update BRC pulse handling

pi/roverd/brc.go

@@ -2,36 +2,42 @@ package roverd
 
 import (
 	"context"
-	"fmt"
 	"log"
-	"os"
-	"path/filepath"
-	"strconv"
 	"time"
+
+	gpiocdev "github.com/warthog618/go-gpiocdev"
 )
 
 type BRCPulser struct {
 	cfg    BRCConfig
 	logger *log.Logger
+	line   *gpiocdev.Line
 }
 
 func NewBRCPulser(cfg BRCConfig, logger *log.Logger) (*BRCPulser, error) {
-	if err := exportGPIO(cfg.GPIOPin); err != nil {
-		return nil, err
+	chip := cfg.GPIOChip
+	if chip == "" {
+		chip = "gpiochip0"
 	}
-	if err := writeGPIO(cfg.GPIOPin, "direction", []byte("out\n")); err != nil {
-		return nil, err
-	}
-	if err := writeGPIO(cfg.GPIOPin, "value", []byte("1\n")); err != nil {
+
+	line, err := gpiocdev.RequestLine(
+		chip,
+		cfg.GPIOPin,
+		gpiocdev.AsOutput(1),
+		gpiocdev.WithConsumer("roverd-brc"),
+	)
+	if err != nil {
 		return nil, err
 	}
 
-	return &BRCPulser{cfg: cfg, logger: logger}, nil
+	return &BRCPulser{cfg: cfg, logger: logger, line: line}, nil
 }
 
 func (b *BRCPulser) Close() {
-	_ = writeGPIO(b.cfg.GPIOPin, "value", []byte("1\n"))
-	_ = unexportGPIO(b.cfg.GPIOPin)
+	if b.line != nil {
+		_ = b.line.SetValue(1)
+		b.line.Close()
+	}
 }
 
 func (b *BRCPulser) Start(ctx context.Context) {
@@ -51,33 +57,15 @@ func (b *BRCPulser) Start(ctx context.Context) {
 }
 
 func (b *BRCPulser) pulseOnce() {
-	if err := writeGPIO(b.cfg.GPIOPin, "value", []byte("0\n")); err != nil {
+	if b.line == nil {
+		return
+	}
+	if err := b.line.SetValue(0); err != nil {
 		b.logger.Printf("brc pulse low: %v", err)
 		return
 	}
 	time.Sleep(b.cfg.PulseWidth.Duration)
-	if err := writeGPIO(b.cfg.GPIOPin, "value", []byte("1\n")); err != nil {
+	if err := b.line.SetValue(1); err != nil {
 		b.logger.Printf("brc pulse high: %v", err)
 	}
 }
-
-func exportGPIO(pin int) error {
-	err := os.WriteFile("/sys/class/gpio/export", []byte(strconv.Itoa(pin)), 0o644)
-	if err != nil && !os.IsExist(err) {
-		return err
-	}
-	return nil
-}
-
-func unexportGPIO(pin int) error {
-	err := os.WriteFile("/sys/class/gpio/unexport", []byte(strconv.Itoa(pin)), 0o644)
-	if err != nil && !os.IsNotExist(err) {
-		return err
-	}
-	return nil
-}
-
-func writeGPIO(pin int, field string, data []byte) error {
-	path := filepath.Join("/sys/class/gpio", fmt.Sprintf("gpio%d", pin), field)
-	return os.WriteFile(path, data, 0o644)
-}