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SAMA5D4 ADC driver - do you know a Linux image that has the driver?

Jan Cumps

For the Enchanted Objects Design ChallengeI'm trying to get the ADC Hardware Trigger mechanism working.


I have difficulties with the ADC driver. I am unsure if the 4.7 and 4.6 linux Yocto Poky images have that driver installed.


I have 3 questions :


Is the ADC driver for the sama5d4 included in those Yocto Poky images?

If yes, what's the name of the driver (is it at91_adc)?

If no, is there an image around with the ADC included, or is there a way to get the driver installed on my board running that Yocto Poky image?

 

Here's the blog post that shows what I'm dong: Review 9b: Atmel SMART SAMA5D4 Xplained Ultra - Set up ADC Buffer with Hardware Trigger Part 2

 

I have issues when the buffer read tool generic_buffer tries to load the driver:

 

Here's where the code fails:

 

    /* Find the device requested */  
    dev_num = find_type_by_name(device_name, "device");  
    if (dev_num < 0) {  
        printf("Failed to find the %s\n", device_name);  
        ret = -ENODEV;  
        goto error_ret;  
    }  
    printf("iio device number being used is %d\n", dev_num);

 

Error

Failed to find the at91_adc

Parents Reply Children
  • 0 in reply to noglitch

    Hi,

     

    That is the guide that I'm following.

    I managed to run the Software Triggered example without any issue. That just works perfectly.

     

    I'm also trying to run the Hardware Triggerd method of that page.

    All steps from the linux command line work, and I can see that there's data in the /dev/iio:device0 character device when I do cat /dev/iio:device0

     

    But when I try to run the tool generic_buffer (I compiled it from source, as explained under 'Testing the buffer' section on that page), it fails.

     

    I used these commands:

     

    modprobe at91_adc
echo 1 > /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage0_en
echo "fc034000.adc-dev0-continuous" > /sys/bus/iio/devices/iio:device0/trigger/current_trigger
echo 100 > /sys/bus/iio/devices/iio:device0/buffer/length
echo 1 > /sys/bus/iio/devices/iio:device0/buffer/enable

     

    When I run the self-compiled generic_buffer test tool, it fails when trying to find the device by the name 'at91_adc'

     

    ./generic_buffer -n at91_adc -t fc034000.adc-dev0-continuous -l 2

     

    Errors with 'Failed to find the at91_adc '.

     

    I'm not running from my own compiled distro , but have tried this process on the following two downloaded images:

    linux4sam-poky-sama5d4_xplained_hdmi-4.6

    and the new

    linux4sam-poky-sama5d4_xplained-4.7

  • 0 in reply to Jan Cumps

    Hi,

     

    Due to move to DT, the device name has changed. It is now "fc034000.adc" for this device. So, your command line should be:

    ./generic_buffer -n fc034000.adc -t fc034000.adc-dev0-continuous -l 2

     

    It seems to work on my side:

    root@sama5d4-xplained:~# ./generic_buffer -n fc034000.adc -t fc034000.adc-dev0-continuous -l 2
iio device number being used is 0
iio trigger number being used is 0
/sys/bus/iio/devices/iio:device0 fc034000.adc-dev0-continuous
281.000000 
280.000000 
274.000000 
274.000000

  • 0 in reply to noglitch

    Hi,

     

    I did try that,

    Your output is what I was expecting at my side too. I get a failure (using the 4.7.zip image at the moment)

     

    root@sama5d4-xplained:~# dmesg | grep  iio

    [    2.460000] iio iio:device0: Resolution used: 10 bits

    [    2.460000] iio iio:device0: ADC Touch screen is disabled.

     

     

     

    root@sama5d4-xplained:~# ./generic_buffer -n fc034000.adc -t fc034000.adc-dev0-continuous -l 2

    Failed to find the fc034000.adc