Add GPIO driver

Provide the basic functionality for setting direction, turning on and
off, toggling, reading inputs, and enabling/disabling pullups.

This chip also provides pulldowns, so in the future I will also
implement pulldown control so we can detect shorts to 5V.

hal/m258ke/gpio.c

@@ -0,0 +1,112 @@
+/*
+ * gpio.c
+ *
+ *  Created on: Jun 19, 2023
+ *      Author: Doug
+ *
+ * Copyright (C) 2011-2023 Doug Brown
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../gpio.h"
+#include "nuvoton/NuMicro.h"
+
+/// The GPIO ports available on the M258KE
+static GPIO_T * const gpioRegs[] = {
+	PA,
+	PB,
+	PC,
+	PD,
+	PE,
+	PF
+};
+
+/** Sets the direction of a GPIO pin.
+ *
+ * @param pin The pin
+ * @param output True if it should be an output, false if it should be an input
+ */
+void GPIO_SetDirection(GPIOPin pin, bool output)
+{
+	if (output)
+	{
+		uint32_t tmp = gpioRegs[pin.port]->MODE;
+		tmp &= ~(2UL << 2*pin.pin);
+		tmp |= (1UL << 2*pin.pin);
+		gpioRegs[pin.port]->MODE = tmp;
+	}
+	else
+	{
+		gpioRegs[pin.port]->MODE &= ~(3UL << 2*pin.pin);
+	}
+}
+
+/** Sets whether an input GPIO pin is pulled up
+ *
+ * @param pin The pin
+ * @param pullup True if it should be pulled up, false if not
+ */
+void GPIO_SetPullup(GPIOPin pin, bool pullup)
+{
+	if (pullup)
+	{
+		uint32_t tmp = gpioRegs[pin.port]->PUSEL;
+		tmp &= ~(2UL << 2*pin.pin);
+		tmp |= (1UL << 2*pin.pin);
+		gpioRegs[pin.port]->PUSEL = tmp;
+	}
+	else
+	{
+		gpioRegs[pin.port]->PUSEL &= ~(3UL << 2*pin.pin);
+	}
+}
+
+/** Turns a GPIO pin on (sets it high)
+ *
+ * @param pin The pin
+ */
+void GPIO_SetOn(GPIOPin pin)
+{
+	gpioRegs[pin.port]->DOUT |= (1 << pin.pin);
+}
+
+/** Turns a GPIO pin off (sets it low)
+ *
+ * @param pin The pin
+ */
+void GPIO_SetOff(GPIOPin pin)
+{
+	gpioRegs[pin.port]->DOUT &= ~(1 << pin.pin);
+}
+
+/** Toggles a GPIO pin
+ *
+ * @param pin The pin
+ */
+void GPIO_Toggle(GPIOPin pin)
+{
+	gpioRegs[pin.port]->DOUT ^= (1 << pin.pin);
+}
+
+/** Reads the input status of a GPIO pin
+ *
+ * @param pin The pin
+ * @return True if it's high, false if it's low
+ */
+bool GPIO_Read(GPIOPin pin)
+{
+	return gpioRegs[pin.port]->PIN & (1 << pin.pin);
+}

hal/m258ke/gpio_hw.h

@@ -0,0 +1,38 @@
+/*
+ * gpio_hw.h
+ *
+ *  Created on: Jun 19, 2023
+ *      Author: Doug
+ *
+ * Copyright (C) 2011-2023 Doug Brown
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef HAL_M258KE_GPIO_HW_H_
+#define HAL_M258KE_GPIO_HW_H_
+
+/// Enum representing the different GPIO ports available on the M258KE.
+/// Used with the GPIOPin struct.
+enum {
+	GPIOA,
+	GPIOB,
+	GPIOC,
+	GPIOD,
+	GPIOE,
+	GPIOF
+};
+
+#endif /* HAL_M258KE_GPIO_HW_H_ */