is
     * is low, BUSY is active high.
     */
  
    bool busy = sam_gpioread(GPIO_TCS_BUSY);
  #if defined(CONFIG_DEBUG_INPUT) && defined(CONFIG_DEBUG_INFO)
    if (busy != last)
      {
        iinfo("busy:%d\n", busy);
        last = busy;
      }
  #endif
  
    return busy;
  }
  
  static bool tsc_pendown(struct ads7843e_config_s *state)
  {
    /* The /PENIRQ value is active low */
  
    bool pendown = !sam_gpioread(GPIO_TCS_IRQ);
    iinfo("pendown:%d\n", pendown);
    return pendown;
  }
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: sam_tsc_setup
   *
   * Description:
   *   This function is called by board-bringup logic to configure the
   *   touchscreen device.  This function will register the driver as
   *   /dev/inputN where N is the minor device number.
   *
   * Input Parameters:
   *   minor   - The input device minor number
   *
   * Returned Value:
   *   Zero is returned on success.  Otherwise, a negated errno value is
   *   returned to indicate the nature of the failure.
   *
   ****************************************************************************/
  
  int sam_tsc_setup(int minor)
  {
    struct spi_dev_s *dev;
    int ret;
  
    iinfo("minor %d\n", minor);
    DEBUGASSERT(minor == 0);
  
    /* Configure and enable the ADS7843E interrupt pin as an input */
  
    sam_configgpio(GPIO_TCS_BUSY);
    sam_configgpio(GPIO_TCS_IRQ);
  
    /* Configure the PIO interrupt */
  
    sam_gpioirq(GPIO_TCS_IRQ);
  
    /* Get an instance of the SPI interface for the touchscreen chip select */
  
    dev = sam_spibus_initialize(TSC_CSNUM);
    if (!dev)
      {
        ierr("ERROR: Failed to initialize SPI chip select %d\n", TSC_CSNUM);
        return -ENODEV;
      }
  
    /* Initialize and register the SPI touschscreen device */
  
    ret = ads7843e_register(dev, &g_tscinfo, CONFIG_ADS7843E_DEVMINOR);
    if (ret < 0)
      {
        ierr("ERROR: Failed to initialize SPI chip select %d\n", TSC_CSNUM);
  
        /* sam_spibus_uninitialize(dev); */
  
        return -ENODEV;
      }
  
    return OK;
  }
  
  #endif /* CONFIG_INPUT_ADS7843E */
  