/*

* Copyright (c) Steven P. Goldsmith. All rights reserved.

*/

package com.codeferm.periphery;

import static com.codeferm.periphery.Common.MAX_CHAR_ARRAY_LEN;

import static com.codeferm.periphery.Common.jString;

import static com.codeferm.periphery.Common.memMove;

import static org.fusesource.hawtjni.runtime.FieldFlag.CONSTANT;

import org.fusesource.hawtjni.runtime.JniClass;

import org.fusesource.hawtjni.runtime.JniField;

import org.fusesource.hawtjni.runtime.JniMethod;

import org.fusesource.hawtjni.runtime.Library;

import static org.fusesource.hawtjni.runtime.MethodFlag.CONSTANT_INITIALIZER;

/**

* c-periphery SPI wrapper functions for Linux userspace spidev devices.

*

* @author Steven P. Goldsmith

* @version 1.0.0

* @since 1.0.0

*/

@JniClass

public class Spi implements AutoCloseable {

/**

* Function was successful.

*/

public static final int SPI_SUCCESS = 0;

/**

* java-periphery library.

*/

private static final Library LIBRARY = new Library("java-periphery", Spi.class);

/**

* SPI handle.

*/

final private long handle;

/**

* Load library.

*/

static {

LIBRARY.load();

init();

}

/**

* Load constants.

*/

@JniMethod(flags = {CONSTANT_INITIALIZER})

private static native void init();

/**

* Error constants.

*/

@JniField(flags = {CONSTANT})

public static int SPI_ERROR_ARG;

@JniField(flags = {CONSTANT})

public static int SPI_ERROR_OPEN;

@JniField(flags = {CONSTANT})

public static int SPI_ERROR_QUERY;

@JniField(flags = {CONSTANT})

public static int SPI_ERROR_CONFIGURE;

@JniField(flags = {CONSTANT})

public static int SPI_ERROR_TRANSFER;

@JniField(flags = {CONSTANT})

public static int SPI_ERROR_CLOSE;

/**

* Bit order constants.

*/

@JniField(flags = {CONSTANT})

public static int MSB_FIRST;

@JniField(flags = {CONSTANT})

public static int LSB_FIRST;

/**

* Open the spidev device at the specified path (e.g. "/dev/spidev1.0"), with the specified SPI mode, specified max speed in

* hertz, and the defaults of MSB_FIRST bit order, and 8 bits per word.

*

* @param path spidev path.

* @param mode Mode can be 0, 1, 2, or 3.

* @param maxSpeed Max speed in hertz.

*/

public Spi(final String path, final int mode, final int maxSpeed) {

// Allocate handle

handle = spiNew();

if (handle == 0) {

throw new RuntimeException("Handle cannot be NULL");

}

// Open device

if (spiOpen(handle, path, mode, maxSpeed) != SPI_SUCCESS) {

// Free handle before throwing exception

spiFree(handle);

throw new RuntimeException(spiErrMessage(handle));

}

}

/**

* Open the spidev device at the specified path, with the specified SPI mode, max speed in hertz, bit order, bits per word, and

* extra flags.

*

* SPI mode can be 0, 1, 2, or 3. Bit order can be MSB_FIRST or LSB_FIRST, as defined above. Bits per word specifies the

* transfer word size. Extra flags specified additional flags bitwise-ORed with the SPI mode.

*

* @param path spidev path.

* @param mode Mode can be 0, 1, 2, or 3.

* @param maxSpeed Max speed in hertz.

* @param bitOrder Bit order can be MSB_FIRST or LSB_FIRST.

* @param bitsPerWord Transfer word size.

* @param extraFlags Additional flags bitwise-ORed with the SPI mode.

*/

public Spi(final String path, final int mode, final int maxSpeed, final int bitOrder, final byte bitsPerWord,

final byte extraFlags) {

// Allocate handle

handle = spiNew();

if (handle == 0) {

throw new RuntimeException("Handle cannot be NULL");

}

// Open device

if (spiOpenAdvanced(handle, path, mode, maxSpeed, bitOrder, bitsPerWord, extraFlags) != SPI_SUCCESS) {

// Free handle before throwing exception

spiFree(handle);

throw new RuntimeException(spiErrMessage(handle));

}

}

/**

* Close and free handle.

