Cl-Spidev

About cl-spidev

This is a bindings library for the Linux SPIDEV kernel module as described on https://www.kernel.org/doc/Documentation/spi/spidev. It provides both direct low-level, and high-level convenient access.

How To

List all the available SPIDEV devices.

(spidev:devices)

Create a handle object to one of them.

(defvar *handle* (spidev:open "0.0"))

You can then read out the current information of the device.

(spidev:mode *handle*)
(spidev:lsb-first *handle*)
(spidev:bits/word *handle*)
(spidev:max-speed *handle*)

You can also set the above places to the values you need them to be. See the respective docstrings.

Finally you can read from and write to the device.

(spidev:read* 12 *handle*)
(spidev:write* *handle* 1 2 3 4)

Once you are done you can either close the handle explicitly...

(spidev:close *handle*)

Or simply lose all references to it and wait for the GC to take care of it for you. Either way, it should be safe.

Package Index

CL-SPIDEV-LLI (ORG.SHIRAKUMO.SPIDEV.LLI)

constant

`SPI-3WIRE`

Constant holding the value defined in the kernel constant SPI_3WIRE.

constant

`SPI-CPOL`

Constant holding the value defined in the kernel constant SPI_CPOL.

constant

`SPI-CS-HIGH`

Constant holding the value defined in the kernel constant SPI_CS_HIGH.

constant

`SPI-IOC-MESSAGE-1`

Constant holding the value defined in the kernel constant SPI_IOC_MESSAGE(1).

constant

`SPI-IOC-RD-BITS-PER-WORD`

Constant holding the value defined in the kernel constant SPI_IOC_RD_BITS_PER_WORD.

constant

`SPI-IOC-RD-LSB-FIRST`

Constant holding the value defined in the kernel constant SPI_IOC_RD_LSB_FIRST.

constant

`SPI-IOC-RD-MAX-SPEED-HZ`

Constant holding the value defined in the kernel constant SPI_IOC_RD_MAX_SPEED_HZ.

constant

`SPI-IOC-RD-MODE`

Constant holding the value defined in the kernel constant SPI_IOC_RD_MODE.

constant

`SPI-IOC-RD-MODE32`

Constant holding the value defined in the kernel constant SPI_IOC_RD_MODE32.

constant

`SPI-IOC-WR-BITS-PER-WORD`

Constant holding the value defined in the kernel constant SPI_IOC_WR_BITS_PER_WORD.

constant

`SPI-IOC-WR-LSB-FIRST`

Constant holding the value defined in the kernel constant SPI_IOC_WR_LSB_FIRST.

constant

`SPI-IOC-WR-MAX-SPEED-HZ`

Constant holding the value defined in the kernel constant SPI_IOC_WR_MAX_SPEED_HZ.

constant

`SPI-IOC-WR-MODE`

Constant holding the value defined in the kernel constant SPI_IOC_WR_MODE.

constant

`SPI-IOC-WR-MODE32`

Constant holding the value defined in the kernel constant SPI_IOC_WR_MODE32.

constant

`SPI-LOOP`

Constant holding the value defined in the kernel constant SPI_LOOP.

constant

`SPI-LSB-FIRST`

Constant holding the value defined in the kernel constant SPI_LSB_FIRST.

constant

`SPI-MODE-0`

Constant holding the value defined in the kernel constant SPI_MODE_0.

constant

`SPI-MODE-1`

Constant holding the value defined in the kernel constant SPI_MODE_1.

constant

`SPI-MODE-2`

Constant holding the value defined in the kernel constant SPI_MODE_2.

constant

`SPI-MODE-3`

Constant holding the value defined in the kernel constant SPI_MODE_3.

constant

`SPI-NO-CS`

Constant holding the value defined in the kernel constant SPI_NO_CS.

constant

`SPI-READY`

Constant holding the value defined in the kernel constant SPI_READY.

constant

`SPI-RX-DUAL`

Constant holding the value defined in the kernel constant SPI_RX_DUAL.

constant

`SPI-RX-QUAD`

Constant holding the value defined in the kernel constant SPI_RX_QUAD.

constant

`SPI-TX-DUAL`

Constant holding the value defined in the kernel constant SPI_TX_DUAL.

constant

`SPI-TX-QUAD`

Constant holding the value defined in the kernel constant SPI_TX_QUAD.

special

`SPIDEV-ROOT`

The root path for SPIDEV devices.
Should be /dev/

accessor (

`BITS/WORD`

HANDLE)

Accessor to how many bits there are per word on the SPIDEV device.

The value should be a positive integer, where 0 defaults to 8.

See IOCTL
See SPI-IOC-RD-BITS-PER-WORD
See SPI-IOC-WR-BITS-PER-WORD

accessor (

`LSB-FIRST`

HANDLE)

Accessor to whether the least significant byte comes first on the SPIDEV device.

The value should be T or NIL.

See IOCTL
See SPI-IOC-RD-LSB-FIRST
See SPI-IOC-WR-LSB-FIRST

accessor (

`MAX-SPEED`

HANDLE)

Accessor to the maximum speed frequency of the SPIDEV device in Hertz.

The value should be a positive integer. If it is too large and
the device refuses to adjust to it, a warning is signalled.

The actual rate in Hertz is returned.

See IOCTL
See SPI-IOC-RD-MAX-SPEED-HZ
See SPI-IOC-WR-MAX-SPEED-HZ

accessor (

`MODE`

HANDLE)

Accessor to the mode in which the SPIDEV device operates.

