linuxfs used for SPI operations. .. Most this code base is from mpil…

pi4j-core/src/main/java/com/pi4j/io/spi/Spi.java

@@ -48,7 +48,10 @@ public interface Spi extends IO<Spi, SpiConfig, SpiProvider>, AutoCloseable, IOD
     SpiChipSelect DEFAULT_CHIP_SELECT = SpiChipSelect.CS_0;
     /** Constant <code>DEFAULT_BAUD=1000000</code> */
     int DEFAULT_BAUD = 1000000; // 1MHz (range is 500kHz - 32MHz)
-
+    /** Constant <code>DEFAULT_WRITE_LSB_FIRST</code> */
+    int DEFAULT_WRITE_LSB_FIRST = 0;
+    /** Constant <code>DEFAULT_READ_LSB_FIRST</code> */
+    int DEFAULT_READ_LSB_FIRST = 0;
     /**
      * <p>newConfigBuilder.</p>
      *

pi4j-core/src/main/java/com/pi4j/io/spi/SpiConfig.java

@@ -44,6 +44,12 @@ public interface SpiConfig extends AddressConfig<SpiConfig>, IOConfig<SpiConfig>
     String MODE_KEY = "mode";
     /** Constant <code>FLAGS_KEY="flags"</code> */
     String FLAGS_KEY = "flags";
+    /** Constant <code>WRITE_LSB_KEY="baud"</code> */
+    String WRITE_LSB_KEY = "write_lsb";
+    /** Constant <code>READ_LSB_KEY="baud"</code> */
+    String READ_LSB_KEY = "read_lsb";
+
+
 
     /**
      * <p>newBuilder.</p>
@@ -68,6 +74,42 @@ static SpiConfigBuilder newBuilder(Context context)  {
      */
     default Integer getBaud() { return baud(); }
 
+    /**
+     * <p>ReadLsbFirst.</p>
+     * In accordance with the flags parm, Read operations
+     * 0 is  LSB bit shifted first, 1 MSB bit shifted first
+     *
+     * @return a {@link java.lang.Integer} object.
+     */
+    Integer readLsbFirst();
+
+    /**
+     * <p>getreadLsbfISRT.</p>
+     *
+     * @return a {@link java.lang.Integer} object.
+     */
+    default Integer getReadLsbFirst() { return readLsbFirst(); }
+
+
+
+    /**
+     * <p>WriteLsbFirst.</p>
+     * In accordance with the flags parm, Write operations
+     * 0 is  LSB bit shifted first, 1 MSB bit shifted first
+     *
+     * @return a {@link java.lang.Integer} object.
+     */
+    Integer writeLsbFirst();
+
+    /**
+     * <p>getreadLsbfISRT.</p>
+     *
+     * @return a {@link java.lang.Integer} object.
+     */
+    default Integer getWriteLsbFirst() { return writeLsbFirst(); }
+
+
+
     /**
      * <p>bus.</p>
      * <p>If the Bus value is configured, that SpiBus
@@ -100,6 +142,36 @@ default boolean getBusUserProvided(){
         return busUserProvided();
     }
 
+    /**
+     * <p>writeLsbFirstserProvided.</p>
+     * @return  a boolean.
+     */
+    boolean writeLsbFirstUserProvided();
+
+    /**
+     * <p>getWriteLsbFirstUserProvided.</p>
+     * @return  a {@link java.lang.Boolean} object.
+     */
+    default boolean getWriteLsbFIrstUserProvided(){
+        return writeLsbFirstUserProvided();
+    }
+
+    /**
+     * <p>writeLsbFirstserProvided.</p>
+     * @return  a boolean.
+     */
+    boolean readLsbFirstUserProvided();
+
+    /**
+     * <p>getReadLsbFirstUserProvided.</p>
+     * @return  a {@link java.lang.Boolean} object.
+     */
+    default boolean getReadLsbFIrstUserProvided(){
+        return readLsbFirstUserProvided();
+    }
+
+
+
 
     /**
      * <p>mode.</p>

pi4j-core/src/main/java/com/pi4j/io/spi/SpiConfigBuilder.java

@@ -47,6 +47,24 @@ static SpiConfigBuilder newInstance(Context context)  {
         return DefaultSpiConfigBuilder.newInstance(context);
     }
 
+    /**
+     * <p>readLsbFirst.</p>
+     *
+     * @param shift  a {@link java.lang.Integer} object.
+     * @return a {@link com.pi4j.io.spi.SpiConfigBuilder} object.
+     */
+    SpiConfigBuilder readLsbFirst(Integer shift);
+
+    /**
+     * <p>writeLsbFirst.</p>
+     *
+     * @param shift  a {@link java.lang.Integer} object.
+     * @return a {@link com.pi4j.io.spi.SpiConfigBuilder} object.
+     */
+    SpiConfigBuilder writeLsbFirst(Integer shift);
+
+
+
     /**
      * <p>baud.</p>
      *
@@ -55,6 +73,7 @@ static SpiConfigBuilder newInstance(Context context)  {
      */
     SpiConfigBuilder baud(Integer rate);
 
