From 3a4663150e9dd1792ca8a91fa4e76c4549ab4210 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Fri, 27 Apr 2018 01:29:13 +0200
Subject: [PATCH] runtime: Implement GPIO output

Now we can actually blink a LED!
---
 src/examples/blinky/blinky.go | 15 +++++++++++----
 src/machine/machine.go        | 26 ++++++++++++++++++++++++++
 src/runtime/nrfx_config.h     |  4 ++++
 src/runtime/runtime_nrf.c     | 16 ++++++++++++++++
 src/runtime/runtime_nrf.h     |  9 +++++++++
 5 files changed, 66 insertions(+), 4 deletions(-)
 create mode 100644 src/machine/machine.go

diff --git a/src/examples/blinky/blinky.go b/src/examples/blinky/blinky.go
index efda2708..10aaeb79 100644
--- a/src/examples/blinky/blinky.go
+++ b/src/examples/blinky/blinky.go
@@ -1,14 +1,21 @@
 
 package main
 
-import "runtime"
+import (
+	"machine"
+	"runtime"
+)
 
 func main() {
+	led := machine.GPIO{17} // LED 1 on the PCA10040
+	led.Configure(machine.GPIOConfig{Mode: machine.GPIO_OUTPUT})
 	for {
-		// TODO: enable/disable actual LED
 		println("LED on")
-		runtime.Sleep(runtime.Millisecond * 250)
+		led.Set(false)
+		runtime.Sleep(runtime.Millisecond * 500)
+
 		println("LED off")
-		runtime.Sleep(runtime.Millisecond * 250)
+		led.Set(true)
+		runtime.Sleep(runtime.Millisecond * 500)
 	}
 }
diff --git a/src/machine/machine.go b/src/machine/machine.go
new file mode 100644
index 00000000..952addf5
--- /dev/null
+++ b/src/machine/machine.go
@@ -0,0 +1,26 @@
+
+package machine
+
+// #include "../runtime/runtime_nrf.h"
+import "C"
+
+type GPIO struct {
+	Pin uint32
+}
+
+type GPIOConfig struct {
+	Mode uint8
+}
+
+const (
+	GPIO_INPUT  = iota
+	GPIO_OUTPUT
+)
+
+func (p GPIO) Configure(config GPIOConfig) {
+	C.gpio_cfg(C.uint(p.Pin), C.gpio_mode_t(config.Mode))
+}
+
+func (p GPIO) Set(value bool) {
+	C.gpio_set(C.uint(p.Pin), C.bool(value))
+}
diff --git a/src/runtime/nrfx_config.h b/src/runtime/nrfx_config.h
index e69de29b..f2086eb4 100644
--- a/src/runtime/nrfx_config.h
+++ b/src/runtime/nrfx_config.h
@@ -0,0 +1,4 @@
+
+#pragma once
+
+#define NRFX_ASSERT(expression) do { bool res = expression; (void)res; } while (0)
diff --git a/src/runtime/runtime_nrf.c b/src/runtime/runtime_nrf.c
index b0be67b5..b60e43ae 100644
--- a/src/runtime/runtime_nrf.c
+++ b/src/runtime/runtime_nrf.c
@@ -1,7 +1,9 @@
 
+#include "hal/nrf_gpio.h"
 #include "hal/nrf_uart.h"
 #include "nrf.h"
 #include "runtime.h"
+#include "runtime_nrf.h"
 #include <string.h>
 
 void uart_init(uint32_t pin_tx) {
@@ -46,6 +48,20 @@ void RTC0_IRQHandler() {
 	rtc_wakeup = true;
 }
 
+void gpio_cfg(uint32_t pin, gpio_mode_t mode) {
+	nrf_gpio_cfg(
+			pin,
+			mode == GPIO_INPUT ? NRF_GPIO_PIN_DIR_INPUT : NRF_GPIO_PIN_DIR_OUTPUT,
+			mode == GPIO_INPUT ? NRF_GPIO_PIN_INPUT_CONNECT : NRF_GPIO_PIN_INPUT_DISCONNECT,
+			NRF_GPIO_PIN_NOPULL,
+			NRF_GPIO_PIN_S0S1,
+			NRF_GPIO_PIN_NOSENSE);
+}
+
+void gpio_set(uint32_t pin, bool high) {
+	nrf_gpio_pin_write(pin, high);
+}
+
 void _start() {
 	main();
 }
diff --git a/src/runtime/runtime_nrf.h b/src/runtime/runtime_nrf.h
index 61acc3f5..945518f5 100644
--- a/src/runtime/runtime_nrf.h
+++ b/src/runtime/runtime_nrf.h
@@ -2,9 +2,18 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdbool.h>
 
 void uart_init(uint32_t pin_tx);
 void uart_send(uint8_t c);
 
 void rtc_init();
 void rtc_sleep(uint32_t ticks);
+
+typedef enum {
+	GPIO_INPUT,
+	GPIO_OUTPUT,
+} gpio_mode_t;
+
+void gpio_cfg(uint32_t pin, gpio_mode_t mode);
+void gpio_set(uint32_t pin, bool high);