Linux/AM3352: Setting ADC sysfs

WTMEC_Will Hsu

Expert 2620 points

Part Number: AM3352

Tool/software: Linux

Hi TT team,

I'm testing ADC function of AM3352.

I have tried to set some value and keyword as [FIG1] to control in /sys/bus/iio/devices/iio:device0/power.

But I got “write error: Invalid argument”.

Could you help me to provide the key word for me to power off the ADC?

Because I didn’t find the information to set control file.

Thanks.

[FIG1]

From Will Hsu

over 8 years ago

0 Yordan Kovachev over 8 years ago

TI__Guru**** 161600 points

Hi,

ADC user guide is here:
processors.wiki.ti.com/.../Linux_Core_ADC_Users_Guide

Which SDK are you using?

Best Regards,
Yordan

0 WTMEC_Will Hsu over 8 years ago in reply to Yordan Kovachev

Expert 2620 points

Hi Yordan,
Thank you for your reply.
The SDK which we use is ti-sdk-am335x-evm-08.00.00.00.
The ADC users guide is not enough for me.

How to set up "/sys/bus/iio/devices/iio\:device0/power"?
Could you help me to provide the key word for me to power off the ADC?

Thanks.

From Will

0 Jason Reeder over 8 years ago in reply to WTMEC_Will Hsu

TI__Genius 10440 points

Will,

The power sysfs interface that you are referencing is defined in the Linux kernel sources at drivers/base/power/sysfs.c and it is not specific to the ADC subsystem. This interface cannot be used to power off (or power on) the ADC.

To my knowledge there is no sysfs interface that is exposed that can power the ADC off or on. One method to reset the ADC would be direct register writes using the devmem2 utility (as Rio posted in your other thread: https://e2e.ti.com/support/arm/sitara_arm/f/791/t/610112).

Jason

P.S. The allowable values for the 'control' attribute are 'auto' or 'on' and they are described in the comment at the top of the drivers/base/power/sysfs.c file in the kernel sources.

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Linux/AM3352: Setting ADC sysfs