/*
 * Copyright (C) 2020 Koen Zandberg <koen@bergzand.net>
 *
 * This file is subject to the terms and conditions of the GNU Lesser General
 * Public License v2.1. See the file LICENSE in the top level directory for more
 * details.
 */
/**
 * @ingroup         cpu_gd32v
 * @{
 *
 * @file
 * @brief           GD32V GPIO implementation
 *
 * @author          Koen Zandberg <koen@bergzand.net>
 */

#include "cpu.h"
#include "clic.h"
#include "periph_cpu.h"
#include "periph/gpio.h"

/**
 * @brief   Extract information from mode parameter
 */
#define MODE_MASK                       (0x0f)
#define ODR_POS                         (4U)

/**
 * @brief   Extract the port base address from the given pin identifier
 */
static inline GPIO_Type *_port(gpio_t pin)
{
    return (GPIO_Type *)(pin & ~(0x0f));
}

/**
 * @brief   Extract the port number form the given identifier
 *
 * The port number is extracted by looking at bits 10, 11, 12, 13 of the base
 * register addresses.
 */
static inline int _port_num(gpio_t pin)
{
    return (((pin >> 10) & 0x0f) - 2);
}

/**
 * @brief   Extract the pin number from the last 4 bit of the pin identifier
 */
static inline int _pin_num(gpio_t pin)
{
    return (pin & 0x0f);
}

static inline void _port_enable_clock(gpio_t pin)
{
    periph_clk_en(APB2, (RCU_APB2EN_PAEN_Msk << _port_num(pin)));
}

/**
 * @brief   Check if the given mode is some kind of input mode
 * @param[in]   mode    Mode to check
 * @retval  1           @p mode is GPIO_IN, GPIO_IN_PD, or GPIO_IN_PU
 * @retval  0           @p mode is not an input mode
 */
static inline int gpio_mode_is_input(gpio_mode_t mode)
{
    return !(mode & 3);
}

static inline void _set_mode_or_af(GPIO_Type *port, unsigned pin_num,
                                   unsigned mode_or_af)
{
    volatile uint32_t *crl = (&port->CTL0 + (pin_num >> 3));
    uint32_t tmp = *crl;

    tmp &= ~(0xf << ((pin_num & 0x7) * 4));
    tmp |= ((mode_or_af & MODE_MASK) << ((pin_num & 0x7) * 4));
    *crl = tmp;
}

static inline bool _pin_is_output(GPIO_Type *port, unsigned pin_num)
{
    uint32_t reg = *(uint32_t *)(&port->CTL0 + (pin_num >> 3));

    return reg & (0x3 << ((pin_num & 0x7) << 2));
}

int gpio_init(gpio_t pin, gpio_mode_t mode)
{
    GPIO_Type *port = _port(pin);
    unsigned pin_num = _pin_num(pin);

    /* open-drain output with pull-up is not supported */
    if (mode == GPIO_OD_PU) {
        return -1;
    }

    /* enable the clock for the selected port */
    _port_enable_clock(pin);

    /* set pin mode */
    _set_mode_or_af(port, pin_num, mode);

    /* For input modes, ODR controls pull up settings */
    if (gpio_mode_is_input(mode)) {
        if (mode == GPIO_IN_PU) {
            cpu_reg_enable_bits(&port->OCTL, 1 << pin_num);
        }
        else {
            cpu_reg_disable_bits(&port->OCTL, 1 << pin_num);
        }
    }

    return 0; /* all OK */
}

void gpio_init_af(gpio_t pin, gpio_af_t af)
{
    GPIO_Type *port = _port(pin);
    unsigned pin_num = _pin_num(pin);

    /* enable the clock for the selected port */
    _port_enable_clock(pin);
    /* configure the pin */
    _set_mode_or_af(port, pin_num, af);
}

void gpio_init_analog(gpio_t pin)
{
    /* enable the GPIO port RCC */
    _port_enable_clock(pin);

    /* map the pin as analog input */
    int pin_num = _pin_num(pin);

    volatile uint32_t *pin_reg = (uint32_t *)(&_port(pin)->CTL0 + (pin_num >= 8));
    *pin_reg &= ~(0xfl << (4 * (pin_num - ((pin_num >= 8) * 8))));
}

int gpio_read(gpio_t pin)
{
    GPIO_Type *port = _port(pin);
    unsigned pin_num = _pin_num(pin);

    if (_pin_is_output(port, pin)) {
        /* pin is output */
        return (port->OCTL & (1 << pin_num));
    }
    else {
        /* or input */
        return (port->ISTAT & (1 << pin_num));
    }
}

void gpio_set(gpio_t pin)
{
    _port(pin)->BOP = (1 << _pin_num(pin));
}

void gpio_clear(gpio_t pin)
{
    _port(pin)->BC = (1 << _pin_num(pin));
}

void gpio_toggle(gpio_t pin)
{
    if (gpio_read(pin)) {
        gpio_clear(pin);
    }
    else {
        gpio_set(pin);
    }
}

void gpio_write(gpio_t pin, int value)
{
    if (value) {
        gpio_set(pin);
    }
    else {
        gpio_clear(pin);
    }
}

/** @} */