Properly set the mode during OpenPin()

Author: davecheney

examples/blink/blink.go

@@ -2,15 +2,17 @@ package main
 
 import (
 	"fmt"
-	"github.com/davecheney/gpio"
 	"os"
 	"os/signal"
 	"time"
+
+	"github.com/davecheney/gpio"
+	"github.com/davecheney/gpio/rpi"
 )
 
 func main() {
 	// set GPIO25 to output mode
-	pin, err := gpio.OpenPin(25, gpio.ModeOutput)
+	pin, err := gpio.OpenPin(rpi.GPIO_P1_22, gpio.ModeOutput)
 	if err != nil {
 		fmt.Printf("Error opening pin! %s\n", err)
 		return

gpio_linux.go

@@ -67,14 +67,17 @@ func OpenPin(n int, mode Mode) (Pin, error) {
 		modePath:  filepath.Join(pinBase, "direction"),
 		valueFile: value,
 	}
-	p.SetMode(mode)
+	if err := p.setMode(mode); err != nil {
+		p.Close()
+		return nil, err
+	}
 	return p, nil
 }
 
 // write opens a file for writing, writes the byte slice to it and closes the
 // file.
 func write(buf []byte, path string) error {
-	file, err := os.OpenFile(filepath.Join(gpiobase, path), os.O_WRONLY, 0600)
+	file, err := os.OpenFile(path, os.O_WRONLY, 0600)
 	if err != nil {
 		return err
 	}
@@ -103,7 +106,11 @@ func (p *pin) Mode() Mode {
 
 // SetMode sets the mode of the pin.
 func (p *pin) SetMode(mode Mode) {
-	p.err = write([]byte(mode), p.modePath)
+	p.err = p.setMode(mode)
+}
+
+func (p *pin) setMode(mode Mode) error {
+	return write([]byte(mode), p.modePath)
 }
 
 // Set sets the pin level high.

gpio_linux_test.go

@@ -36,12 +36,14 @@ func TestSetDirection(t *testing.T) {
 		t.Fatal(err)
 	}
 	defer pin.Close()
+	if dir, err := pin.Mode(), pin.Err(); dir != gpio.ModeInput || err != nil {
+		t.Fatalf("pin.Mode(): expected %v %v , got %v %v", gpio.ModeInput, nil, dir, err)
+	}
 	pin.SetMode(gpio.ModeOutput)
 	if pin.Err() != nil {
 		t.Fatal(err)
 	}
-	dir := pin.Mode()
-	if err := pin.Err(); dir != gpio.ModeOutput || err != nil {
+	if dir, err := pin.Mode(), pin.Err(); dir != gpio.ModeOutput || err != nil {
 		t.Fatalf("pin.Mode(): expected %v %v , got %v %v", gpio.ModeOutput, nil, dir, err)
 	}
 }