Implemented GPIO.

Signed-off-by: Yilin Sun <imi415@imi.moe>

README.md

@@ -0,0 +1,18 @@
+# WIP
+
+## Implemented features:
+```ruby
+# Initialization: Takes a hash with configuration.
+led_red   = Machine::GPIO.new({pin: 38, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
+led_blue  = Machine::GPIO.new({pin: 36, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
+led_green = Machine::GPIO.new({pin: 39, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
+```
+
+```ruby
+led_red.value # Get LED pin input value
+led_red.value = Machine::GPIO::OFF # Turn on the LED (Level is reversed)
+led_red.off # Same as above
+led_red.on # Turn off the LED (Level is reversed)
+led_red.toggle # Toggle output
+```
+

lib/mruby

@@ -1 +1 @@
-Subproject commit 3e175303e53c4126a94828f89d028bf57e57a889
+Subproject commit 12b520e7873432d7135f9de86330c000f8464873

src/mrb_machine_impl/mrb_machine_gpio_impl.c

@@ -5,16 +5,64 @@
 
 /* SDK drivers */
 #include "fsl_gpio.h"
+#include "fsl_iocon.h"
 
 /* Gem private */
 #include "machine-gpio/src/gpio.h"
 
+#define GPIO_IMPL_PORT(x) (x / 32)
+#define GPIO_IMPL_PIN(x)  (x % 32)
+
 int mrb_machine_gpio_impl_config(uint32_t pin, machine_gpio_config_t *cfg) {
-    printf("IO initialize: Pin %ld to %d, init %d\n", pin, cfg->mode, cfg->initial_value);
+    /**
+     * IO pin naming for LPC55S69:
+     * LPC5500 series has 2 IO ports, each with 32 pins, named PIO[0-1][0-31]
+     * Port 1 starts at 32, e.g. pin 32: PIO[1][0], pin 33: PIO[1][1]
+     */
+
+    uint32_t iocon_mode = IOCON_PIO_FUNC(0) | IOCON_PIO_SLEW(0) | IOCON_DIGITAL_EN;
+
+    gpio_pin_direction_t dir      = (cfg->mode == MACHINE_GPIO_MODE_INPUT) ? kGPIO_DigitalInput : kGPIO_DigitalOutput;
+    uint8_t              init_val = (cfg->initial_value == MACHINE_GPIO_HIGH) ? 1 : 0;
+
+    if (cfg->pull == MACHINE_GPIO_PULL_UP) {
+        iocon_mode |= IOCON_PIO_MODE(2); /* Pull-up */
+    } else if (cfg->pull == MACHINE_GPIO_PULL_DOWN) {
+        iocon_mode |= IOCON_PIO_MODE(1); /* Pull-down */
+    }
+
+    if (cfg->mode == MACHINE_GPIO_MODE_OUTPUT_OPENDRAIN) {
+        iocon_mode |= IOCON_OPENDRAIN_EN;
+    }
+
+    IOCON_PinMuxSet(IOCON, GPIO_IMPL_PORT(pin), GPIO_IMPL_PIN(pin), iocon_mode);
+
+    gpio_pin_config_t pin_cfg = {
+        .pinDirection = dir,
+        .outputLogic  = init_val,
+    };
+
+    GPIO_PinInit(GPIO, GPIO_IMPL_PORT(pin), GPIO_IMPL_PIN(pin), &pin_cfg);
 
     return 0;
 }
 
-int mrb_machine_gpio_read(uint32_t pin) {
+int mrb_machine_gpio_impl_read(uint32_t pin) {
+    if (GPIO_PinRead(GPIO, GPIO_IMPL_PORT(pin), GPIO_IMPL_PIN(pin))) {
+        return 1;
+    }
+
     return 0;
-}
+}
+
+int mrb_machine_gpio_impl_write(uint32_t pin, machine_gpio_value_t val) {
+    uint8_t pin_val = (val == MACHINE_GPIO_HIGH) ? 1 : 0;
+
+    GPIO_PinWrite(GPIO, GPIO_IMPL_PORT(pin), GPIO_IMPL_PIN(pin), pin_val);
+    return 0;
+}
+
+int mrb_machine_gpio_impl_toggle(uint32_t pin) {
+    GPIO_PortToggle(GPIO, GPIO_IMPL_PORT(pin), (1 << GPIO_IMPL_PIN(pin)));
+    return 0;
+}