Commit 12/08/2025

src/sbc/DigitalOutput.kt

@@ -0,0 +1,157 @@
+package sbc
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import org.slf4j.LoggerFactory
+import somecodes.Codes.Companion.gpioExportPath
+import somecodes.Codes.Companion.gpioPath
+import somecodes.Codes.Companion.gpioUnexportPath
+import somecodes.Codes.Companion.haveGpioSupport
+import java.nio.file.Files
+import java.nio.file.Path
+import kotlin.io.path.isDirectory
+
+/**
+ * Create a digital output for a GPIO pin.
+ * @param linuxGpio The GPIO pin number in Linux.
+ * @param name The name of the digital output.
+ * @param activeHigh If true, the output is active high (default is true).
+ * @property inited Indicates whether the digital output has been initialized.
+ *
+ */
+@Suppress("unused")
+class DigitalOutput(val linuxGpio: Int, val name: String, val activeHigh: Boolean = true) {
+    var inited = false; private set
+    private var valuepath: Path? = null
+    private val logger = LoggerFactory.getLogger("DigitalOutput $name ($linuxGpio)")
+    init{
+        if (haveGpioSupport()){
+            if (checkExists()){
+                // already exists
+                try{
+                    // try to set direction to output
+                    val dir = gpioPath.resolve("gpio$linuxGpio").resolve("direction")
+                    Files.writeString(dir, "out")
+                    // successfully set direction to output
+                    inited = true
+                    valuepath = gpioPath.resolve("gpio$linuxGpio").resolve("value")
+                    logger.info("GPIO $name GPIO $linuxGpio already exists as output")
+                } catch (e : Exception){
+                    // failed to set direction to output, log error
+                    logger.error("Failed to set existing GPIO $name GPIO $linuxGpio as output: ${e.message}")
+                }
+
+            } else {
+                // not yet exists, export it
+                try{
+                    // export the GPIO pin
+                    Files.writeString(gpioExportPath, linuxGpio.toString())
+                    if (checkExists()){
+                        // successfully exported, now set direction to output
+                        val dir = gpioPath.resolve("gpio$linuxGpio").resolve("direction")
+                        Files.writeString(dir, "out")
+                        inited = true
+                        valuepath = gpioPath.resolve("gpio$linuxGpio").resolve("value")
+                        logger.info("Initialized GPIO $name GPIO $linuxGpio as output")
+                    } else {
+                        // failed to export, log error
+                        logger.error("GPIO $name GPIO $linuxGpio does not exist after export")
+                    }
+
+
+                } catch (e: Exception){
+                // failed to export GPIO pin, log error
+                    logger.error("Failed to export GPIO $name GPIO $linuxGpio: ${e.message}")
+                }
+            }
+
+
+        } else logger.error("DigitalOutput $name GPIO $linuxGpio not initialized: GPIO support not available")
+    }
+
+    fun checkExists(): Boolean{
+        return try {
+            val gpioPath = gpioPath.resolve("gpio$linuxGpio")
+            if (gpioPath.isDirectory() && gpioPath.toFile().exists()){
+                val dir = gpioPath.resolve("direction").toFile()
+                val value = gpioPath.resolve("value").toFile()
+                if (dir.exists() && value.exists()) {
+                    return dir.canWrite() && value.canWrite()
+                }
+            }
+            false
+        } catch (e: Exception) {
+            logger.error("Error checking if GPIO $linuxGpio exists: ${e.message}")
+            false
+        }
+    }
+
+    /**
+     * Release the GPIO pin by unexporting it.
+     */
+    fun release(){
+        if (inited){
+            try{
+                Files.writeString(gpioUnexportPath, linuxGpio.toString())
+                inited = false
+                valuepath = null
+            } catch (e : Exception){
+                logger.error("Failed to unexport GPIO $name GPIO ${e.message}")
+            }
+        }
+    }
+
+    /**
+     * Set Digital Output to ON
+     */
+    fun setON() : Boolean{
+        if (inited){
+            if (valuepath!=null){
+                try{
+                    Files.writeString(valuepath!!, if (activeHigh) "1" else "0")
+                    return true
+                } catch (e: Exception){
+                    logger.error("Failed to set GPIO $name GPIO $linuxGpio ON: ${e.message}")
+                }
+            }
+
+        }
+        return false
+    }
+
+    /**
+     * Set Digital Output to OFF
+     */
+    fun setOFF() : Boolean{
+        if (inited){
+            if (valuepath!=null){
+                try{
+                    Files.writeString(valuepath!!, if (activeHigh) "0" else "1")
+                    return true
+                } catch (e : Exception){
+                    logger.error("Failed to set GPIO $name GPIO $linuxGpio OFF: ${e.message}")
+                }
+            }
+        }
+        return false
+    }
+
+    /**
+     * Blink the Digital Output for a specified duration.
+     * @param ms The duration in milliseconds to keep the output ON before turning it OFF (default is 50ms).
+     */
+    fun Blink(ms: Long = 50){
+        if (inited){
+            CoroutineScope(Dispatchers.IO).launch {
+                setON()
+                delay(ms)
+                setOFF()
+            }
+        }
+    }
+
+
+
+}