Day33 - Minimal IIO Driver

Objective

• Implement a minimal IIO driver
• Verify sysfs interface generation
• Understand read path mapping

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Step 1 - Build Driver

make

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Step 2 - Load IIO Core (if needed)

sudo modprobe industrialio

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Step 3 - Insert Module

sudo insmod myiio_dummy.ko

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Step 4 - Verify Probe

dmesg | tail -n 20

Expected:

myiio_dummy: module loaded
myiio probe start

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Step 5 - Check IIO Device

ls /sys/bus/iio/devices/

Expected:

iio:device0

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Step 6 - Explore sysfs

cd /sys/bus/iio/devices/iio:device0
find . | sort

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Step 7 - Read Values

cat name
cat in_voltage0_raw
cat in_voltage0_scale

Expected:

myiio_dummy
1234
0.001000

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Step 8 - Modify Raw Value

Edit:

static int fake_adc_value = 2048;

Rebuild and reload:

make
sudo rmmod myiio_dummy
sudo insmod myiio_dummy.ko

Verify:

cat in_voltage0_raw

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Step 9 - Remove SCALE Attribute (Optional)

Modify:

.info_mask_separate = BIT(IIO_CHAN_INFO_RAW);

Reload driver and verify:

ls

Expected:

in_voltage0_raw

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Result

Successfully verified:

• sysfs auto-generation
• channel mapping
• read_raw() data path

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