Add: power on with context, SIM808 support

api/modem/gpio/gpio.go

@@ -1,6 +1,7 @@
 package gpio
 
 import (
+	"context"
 	"io"
 	"log"
 	"time"
@@ -8,6 +9,10 @@ import (
 	gpio "github.com/stianeikeland/go-rpio/v4"
 )
 
+const (
+	waitCtxTimeout = 100 * time.Microsecond
+)
+
 type gpioPin struct {
 	logger *log.Logger
 	pin    gpio.Pin
@@ -16,7 +21,7 @@ type gpioPin struct {
 type Pin interface {
 	Init() error
 	PowerOn()
-	PowerOff()
+	PowerOnCtx(ctx context.Context)
 	io.Closer
 }
 
@@ -31,32 +36,47 @@ func (p gpioPin) Init() error {
 	return gpio.Open()
 }
 
-func (p gpioPin) sendOnOffSignal() {
+func waitCtx(ctx context.Context, timeout time.Duration) {
+	deadline := time.Now().Add(timeout)
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+			if time.Now().After(deadline) {
+				return
+			}
+		}
+		time.Sleep(waitCtxTimeout)
+	}
+}
+
+func (p gpioPin) sendOnOffSignal(ctx context.Context) {
 	p.pin.Output()
 	p.logger.Println("Power on 0/3 + 100ms")
 	p.pin.Low()
 	p.pin.Toggle()
-	time.Sleep(100 * time.Millisecond)
+	waitCtx(ctx, 100*time.Millisecond)
 
 	p.logger.Println("Power on 1/3 + 3s")
 	p.pin.High()
 	p.pin.Toggle()
-	time.Sleep(3 * time.Second)
+	waitCtx(ctx, 3*time.Second)
 
 	p.logger.Println("Power on 2/3 + 30s")
 	p.pin.Low()
 	p.pin.Toggle()
-	time.Sleep(30 * time.Second)
+	waitCtx(ctx, 30*time.Second)
 
 	p.logger.Println("Power on 3/3")
 }
 
 func (p gpioPin) PowerOn() {
-	p.sendOnOffSignal()
+	p.sendOnOffSignal(context.Background())
 }
 
-func (p gpioPin) PowerOff() {
-	p.sendOnOffSignal()
+func (p gpioPin) PowerOnCtx(ctx context.Context) {
+	p.sendOnOffSignal(ctx)
 }
 
 func (p gpioPin) Close() error {