gpio.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2019 Tobias Hienzsch
 
#ifndef TETL_HARDWARE_STM32_GPIO_HPP
#define TETL_HARDWARE_STM32_GPIO_HPP
 
#include <etl/version.hpp>
 
#include <etl/cstdint.hpp>
#include <etl/new.hpp>
#include <etl/utility.hpp>
 
namespace etl::experimental::hardware::stm32 {
enum struct pin_number : etl::uint16_t {
    pin_0 = 0,
    pin_1,
    pin_2,
    pin_3,
    pin_4,
    pin_5,
    pin_6,
    pin_7,
    pin_8,
    pin_9,
    pin_10,
    pin_11,
    pin_12,
    pin_13,
    pin_14,
    pin_15,
};
 
enum struct pin_state : etl::uint8_t {
    reset = 0,
    set,
};
 
inline auto val(pin_number pin) -> etl::uint16_t
{
    return static_cast<etl::uint16_t>(pin);
}
 
struct gpio_memory_layout {
    etl::uint32_t volatile control_low;
    etl::uint32_t volatile control_high;
    etl::uint32_t volatile input_data;
    etl::uint32_t volatile output_data;
    etl::uint32_t volatile bit_set_reset;
    etl::uint32_t volatile bit_set;
    etl::uint32_t volatile lock;
};
 
struct port {
    ~port() = default;
 
    port(port const&)                    = delete;
    auto operator=(port const&) -> port& = delete;
 
    port(port&&)                    = delete;
    auto operator=(port&&) -> port& = delete;
 
    auto toggle_pin(pin_number pin) noexcept -> void;
    auto write(pin_number pin, pin_state state) noexcept -> void;
    [[nodiscard]] auto read(pin_number pin) noexcept -> pin_state;
 
    [[nodiscard]] static auto place_at(void* addr) -> port&;
 
private:
    explicit port() = default;
 
    gpio_memory_layout _memory;
};
 
inline auto port::read(pin_number const pin) noexcept -> pin_state
{
    etl::ignore_unused(this, pin);
    return {};
}
 
inline auto port::write(pin_number const pin, pin_state const state) noexcept -> void
{
    if (state == pin_state::reset) {
        _memory.bit_set_reset = (1U << val(pin));
        return;
    }
    _memory.bit_set_reset = (1U << (val(pin) + 16U));
}
 
inline auto port::toggle_pin(pin_number const pin) noexcept -> void
{
    _memory.output_data = _memory.output_data ^ (1U << val(pin));
}
 
inline auto port::place_at(void* addr) -> port&
{
    return *new (addr) port;
}
 
} // namespace etl::experimental::hardware::stm32
 
#endif // TETL_HARDWARE_STM32_GPIO_HPP