Day14 - Event-Driven GPIO Driver

🧰 Build

make

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🚀 Load Driver

sudo insmod mygpio-irq.ko
dmesg | tail

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🔌 Device Node

ls -l /dev/mygpio

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💡 LED Control

echo led1=1 | sudo tee /dev/mygpio
echo led2=1 | sudo tee /dev/mygpio
echo all=0  | sudo tee /dev/mygpio

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🧪 Test 1: Blocking Read

cat /dev/mygpio

Expected:

• Waits for event
• Press button → prints one line
• Continues waiting

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🧪 Test 2: Single Event

head -n 1 /dev/mygpio

Expected:

• Exit after one event

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🧪 Test 3: Non-blocking Read

python3 test_nonblock.py

Expected:

• No event → EAGAIN
• Event → data returned

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🧪 Test 4: poll()

python3 test_poll.py

Expected:

• Wait for event
• Event triggers poll
• read() returns data

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🧪 Test 5: Rapid Press

• Press button quickly multiple times

Expected:

• Events queued
• Possible drops if buffer full

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⚠️ Module Removal

sudo rmmod mygpio_irq

Note:

• Will fail if device is open
• This is expected (module refcount)

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🧹 Unload

sudo rmmod mygpio_irq