[stm32] Add type-erased Gpio wrapper

Author: chris-durand

src/modm/platform/gpio/stm32/gpio_accessor.hpp.in

@@ -0,0 +1,119 @@
+/*
+* Copyright (c) 2021, Christopher Durand
+*
+* This file is part of the modm project.
+*
+* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/.
+*/
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_STM32_GPIO_ACCESSOR_HPP
+#define MODM_STM32_GPIO_ACCESSOR_HPP
+
+#include <array>
+
+#include "../device.hpp"
+#include "base.hpp"
+
+namespace modm::platform
+{
+
+/**
+* Type-erased Gpio wrapper
+*
+* Example:
+* @code
+*  GpioAccessor gpio = GpioAccessor::template fromGpio<GpioA1>();
+*  gpio.toggle();
+* @endcode
+*
+* @author	Christopher Durand
+* @ingroup	modm_platform_gpio
+*/
+class GpioAccessor : public Gpio
+{
+private:
+	// Store port as uintptr_t instead of GPIO_TypeDef*
+	// because ST's GPIOx macros have an int-to-pointer cast
+	// not possible during compile-time evaluation
+	uintptr_t portAddress;
+	uint16_t idBit;
+
+	static consteval uintptr_t
+	getPort(Port id)
+	{
+		switch (id)
+		{
+%% for port in ports
+		case Port::{{ port | upper }}:
+			return GPIO{{ port | upper }}_BASE;
+%% endfor
+		}
+	}
+
+	auto port() const { return reinterpret_cast<GPIO_TypeDef *>(portAddress); }
+
+	constexpr GpioAccessor(uintptr_t port, uint8_t position)
+		: portAddress{port}, idBit{uint16_t(1u << position)}
+	{}
+
+public:
+	using PortType = GPIO_TypeDef *;
+
+	GpioAccessor(PortType port, uint8_t position)
+		: portAddress{reinterpret_cast<uintptr_t>(port)}, idBit{uint16_t(1u << position)}
+	{}
+
+	template<class Gpio>
+	static constexpr GpioAccessor fromGpio()
+	{
+		static_assert(!Gpio::isInverted, "Inverted Gpios are not supported");
+		return GpioAccessor{getPort(Gpio::port), Gpio::pin};
+	}
+
+	void set() const
+	{
+		port()->BSRR = idBit;
+	}
+
+	void reset() const
+	{
+		port()->BSRR = (idBit << 16);
+	}
+
+	void set(bool enable) const
+	{
+		if(enable) {
+			set();
+		} else {
+			reset();
+		}
+	}
+
+	bool isSet() const
+	{
+		return (port()->ODR & idBit);
+	}
+
+	void toggle() const
+	{
+		set(!isSet());
+	}
+
+	bool read() const
+	{
+		return (port()->IDR & idBit);
+	}
+};
+
+template<typename... Gpios>
+constexpr auto makeGpioArray()
+{
+	return std::array{ GpioAccessor::template fromGpio<Gpios>()... };
+}
+
+}
+
+#endif // MODM_STM32_GPIO_ACCESSOR_HPP

src/modm/platform/gpio/stm32/module.lb

@@ -303,6 +303,7 @@ def build(env):
     env.template("unused.hpp.in")
     if len(env["enable_ports"]):
         env.template("enable.cpp.in")
+    env.template("gpio_accessor.hpp.in")
 
     env.copy("../common/inverted.hpp", "inverted.hpp")
     env.copy("../common/connector.hpp", "connector.hpp")