From 01bae1264436a5e810d3cfe734dc07256275dc56 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jeremy@system76.com>
Date: Sun, 29 Sep 2019 21:47:37 -0600
Subject: [PATCH] Add AVR GPIO

---
 src/arch/avr/gpio.c              | 33 ++++++++++++++++++++++++++++++++
 src/arch/avr/include/arch/gpio.h | 27 ++++++++++++++++++++++++++
 src/board/arduino/uno/main.c     |  5 +++++
 3 files changed, 65 insertions(+)
 create mode 100644 src/arch/avr/gpio.c
 create mode 100644 src/arch/avr/include/arch/gpio.h

diff --git a/src/arch/avr/gpio.c b/src/arch/avr/gpio.c
new file mode 100644
index 0000000..95e036d
--- /dev/null
+++ b/src/arch/avr/gpio.c
@@ -0,0 +1,33 @@
+#include <arch/gpio.h>
+
+bool gpio_get_dir(struct Gpio * gpio) {
+    if (*gpio->ddr & gpio->value) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void gpio_set_dir(struct Gpio * gpio, bool value) {
+    if (value) {
+        *gpio->ddr |= gpio->value;
+    } else {
+        *gpio->ddr &= ~gpio->value;
+    }
+}
+
+bool gpio_get(struct Gpio * gpio) {
+    if (*gpio->pin & gpio->value) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void gpio_set(struct Gpio * gpio, bool value) {
+    if (value) {
+        *gpio->port |= gpio->value;
+    } else {
+        *gpio->port &= ~gpio->value;
+    }
+}
diff --git a/src/arch/avr/include/arch/gpio.h b/src/arch/avr/include/arch/gpio.h
new file mode 100644
index 0000000..f7484f1
--- /dev/null
+++ b/src/arch/avr/include/arch/gpio.h
@@ -0,0 +1,27 @@
+#ifndef _ARCH_GPIO_H
+#define _ARCH_GPIO_H
+
+#include <avr/io.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+struct Gpio {
+    volatile uint8_t * pin;
+    volatile uint8_t * ddr;
+    volatile uint8_t * port;
+    uint8_t value;
+};
+
+#define GPIO(BLOCK, NUMBER) { \
+    .pin = &PIN ## BLOCK, \
+    .ddr = &DDR ## BLOCK, \
+    .port = &PORT ## BLOCK, \
+    .value = (1 << NUMBER), \
+}
+
+bool gpio_get(struct Gpio * gpio);
+void gpio_set(struct Gpio * gpio, bool value);
+bool gpio_get_dir(struct Gpio * gpio);
+void gpio_set_dir(struct Gpio * gpio, bool value);
+
+#endif // _ARCH_GPIO_H
diff --git a/src/board/arduino/uno/main.c b/src/board/arduino/uno/main.c
index 0bb752b..434b81d 100644
--- a/src/board/arduino/uno/main.c
+++ b/src/board/arduino/uno/main.c
@@ -1,14 +1,19 @@
 #include <stdio.h>
 
+#include <arch/gpio.h>
 #include <arch/uart.h>
 
 void init(void) {
     uart_stdio_init(0, 9600);
 }
 
+struct Gpio LED = GPIO(B, 5);
+
 int main(void) {
     init();
 
+    gpio_set_dir(&LED, true);
+    gpio_set(&LED, false);
     printf("Hello from System76 EC for the Arduino Uno!\n");
     for (;;) {
         int c = getchar();