+
     /**
      * <p>bus.</p>
      * <p>If the Bus value is configured, that SpiBus

pi4j-core/src/main/java/com/pi4j/io/spi/impl/DefaultSpiConfig.java

@@ -48,6 +48,10 @@ public class DefaultSpiConfig
     protected final SpiBus bus;
     protected boolean busUserProvided = false;  // indicate user supplied the value
     protected final Long flags;
+    protected final int readLsbFirst;
+    protected final int writeLsbFirst;
+    protected boolean readLsbFirstUserProvided;
+    protected boolean writeLsbFirstUserProvided;
 
     /**
      * PRIVATE CONSTRUCTOR
@@ -73,6 +77,20 @@ protected DefaultSpiConfig(Map<String,String> properties){
             this.busUserProvided = false;
         }
 
+        if(properties.containsKey(WRITE_LSB_KEY)){
+            this.writeLsbFirst = StringUtil.parseInteger(properties.get(WRITE_LSB_KEY),Spi.DEFAULT_WRITE_LSB_FIRST);
+            this.writeLsbFirstUserProvided = true;
+        }else {
+            this.writeLsbFirst = 0;
+            this.writeLsbFirstUserProvided = false;
+        }
+        if(properties.containsKey(READ_LSB_KEY)){
+            this.readLsbFirst = StringUtil.parseInteger(properties.get(READ_LSB_KEY),Spi.DEFAULT_READ_LSB_FIRST);
+            this.readLsbFirstUserProvided = true;
+        }else {
+            this.readLsbFirst = 0;
+            this.readLsbFirstUserProvided = false;
+        }
         // load optional MODE from properties
         if(properties.containsKey(MODE_KEY)){
             this.mode = SpiMode.parse(properties.get(MODE_KEY));
@@ -86,7 +104,7 @@ protected DefaultSpiConfig(Map<String,String> properties){
         if(properties.containsKey(FLAGS_KEY)){
             this.flags = StringUtil.parseLong(properties.get(FLAGS_KEY), null);
         } else {
-            this.flags = 0L; // default flags (0)
+            this.flags = null; // set null, same as parseLong would
         }
 
         // define default property values if any are missing (based on the required address value)
@@ -101,13 +119,34 @@ public Integer baud() {
         return this.baud;
     }
 
+    @Override
+    public Integer readLsbFirst() {
+        return this.readLsbFirst;
+    }
+
+    @Override
+    public Integer writeLsbFirst() {
+        return this.writeLsbFirst;
+    }
+
     /** {@inheritDoc} */
     @Override
     public boolean busUserProvided() {
         return this.busUserProvided;
     }
 
 
+    /** {@inheritDoc} */
+    @Override
+    public boolean writeLsbFirstUserProvided() {
+        return this.writeLsbFirstUserProvided;
+    }
+    /** {@inheritDoc} */
+    @Override
+    public boolean readLsbFirstUserProvided() {
+        return this.readLsbFirstUserProvided;
+    }
+
 
     /** {@inheritDoc} */
     @Override

pi4j-core/src/main/java/com/pi4j/io/spi/impl/DefaultSpiConfigBuilder.java

@@ -56,6 +56,18 @@ public static SpiConfigBuilder newInstance(Context context) {
         return new DefaultSpiConfigBuilder(context);
     }
 
+    @Override
+    public SpiConfigBuilder readLsbFirst(Integer shift) {
+        this.properties.put(SpiConfig.READ_LSB_KEY, shift.toString());
+        return this;
+    }
+
+    @Override
+    public SpiConfigBuilder writeLsbFirst(Integer shift) {
+        this.properties.put(SpiConfig.WRITE_LSB_KEY, shift.toString());
+        return this;
+    }
+
     /** {@inheritDoc} */
     @Override
     public SpiConfigBuilder baud(Integer rate) {

plugins/pi4j-plugin-linuxfs/pom.xml

@@ -21,6 +21,11 @@
             <artifactId>jsch</artifactId>
             <version>${jsch.version}</version>
         </dependency>
+        <dependency>
+            <groupId>net.java.dev.jna</groupId>
+            <artifactId>jna</artifactId>
+            <version>${jna.version}</version>
+        </dependency>
         <dependency>
             <groupId>com.pi4j</groupId>
             <artifactId>pi4j-library-linuxfs</artifactId>

plugins/pi4j-plugin-linuxfs/src/main/java/com/pi4j/plugin/linuxfs/LinuxFsPlugin.java

