AM335x EVM On-Board Components Drivers Guide

AM335x EVM On-Board Components Drivers Guide

Linux PSP

Introduction

This wiki page provides the information on On-Board Component Driver details of AM335x EVM.

Accelerometer

LIS331DLH from ST Microelectronics is present on the AM335x daughter card, placed exactly at the center of the board for giving proper acceleration values. LIS331DLH is placed under lis3lv02d family. This driver provides input events as well as sysfs attributes.

Position

3D position that accelerometer reports in the format of (x, y, z)

$ cat /sys/devices/platform/lis3lv02d/position

Reported values are scaled to mg values (1/1000 of earth gravity). In the driver 1024 LSBs corresponds 1g -> 1LSB is 1000/1024 mg

Rate

Reports the sampling rate of the accelerometer device in HZ.

$ cat /sys/devices/platform/lis3lv02d/rate

This parameter can be configurable by the user to different rates, LIS331DLH supports 50, 100, 400 and 1000

$ echo 100 > /sys/devices/platform/lis3lv02d/rate

Range

LIS331DLH has dynamically user selectable full scales of +/-2, +/-4 and +/-8g

$ cat /sys/devices/platform/lis3lv02d/range

$ echo 2 > /sys/devices/platform/lis3lv02d/range

Kernel Configuration

Accelerometer driver is enabled by default in am335x_evm_defconfig. To enable/disable Accelerometer driver support, start the Linux Kernel Configuration tool:

$ make menuconfig ARCH=arm

Select Device Drivers from the main menu.

    ...
    ...
    Power management options --->
[*] Networking support --->
    Device Drivers --->
    File systems --->
    Kernel hacking --->
    ...
    ...

Select Misc devices from the Device Drivers menu.

    ...
    ...
<*> Memory Technology Device (MTD) support  --->
    Device Tree and Open Firmware support  --->  
< > Parallel port support  --->
[*] Block devices  --->
[*] Misc devices  --->
< > ATA/ATAPI/MFM/RLL support (DEPRECATED)  --->
    SCSI device support  --->
    ...
    ...

Select STMicroeletronics LIS3LV02Dx three-axis digital accelerometer (I2C) from the menu.

    ...
    ...
< > Intel Wireless MultiCom Top Driver
    Texas Instruments shared transport line discipline  --->
< > STMicroeletronics LIS3LV02Dx three-axis digital accelerometer (SPI)
<*> STMicroeletronics LIS3LV02Dx three-axis digital accelerometer (I2C)
    ...
    ...

Temperature Sensor

TMP275, digital temperature sensor is used as a temperature sensor for reporting the current temperature of the Board.

Temp1_input

Sysfs attribute specifies the current temperature.

$ cat /sys/bus/i2c/drivers/lm75/2-0048/temp1_input

Reported values are Degree Centigrade * 1000

Temp1_max

Sysfs attribute specifies the maximum temperature of the Board.

$ cat /sys/bus/i2c/drivers/lm75/2-0048/temp1_max

Temp1_max_hyst

Sysfs attribute specifies the maximum temperature hysterics of the Board.

$ cat /sys/bus/i2c/drivers/lm75/2-0048/temp1_max_hyst

Kernel Configuration

Temperature Sensor driver is enabled by default in am335x_evm_defconfig. To enable/disable Temperature Sensor driver support, start the Linux Kernel Configuration tool:

$ make menuconfig ARCH=arm

Select Device Drivers from the main menu.

    ...
    ...
    Power management options --->
[*] Networking support --->
    Device Drivers --->
    File systems --->
    Kernel hacking --->
    ...
    ...

Select Hardware Monitoring support from the Device Drivers menu.

    ...
    ...
< > Dallas's 1-wire support  --->
< > Power supply class support  --->
<*> Hardware Monitoring support  --->
< > Generic Thermal sysfs driver  --->
    ...
    ...

Select National Semiconductor LM75 and compatibles from the menu.

    ...
    ...
< > National Semiconductor LM70 / Texas Instruments TMP121
< > National Semiconductor LM73
<*> National Semiconductor LM75 and compatibles
< > National Semiconductor LM77
< > National Semiconductor LM78 and compatibles
    ...
    ...

Ambient Light Sensor

TAOS - TSL2550, Ambient Light sensor is used as a Light sensor for reporting the current luminous intensity.

Lux1_input

Sysfs attribute specifies the current luminous intensity.

$ cat /sys/bus/i2c/drivers/tsl2550/2-0039/lux1_input

Kernel Configuration

Ambient Light Sensor driver is enabled by default in am335x_evm_defconfig. To enable/disable Ambient Light Sensor driver support, start the Linux Kernel Configuration tool:

$ make menuconfig ARCH=arm

Select Device Drivers from the main menu.

    ...
    ...
    Power management options --->
[*] Networking support --->
    Device Drivers --->
    File systems --->
    Kernel hacking --->
    ...
    ...

Select Misc devices from the Device Drivers menu.

    ...
    ...
<*> Memory Technology Device (MTD) support  --->
    Device Tree and Open Firmware support  --->  
< > Parallel port support  --->
[*] Block devices  --->
[*] Misc devices  --->
< > ATA/ATAPI/MFM/RLL support (DEPRECATED)  --->
    SCSI device support  --->
    ...
    ...

Select Taos TSL2550 ambient light sensor from the menu.

    ...
    ...
< > Intersil ISL29003 ambient light sensor
< > Intersil ISL29020 ambient light sensor
<*> Taos TSL2550 ambient light sensor
< > ROHM BH1780GLI ambient light sensor 
    ...
    ...