Day35 - DRDY GPIO IRQ Integration

Objective

• Add DRDY GPIO signaling from STM32
• Configure Linux to receive GPIO interrupt
• Verify IRQ flow from sensor to driver

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Step 1 - STM32 DRDY Output

Ensure:

• GPIO configured as output
• idle = HIGH
• DRDY = LOW (pulse)

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Step 2 - Verify GPIO Pulse

Use:

• logic analyzer / oscilloscope
• or debug LED

Expected:

HIGH → LOW → HIGH (periodic)

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Step 3 - Device Tree Configuration

Add interrupt to I2C node:

interrupt-parent = <&rp1_gpio>;
interrupts = <23 2>;

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Step 4 - Verify IRQ Line

cat /proc/interrupts

Expected:

myadc_irq counter increases

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Step 5 - Load Driver

sudo insmod myadc_iio.ko
dmesg | tail

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Step 6 - Check IRQ Trigger

watch -n 1 'cat /proc/interrupts | grep myadc'

Expected:

counter increases continuously

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Step 7 - Check Driver Log

dmesg | grep myadc

Expected:

DRDY IRQ
DRDY IRQ

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Step 8 - Validate Data

cd /sys/bus/iio/devices/iio:device0

cat in_voltage0_raw
cat in_voltage1_raw
cat in_voltage2_raw

Expected:

• values change over time
• IRQ does not affect read correctness

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Result

Verified:

• DRDY pulse generation
• GPIO interrupt reception
• driver IRQ handling
• integration with IIO direct mode

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