ADXL355

ADXL355 Low Noise, Low Drift, Low Power, 3-Axis MEMS Accelerometers.

Supported Devices

Evaluation Boards

Description

This is a Linux industrial I/O (Linux Industrial I/O Subsystem) subsystem driver, targeting serial interface accelerometers. The industrial I/O subsystem provides a unified framework for drivers for many different types of converters and sensors using a number of different physical interfaces (i2c, spi, etc). See Linux Industrial I/O Subsystem for more information.

Source Code

Status

Source

Mainlined?

git

Yes

Files

Function

File

core driver

drivers/iio/accel/adxl355_core.c

spi driver

drivers/iio/accel/adxl355_spi.c

i2c driver

drivers/iio/accel/adxl355_i2c.c

header

drivers/iio/accel/adxl355.h

Documentation

adi,adxl355.yaml

Example platform device initialization

Required devicetree properties:

  • compatible: Needs to be the name of the device. E.g. adi,adxl355

  • reg: the I2C address or SPI chip select number for the device

Required properties for SPI bus usage:

  • spi-max-frequency: Maximum SPI clock frequency.

Optional properties:

  • interrupts: a list of interrupt specifiers

Example for a SPI device node:

#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/interrupt-controller/irq.h>
spi {
        #address-cells = <1>;
        #size-cells = <0>;
        accelerometer@0 {
                compatible = "adi,adxl355";
                reg = <0>;
                spi-max-frequency = <1000000>;
                interrupt-parent = <&gpio>;
                interrupts = <25 IRQ_TYPE_EDGE_RISING>;
                interrupt-names = "DRDY";
        };
};

Example for a I2C device node:

i2c {
         #address-cells = <1>;
         #size-cells = <0>;
         /* Example for a I2C device node */
         accelerometer@1d {
                 compatible = "adi,adxl355";
                 reg = <0x1d>;
                 interrupt-parent = <&gpio>;
                 interrupts = <25 IRQ_TYPE_EDGE_RISING>;
                 interrupt-names = "DRDY";
         };
 };

Driver testing

root:/> cd /sys/bus/iio/devices/
root:/sys/bus/iio/devices> ls
iio:device0

root:/sys/bus/iio/devices> cd iio\:device0

root:/sys/bus/iio/devices/iio:device0> ls -l
drwxr-xr-x  2 root root    0 Nov 11 15:44 buffer
-rw-r--r--  1 root root 4096 Nov 11 15:44 current_timestamp_clock
-r--r--r--  1 root root 4096 Nov 11 15:44 dev
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_filter_high_pass_3db_frequency
-r--r--r--  1 root root 4096 Nov 11 15:44 in_accel_filter_high_pass_3db_frequency_available
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_sampling_frequency
-r--r--r--  1 root root 4096 Nov 11 15:44 in_accel_sampling_frequency_available
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_scale
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_x_calibbias
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_x_raw
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_y_calibbias
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_y_raw
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_z_calibbias
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_accel_z_raw
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_temp_offset
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_temp_raw
-rw-r--r--  1 root root 4096 Nov 11 15:44 in_temp_scale
-r--r--r--  1 root root 4096 Nov 11 15:44 name
drwxr-xr-x  2 root root    0 Nov 11 15:44 power
drwxr-xr-x  2 root root    0 Nov 11 15:44 scan_elements
lrwxrwxrwx  1 root root    0 Nov 11 15:44 subsystem -> ../../bus/iio
drwxr-xr-x  2 root root    0 Nov 11 15:44 trigger
-rw-r--r--  1 root root 4096 Nov 11 15:44 uevent

Show device name

root:/sys/bus/iio/devices/iio:device0> cat name
adxl355

Show scale

Description: scale to be applied to in_accel_*_raw in order to obtain the acceleration.

root:/sys/bus/iio/devices/iio:device0> cat in_accel_scale
0.000038245
Show axis x measurement

Description: Raw unscaled acceleration measurement on x axis

root:/sys/bus/iio/devices/iio:device0> cat in_accel_x_raw
-33631
Set sampling frequency
root:/sys/bus/iio/devices/iio:device0> cat in_accel_sampling_frequency_available
4000.000000 2000.000000 1000.000000 500.000000 250.000000 125.000000 62.500000 31.250000 15.625000 7.813000 3.906000

root:/sys/bus/iio/devices/iio:device0> cat in_accel_sampling_frequency
6400
root:/sys/bus/iio/devices/iio:device0> echo 4000 > in_accel_sampling_frequency
root:/sys/bus/iio/devices/iio:device0> cat in_accel_sampling_frequency
4000.000000
Show available bandwidths for the current set frequency
root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency_available
0.000000 9.880000 2.483360 0.621800 0.154480 0.038160 0.009520
root:/sys/bus/iio/devices/iio:device0>
Change the bandwidth
root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency_available
0.000000 9.880000 2.483360 0.621800 0.154480 0.038160 0.009520
root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency
0
root:/sys/bus/iio/devices/iio:device0> echo 0.621800 > in_accel_filter_low_pass_3db_frequency
root:/sys/bus/iio/devices/iio:device0> cat in_accel_filter_low_pass_3db_frequency
0.621800

Trigger management

root:/sys/bus/iio/devices/iio:device0> cat trigger/current_trigger
adxl355-dev-

Buffer management

Description: The scan_elements directory contains interfaces for elements that will be captured for a single triggered sample set in the buffer

root:/sys/bus/iio/devices/iio:device0/scan_elements> ls -l
-rw-r--r-- 1 root root 4096 Nov 11 15:44 in_accel_x_en
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_accel_x_index
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_accel_x_type
-rw-r--r-- 1 root root 4096 Nov 11 15:44 in_accel_y_en
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_accel_y_index
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_accel_y_type
-rw-r--r-- 1 root root 4096 Nov 11 15:44 in_accel_z_en
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_accel_z_index
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_accel_z_type
-rw-r--r-- 1 root root 4096 Nov 11 15:44 in_temp_en
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_temp_index
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_temp_type
-rw-r--r-- 1 root root 4096 Nov 11 15:44 in_timestamp_en
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_timestamp_index
-r--r--r-- 1 root root 4096 Nov 11 15:44 in_timestamp_type
root:/sys/bus/iio/devices/iio:device0/scan_elements>

root:/sys/bus/iio/devices/iio:device0/buffer> ls
data_available  enable  length  watermark
root:/sys/bus/iio/devices/iio:device0/buffer>

  • Set the buffer length:

root:/sys/bus/iio/devices/iio:device0/buffer> echo 1024 > length

  • Enable the buffer:

root:/sys/bus/iio/devices/iio:device0/buffer> echo 1 > enable

To read samples:

root:/sys/bus/iio/devices/iio:device0/buffer> cat /dev/iio:device0

More Information