The value should be one of :MODE-0 :MODE-1 :MODE-2 :MODE-3 or
a specific mode integer.

See IOCTL
See SPI-IOC-WR-MODE32
See SPI-IOC-RD-MODE32
See SPI-MODE-0
See SPI-MODE-1
See SPI-MODE-2
See SPI-MODE-3

function (

`CLOSE-SPI`

HANDLE)

Close a handle to a SPIDEV device.

See WITH-OPEN-SPI

function (

`DEVICES`

)

Return a list of available SPIDEV devices on the system.

function (

`OPEN-SPI`

ID &KEY (DIRECTION :IO))

Open a handle to a SPIDEV device.

See WITH-OPEN-SPI

function (

`READ-BYTES`

BYTES HANDLE &KEY (START 0) END)

Reads a byte sequence from the SPIDEV device handle.

See LSB-FIRST
See BITS/WORD

function (

`TRANSMIT`

HANDLE BYTES SPEED-HZ DELAY-USECS BITS/WORD)

Perform a SPI transmission of the given byte sequence.

The array must be an unsigned-byte 8 array that is sharable.
On most implementations that matter this will correspond to
any simple-vector with element-type unsigned-byte 8.

The speed-hz, delay-usecs, and bits/word parameters are temp
overrides for the device configuration during the transmission.

Returned is a fresh vector of the same length as the bytes
vector, containing the contents of the read buffer of the
transmission.

See CFFI:MAKE-SHAREABLE-BYTE-VECTOR

function (

`WRITE-BYTES`

BYTES HANDLE &KEY (START 0) END)

Writes the byte sequence to the SPIDEV device handle.

See LSB-FIRST
See BITS/WORD

macro (

`WITH-OPEN-SPI`

(HANDLE ID &KEY (DIRECTION)) &BODY BODY)

Convenience wrapper to lexically retain a handle to a SPIDEV device.

See OPEN-SPI
See CLOSE-SPI

CL-SPIDEV (SPIDEV ORG.SHIRAKUMO.SPIDEV)

class

`HANDLE`

Struct to wrap a handle to a SPIDEV device and all of its associated information.

See OPEN
See CLOSE
See HANDLE
See MODE
See LSB-FIRST
See BITS/WORD
See MAX-SPEED
See READ
See READ*
See WRITE
See WRITE*

accessor (

`BITS/WORD`

INSTANCE)

Accessor to how many bits there are in a word on the device.

Should be an (UNSIGNED-BYTE 8) value.

See HANDLE

accessor (

`LSB-FIRST`

INSTANCE)

Accessor to whether the least significant byte comes first.

Should be a boolean.

See HANDLE

accessor (

`MAX-SPEED`

INSTANCE)

Accessor to the maximum transfer speed of the SPIDEV device in Hertz.

Should be an (UNSIGNED-BYTE 32) value.
The device may reject your requested speed, in which case a
warning is signalled and the actual speed is returned.

See HANDLE

accessor (

`MODE`

INSTANCE)

Accessor to the SPIDEV device's transfer mode.

The value should be one of :MODE-0 :MODE-1 :MODE-2 :MODE-3

See HANDLE

function (

`CLOSE`

HANDLE)

Safely closes the SPIDEV device. It becomes unusable after this.

See HANDLE

function (

`DEVICES`

)

Return a list of available SPIDEV devices on the system.

function (

`HANDLE`

INSTANCE)

Returns the underlying stream handle of the handle object.

This is useful when you need to interact with the low-level
system directly for some reason.

See HANDLE

function (

`OPEN`

ID)

Open a handle to a SPIDEV device.

This will produce a safe object that will always ensure the
underlying file-system handle is closed when the object is
no longer referenced. It will also cache the properties of
the underlying device, so read access to them should be fast.

See HANDLE

function (

`READ`

BYTES HANDLE &KEY (START 0) END)

Read a sequence of words from the SPIDEV device.

The bytes vector should be able to contain unsigned-bytes of
size up to the number of BITS/WORD of the handle.

See HANDLE
See READ*

function (

`READ*`

N HANDLE)

Read n words from the SPIDEV device into a fresh array.

See READ

function (

`TRANSMIT`

HANDLE BYTES &KEY SPEED DELAY BITS/WORD)

Perform a SPI transmission of the given byte sequence.

The array must be an unsigned-byte 8 array.

The speed-hz, delay-usecs, and bits/word parameters are temp
overrides for the device configuration during the transmission.
They default to MAX-SPEED, 0, and BITS/WORD respectively.

Returned is a fresh vector of the same length as the bytes
vector, containing the contents of the read buffer of the
transmission.

See HANDLE
See MAX-SPEED
See BITS/WORD

function (

`WRITE`

BYTES HANDLE &KEY (START 0) END)

Write a sequence of words to the SPIDEV device.

The bytes vector should contain unsigned-bytes of size up to
the number of BITS/WORD of the handle.

The bytes written are automatically flushed to the spi device
handle, so that when WRITE returns, the operation should have
completed. If you need to manually control flushing or need
to write in much smaller intervals, please refer to the low-
level interface.

See HANDLE
See WRITE*

function (

`WRITE*`

HANDLE &REST BYTES)

Writes the bytes in the arguments list to the SPIDEV device.

See WRITE

About cl-spidev

How To

Copyright

Package Index

CL-SPIDEV-LLI (ORG.SHIRAKUMO.SPIDEV.LLI)

CL-SPIDEV (SPIDEV ORG.SHIRAKUMO.SPIDEV)