*/

@Override

public void close() {

spiClose(handle);

spiFree(handle);

}

/**

* Handle accessor.

*

* @return Handle.

*/

public long getHandle() {

return handle;

}

/**

* Allocate an SPI handle.

*

* @return A valid handle on success, or NULL on failure.

*/

@JniMethod(accessor = "spi_new")

public static final native long spiNew();

/**

* Open the spidev device at the specified path (e.g. "/dev/spidev1.0"), with the specified SPI mode, specified max speed in

* hertz, and the defaults of MSB_FIRST bit order, and 8 bits per word.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param path spidev path.

* @param mode Mode can be 0, 1, 2, or 3.

* @param maxSpeed Max speed in hertz.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_open")

public static native int spiOpen(long spi, String path, int mode, int maxSpeed);

/**

* Open the spidev device at the specified path, with the specified SPI mode, max speed in hertz, bit order, bits per word, and

* extra flags.

*

* spi should be a valid pointer to an allocated SPI handle structure. SPI mode can be 0, 1, 2, or 3. Bit order can be MSB_FIRST

* or LSB_FIRST, as defined above. Bits per word specifies the transfer word size. Extra flags specified additional flags

* bitwise-ORed with the SPI mode.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param path spidev path.

* @param mode Mode can be 0, 1, 2, or 3.

* @param maxSpeed Max speed in hertz.

* @param bitOrder Bit order can be MSB_FIRST or LSB_FIRST.

* @param bitsPerWord Transfer word size.

* @param extraFlags Additional flags bitwise-ORed with the SPI mode.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_open_advanced")

public static native int spiOpenAdvanced(long spi, String path, int mode, int maxSpeed, int bitOrder, byte bitsPerWord,

byte extraFlags);

/**

* Open the spidev device at the specified path, with the specified SPI mode, max speed in hertz, bit order, bits per word, and

* extra flags. This open function is the same as spi_open_advanced(), except that extra_flags can be 32-bits.

*

* spi should be a valid pointer to an allocated SPI handle structure. SPI mode can be 0, 1, 2, or 3. Bit order can be MSB_FIRST

* or LSB_FIRST, as defined above. Bits per word specifies the transfer word size. Extra flags specified additional flags

* bitwise-ORed with the SPI mode.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param path spidev path.

* @param mode Mode can be 0, 1, 2, or 3.

* @param maxSpeed Max speed in hertz.

* @param bitOrder Bit order can be MSB_FIRST or LSB_FIRST.

* @param bitsPerWord Transfer word size.

* @param extraFlags Additional flags bitwise-ORed with the SPI mode.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_open_advanced2")

public static native int spiOpenAdvanced2(long spi, String path, int mode, int maxSpeed, int bitOrder, byte bitsPerWord,

int extraFlags);

/**

* Shift out len word counts of the txbuf buffer, while shifting in len word counts to the rxbuf buffer.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param txBuf Transmit buffer.

* @param rxBuf Receive buffer.

* @param len Word count.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_transfer")

public static native int spiTransfer(long spi, byte[] txBuf, byte[] rxBuf, long len);

/**

* Close the spidev device.

*

* @param spi Valid pointer to an allocated SPI handle structure.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_close")

public static native int spiClose(long spi);

/**

* Free an SPI handle.

*

* @param spi Valid pointer to an allocated SPI handle structure.

