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You're reading from  Linux Device Driver Development - Second Edition

Product typeBook
Published inApr 2022
PublisherPackt
ISBN-139781803240060
Edition2nd Edition
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Author (1)
John Madieu
John Madieu
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John Madieu

John Madieu is an embedded Linux and kernel engineer living in Paris, France. His main activities consist of developing device drivers and Board Support Packages (BSPs) for companies in domains such as IoT, automation, transport, healthcare, energy, and the military. John is the founder and chief consultant at LABCSMART, a company that provides training and services for embedded Linux and Linux kernel engineering. He is an open source and embedded systems enthusiast, convinced that it is only by sharing knowledge that we can learn more. He is passionate about boxing, which he practiced for 6 years professionally, and continues to channel this passion through training sessions that he provides voluntarily.
Read more about John Madieu

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Handling input devices from the user space

A node will be created in the /dev/input/ directory for each input device (polled or not) that has been successfully registered with the system. In my case, the node corresponds to event0 because it is the first and only input device on my target board. You can use the udevadm tool to display information about the device:

# udevadm info /dev/input/event0 
P: /devices/platform/input-button.0/input/input0/event0
N: input/event0
S: input/by-path/platform-input-button.0-event
E: DEVLINKS=/dev/input/by-path/platform-input-button.0-event
E: DEVNAME=/dev/input/event0
E: DEVPATH=/devices/platform/input-button.0/input/input0/event0
E: ID_INPUT=1
E: ID_PATH=platform-input-button.0
E: ID_PATH_TAG=platform-input-button_0
E: MAJOR=13
E: MINOR=64
E: SUBSYSTEM=input
E: USEC_INITIALIZED=74842430

Another tool that you can use, which allows you to print the keys that are supported by the device, is evetest. It can also catch and print events when they...

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Linux Device Driver Development - Second Edition
Published in: Apr 2022Publisher: PacktISBN-13: 9781803240060

Author (1)

author image
John Madieu

John Madieu is an embedded Linux and kernel engineer living in Paris, France. His main activities consist of developing device drivers and Board Support Packages (BSPs) for companies in domains such as IoT, automation, transport, healthcare, energy, and the military. John is the founder and chief consultant at LABCSMART, a company that provides training and services for embedded Linux and Linux kernel engineering. He is an open source and embedded systems enthusiast, convinced that it is only by sharing knowledge that we can learn more. He is passionate about boxing, which he practiced for 6 years professionally, and continues to channel this passion through training sessions that he provides voluntarily.
Read more about John Madieu