From 68b34b8f4fe7aaf7c8bb140ba474d6eb0df413b2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micka=C3=ABl=20GALLARD?= <mlgd17@gmail.com>
Date: Sat, 6 Aug 2016 19:11:26 +0200
Subject: [PATCH 1/2] Use constant paths

---
 gpio_linux.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gpio_linux.go b/gpio_linux.go
index 7b4dac8..b2277dc 100644
--- a/gpio_linux.go
+++ b/gpio_linux.go
@@ -149,7 +149,7 @@ func read(path string) ([]byte, error) {
 
 // Close destroys the virtual files on the filesystem, unexporting the pin.
 func (p *pin) Close() error {
-	return writeFile(filepath.Join(gpiobase, "unexport"), "%d", p.number)
+	return writeFile(unexportPath, "%d", p.number)
 }
 
 // Mode retrieves the current mode of the pin.
@@ -260,7 +260,7 @@ func expose(pin int) (string, error) {
 	pinBase := filepath.Join(gpiobase, fmt.Sprintf("gpio%d", pin))
 	var err error
 	if _, statErr := os.Stat(pinBase); os.IsNotExist(statErr) {
-		err = writeFile(filepath.Join(gpiobase, "export"), "%d", pin)
+		err = writeFile(exportPath, "%d", pin)
 	}
 	return pinBase, err
 }

From fba7efaa348f6532db32fbc45e0d3e54424406eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micka=C3=ABl=20GALLARD?= <mlgd17@gmail.com>
Date: Sat, 6 Aug 2016 19:22:10 +0200
Subject: [PATCH 2/2] Patch for initial direction bug (in/out)

---
 gpio_linux.go | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/gpio_linux.go b/gpio_linux.go
index b2277dc..4c70cfc 100644
--- a/gpio_linux.go
+++ b/gpio_linux.go
@@ -98,6 +98,7 @@ type pin struct {
 	modePath      string   // the path to the /direction FD to avoid string joining each time
 	edgePath      string   // the path to the /edge FD to avoid string joining each time
 	valueFile     *os.File // the file handle for the value file
+	currentMode   Mode     // the currentMode (in/out) / empty at start time
 	callback      IRQEvent // the callback function to call when an interrupt occurs
 	initial       bool     // is this the initial epoll trigger?
 	err           error    //the last error
@@ -107,7 +108,7 @@ type pin struct {
 // It also sets the mode for the pin, making it ready for use.
 func OpenPin(n int, mode Mode) (Pin, error) {
 	// export this pin to create the virtual files on the system
-	pinBase, err := expose(n)
+	pinBase, exposed, err := expose(n)
 	if err != nil {
 		return nil, err
 	}
@@ -122,6 +123,9 @@ func OpenPin(n int, mode Mode) (Pin, error) {
 		valueFile: value,
 		initial:   true,
 	}
+	if exposed {
+		p.currentMode = p.GetMode()
+	}
 	if err := p.setMode(mode); err != nil {
 		p.Close()
 		return nil, err
@@ -171,7 +175,8 @@ func (p *pin) GetMode() Mode {
 }
 
 func (p *pin) setMode(mode Mode) error {
-	if p.GetMode() != mode {
+	if p.currentMode != mode {
+		p.currentMode = mode
 		return write([]byte(mode), p.modePath)
 	} else {
 		return nil
@@ -256,13 +261,16 @@ func (p *pin) Err() error {
 	return p.err
 }
 
-func expose(pin int) (string, error) {
+func expose(pin int) (string, bool, error) {
+	exposed := false
 	pinBase := filepath.Join(gpiobase, fmt.Sprintf("gpio%d", pin))
 	var err error
 	if _, statErr := os.Stat(pinBase); os.IsNotExist(statErr) {
 		err = writeFile(exportPath, "%d", pin)
+	} else {
+		exposed = true
 	}
-	return pinBase, err
+	return pinBase, exposed, err
 }
 
 func writeFile(path string, format string, args ...interface{}) error {