/****************************************************************************
 * arch/risc-v/src/fe310/fe310_gpio.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 <stdint.h>
#include <assert.h>
#include <debug.h>

#include <nuttx/arch.h>
#include <nuttx/spinlock.h>
#include <arch/board/board.h>

#include "riscv_internal.h"
#include "fe310_gpio.h"
#include "fe310_memorymap.h"

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name:  fe310_gpio_getpin()
 ****************************************************************************/

static uint32_t fe310_gpio_getpin(uint16_t gpiocfg)
{
  return ((gpiocfg & GPIO_PIN_MASK) >> GPIO_PIN_SHIFT);
}

/****************************************************************************
 * Name:  fe310_gpio_configinput()
 ****************************************************************************/

static int fe310_gpio_configinput(uint16_t gpiocfg)
{
  uint32_t pin  = fe310_gpio_getpin(gpiocfg);

  /* Enable input & disable output */

  modifyreg32(FE310_GPIO_INPUT_EN, 0, 0x1 << pin);
  modifyreg32(FE310_GPIO_OUTPUT_EN, 0x1 << pin, 0);
  return 0;
}

/****************************************************************************
 * Name:  fe310_gpio_configirq()
 ****************************************************************************/

static int fe310_gpio_configirq(uint16_t gpiocfg)
{
  uint32_t pin  = fe310_gpio_getpin(gpiocfg);

  /* Enable input & disable output */

  modifyreg32(FE310_GPIO_INPUT_EN, 0, 0x1 << pin);
  modifyreg32(FE310_GPIO_OUTPUT_EN, 0x1 << pin, 0);

  /* Disable all gpio interrupts for the pin */

  modifyreg32(FE310_GPIO_RISE_IE, 0x1 << pin, 0x0);
  modifyreg32(FE310_GPIO_FALL_IE, 0x1 << pin, 0x0);
  modifyreg32(FE310_GPIO_HIGH_IE, 0x1 << pin, 0x0);
  modifyreg32(FE310_GPIO_LOW_IE,  0x1 << pin, 0x0);

  /* Then enable interrupt */

  switch (gpiocfg & GPIO_INT_MASK)
    {
      case GPIO_INT_RISE:
        modifyreg32(FE310_GPIO_RISE_IE, 0, 0x1 << pin);
        break;

      case GPIO_INT_FALL:
        modifyreg32(FE310_GPIO_FALL_IE, 0, 0x1 << pin);
        break;

      case GPIO_INT_BOTH:
        modifyreg32(FE310_GPIO_RISE_IE, 0, 0x1 << pin);
        modifyreg32(FE310_GPIO_FALL_IE, 0, 0x1 << pin);
        break;

      case GPIO_INT_HIGH:
        modifyreg32(FE310_GPIO_HIGH_IE, 0, 0x1 << pin);
        break;

      case GPIO_INT_LOW:
        modifyreg32(FE310_GPIO_LOW_IE, 0, 0x1 << pin);
        break;
    }

  return 0;
}

/****************************************************************************
 * Name:  fe310_gpio_configoutput()
 ****************************************************************************/

static int fe310_gpio_configoutput(uint16_t gpiocfg)
{
  uint32_t pin  = fe310_gpio_getpin(gpiocfg);

  /* TOD: set initial value */

  /* Disable input & enable output */

  modifyreg32(FE310_GPIO_INPUT_EN, 0x1 << pin, 0);
  modifyreg32(FE310_GPIO_OUTPUT_EN, 0, 0x1 << pin);
  return 0;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: fe310_gpio_config
 ****************************************************************************/

int fe310_gpio_config(uint16_t gpiocfg)
{
  int ret = 0;
  irqstate_t flags;

  uint32_t pin  = fe310_gpio_getpin(gpiocfg);

  flags = spin_lock_irqsave(NULL);

  /* Disable IOF for the pin to be used as GPIO */

  modifyreg32(FE310_GPIO_IOF_EN, 0x1 << pin, 0);

  /* Pullup */

  if (gpiocfg & GPIO_PULLUP)
    {
      modifyreg32(FE310_GPIO_PU_EN, 0, 0x1 << pin);
    }
  else
    {
      modifyreg32(FE310_GPIO_PU_EN, 0x1 << pin, 0);
    }

  switch (gpiocfg & GPIO_MODE_MASK)
    {
      case GPIO_MODE_INPUT:

        ret = fe310_gpio_configinput(gpiocfg);
        break;

      case GPIO_MODE_OUTPUT:

        ret = fe310_gpio_configoutput(gpiocfg);
        break;

      case GPIO_MODE_INIRQ:

        ret = fe310_gpio_configirq(gpiocfg);
        break;
    }

  spin_unlock_irqrestore(NULL, flags);

  return ret;
}

/****************************************************************************
 * Name: fe310_gpio_write
 ****************************************************************************/

void fe310_gpio_write(uint16_t gpiocfg, bool value)
{
  uint32_t pin  = fe310_gpio_getpin(gpiocfg);

  if (value)
    {
      modifyreg32(FE310_GPIO_OUTPUT_VAL, 0, 0x1 << pin);
    }
  else
    {
      modifyreg32(FE310_GPIO_OUTPUT_VAL, 0x1 << pin, 0);
    }
}

/****************************************************************************
 * Name: fe310_gpio_read
 ****************************************************************************/

bool fe310_gpio_read(uint16_t gpiocfg)
{
  uint32_t pin  = fe310_gpio_getpin(gpiocfg);
  return (getreg32(FE310_GPIO_INPUT_VAL) & (0x1 << pin)) != 0;
}

/****************************************************************************
 * Name: fe310_gpio_clearpending
 ****************************************************************************/

void fe310_gpio_clearpending(uint32_t pin)
{
  ASSERT(0 <= pin && pin <= 31);

  /* Clear all gpio interrupts for the pin */

  modifyreg32(FE310_GPIO_RISE_IP, 0x0, 0x1 << pin);
  modifyreg32(FE310_GPIO_FALL_IP, 0x0, 0x1 << pin);
  modifyreg32(FE310_GPIO_HIGH_IP, 0x0, 0x1 << pin);
  modifyreg32(FE310_GPIO_LOW_IP,  0x0, 0x1 << pin);
}