*/

@JniMethod(accessor = "spi_free")

public static native void spiFree(long spi);

/**

* Get the mode.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param mode Mode can be 0, 1, 2, or 3.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_get_mode")

public static native int spiGetMode(long spi, int[] mode);

/**

* Get the max speed.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param maxSpeed Max speed in hertz.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_get_max_speed")

public static native int spiGetMaxSpeed(long spi, int[] maxSpeed);

/**

* Get the bit order.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param bit_order Bit order can be MSB_FIRST or LSB_FIRST.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_get_bit_order")

public static native int spiGetBitOrder(long spi, int[] bit_order);

/**

* Get the bits per word.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param bitsPerWord Transfer word size.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_get_bits_per_word")

public static native int spiGetBitsPerWord(long spi, byte[] bitsPerWord);

/**

* Get extra flags.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param extraFlags Additional flags bitwise-ORed with the SPI mode.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_get_extra_flags")

public static native int spiGetExtraFlags(long spi, byte[] extraFlags);

/**

* Get extra flags.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param extraFlags Additional flags bitwise-ORed with the SPI mode.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_get_extra_flags32")

public static native int spiGetExtraFlags32(long spi, int[] extraFlags);

/**

* Set the mode.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param mode Mode can be 0, 1, 2, or 3.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_set_mode")

public static native int spiSetMode(long spi, int mode);

/**

* Set the max speed.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param maxSpeed Max speed in hertz.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_set_max_speed")

public static native int spiSetMaxSpeed(long spi, int maxSpeed);

/**

* Set the bit order.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param bit_order Bit order can be MSB_FIRST or LSB_FIRST.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_set_bit_order")

public static native int spiSetBitOrder(long spi, int bit_order);

/**

* Set the bits per word.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param bitsPerWord Transfer word size.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_set_bits_per_word")

public static native int spiSetBitsPerWord(long spi, byte bitsPerWord);

/**

* Set extra flags.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param extraFlags Additional flags bitwise-ORed with the SPI mode.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_set_extra_flags")

public static native int spiSetExtraFlags(long spi, byte extraFlags);

/**

* Set extra flags.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @param extraFlags Additional flags bitwise-ORed with the SPI mode.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_set_extra_flags32")

public static native int spiSetExtraFlags32(long spi, int extraFlags);

/**

* Return the file descriptor (for the underlying spidev device) of the SPI handle.

*

* @param spi A valid pointer to an allocated SPI handle structure.

* @return File descriptor (for the underlying spidev device) of the SPI handle.

*/

@JniMethod(accessor = "spi_fd")

public static native int spiFd(long spi);

/**

* Return a string representation of the SPI handle.

*

* @param spi Valid pointer to an allocated SPI handle structure.

* @param str String representation of the SPI handle.

* @param len Length of char array.

* @return 0 on success, or a negative SPI error code on failure.

*/

@JniMethod(accessor = "spi_tostring")

public static native int spiToString(long spi, byte[] str, long len);

/**

* Return a string representation of the SPI handle. Wraps native method and simplifies.

*

* @param spi Valid pointer to an allocated SPI handle structure.

* @return SPI handle as String.

*/

public static String spiToString(long spi) {

var str = new byte[MAX_CHAR_ARRAY_LEN];

if (spiToString(spi, str, str.length) < 0) {

throw new RuntimeException(spiErrMessage(spi));

}

return jString(str);

}

/**

* Return the libc errno of the last failure that occurred.

*

* @param spi Valid pointer to an allocated SPI handle structure.

* @return libc errno.

*/

@JniMethod(accessor = "spi_errno")

public static native int spiErrNo(long spi);

/**

* Return a human readable error message pointer of the last failure that occurred.

*

* @param spi Valid pointer to an allocated SPI handle structure.

* @return Error message pointer.

*/

@JniMethod(accessor = "spi_errmsg")

public static native long spiErrMsg(long spi);

/**

* Return a human readable error message of the last failure that occurred. Converts const char * returned by spi_errmsg to a

* Java String.

*

* @param spi Valid pointer to an allocated SPI handle structure.

* @return Error message.

*/

public static String spiErrMessage(long spi) {

var ptr = spiErrMsg(spi);

var str = new byte[MAX_CHAR_ARRAY_LEN];

memMove(str, ptr, str.length);

return jString(str);

}

}