@@ -37,6 +37,7 @@
 import com.pi4j.plugin.linuxfs.provider.gpio.digital.LinuxFsDigitalOutputProvider;
 import com.pi4j.plugin.linuxfs.provider.pwm.LinuxFsPwmProvider;
 import com.pi4j.plugin.linuxfs.internal.LinuxPwm;
+import com.pi4j.plugin.linuxfs.provider.spi.LinuxFsSpiProvider;
 import com.pi4j.provider.Provider;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -100,14 +101,15 @@ public class LinuxFsPlugin implements Plugin {
     public static final String I2C_PROVIDER_NAME = NAME + " I2C Provider";
     public static final String I2C_PROVIDER_ID = ID + "-i2c";
 
-//    // SPI Provider name and unique ID
-//    public static final String SPI_PROVIDER_NAME = NAME + " SPI Provider";
-//    public static final String SPI_PROVIDER_ID = ID + "-spi";
-//
+
 //    // Serial Provider name and unique ID
 //    public static final String SERIAL_PROVIDER_NAME = NAME + " Serial Provider";
 //    public static final String SERIAL_PROVIDER_ID = ID + "-serial";
 
+    // SPI Provider name and unique ID
+    public static final String SPI_PROVIDER_NAME = NAME + " SPI Provider";
+    public static final String SPI_PROVIDER_ID = ID + "-spi";
+
     public static String DEFAULT_GPIO_FILESYSTEM_PATH = LinuxGpio.DEFAULT_SYSTEM_PATH;
     public static String DEFAULT_PWM_FILESYSTEM_PATH = LinuxPwm.DEFAULT_SYSTEM_PATH;
 
@@ -155,7 +157,8 @@ public void initialize(PluginService service) {
             LinuxFsDigitalInputProvider.newInstance(gpioFileSystemPath),
             LinuxFsDigitalOutputProvider.newInstance(gpioFileSystemPath),
             LinuxFsPwmProvider.newInstance(pwmFileSystemPath, pwmChip),
-            LinuxFsI2CProvider.newInstance()
+            LinuxFsI2CProvider.newInstance(),
+            LinuxFsSpiProvider.newInstance()
         };
 
         // register the LinuxFS I/O Providers with the plugin service

plugins/pi4j-plugin-linuxfs/src/main/java/com/pi4j/plugin/linuxfs/internal/LinuxLibC.java

@@ -0,0 +1,84 @@
+/*
+ *    * Copyright (C) 2012 - 2024 Pi4J
+ *  * %%
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ * -
+ *  #%L
+ *  **********************************************************************
+ *  ORGANIZATION  :  Pi4J
+ *  PROJECT       :  Pi4J :: EXTENSION
+ *  FILENAME      :  LinuxLibC.java
+ *
+ *  This file is part of the Pi4J project. More information about
+ *  this project can be found here:  https://pi4j.com/
+ *  **********************************************************************
+ *  %%
+ */
+
+package com.pi4j.plugin.linuxfs.internal;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+
+/**
+ * C library functions.
+ *
+ * @author mpilone
+ * @since 10/3/24.
+ */
+public interface LinuxLibC extends Library {
+
+    LinuxLibC INSTANCE = LinuxLibC.LibLoader.load();
+
+    class LibLoader {
+        static LinuxLibC load() {
+            return Native.load("c", LinuxLibC.class);
+        }
+    }
+
+    ///////////////////////////////////
+    // fcntl.h
+    int O_WRONLY = 00000001;
+    int O_RDWR = 00000002;
+    int O_NONBLOCK = 00004000;
+
+    ///////////////////////////////////
+    // ioctl.h
+    int _IOC_NRBITS = 8;
+    int _IOC_TYPEBITS = 8;
+    int _IOC_SIZEBITS = 14;
+
+    int _IOC_NRSHIFT = 0;
+    int _IOC_TYPESHIFT = (_IOC_NRSHIFT + _IOC_NRBITS);
+    int _IOC_SIZESHIFT = (_IOC_TYPESHIFT + _IOC_TYPEBITS);
+    int _IOC_DIRSHIFT = (_IOC_SIZESHIFT + _IOC_SIZEBITS);
+
+    byte _IOC_NONE = 0;
+    byte _IOC_WRITE = 1;
+    byte _IOC_READ = 2;
+
+    static int _IOC(byte dir, byte type, byte nr, int size) {
+        return (((dir) << _IOC_DIRSHIFT) |
+            ((type) << _IOC_TYPESHIFT) |
+            ((nr) << _IOC_NRSHIFT) |
+            ((size) << _IOC_SIZESHIFT));
+    }
+
+    int ioctl(int filedes, long op, Object... args);
+
+    int open(String pathname, int flags);
+
+    int close(int fd);
+}