gpiotools_request_line(9)

📦 version 7.3.1, in nixpkgs unstable

💖 gpiotools_request_line(9) 💖

okay bestie, so this is a page from the Kernel API Manual — yeah, that Kernel API Manual — and the star of the show is gpiotools_request_line(9), aka the little function that asks a gpiochip for some gpio lines. it's giving "may i please have some pins" energy and honestly? iconic.

✨ NAME ✨

gpiotools_request_line — request gpio lines in a gpiochip 🎀

🌸 SYNOPSIS 🌸

int gpiotools_request_line (const char *device_name , unsigned int
*lines , unsigned int num_lines , struct gpio_v2_line_config *config ,
const char *consumer );

like, look at that signature. five args. main character energy fr fr 💅

🦋 ARGUMENTS 🦋

  • device_name — the name of the gpiochip, and here's the thing: you do not put the "/dev/" prefix on it, okay? so it's like "gpiochip0", not the whole path. got it? 🫶
  • lines — an array of the lines you desire (manifesting them rn ✨), specified by offset index for the associated GPIO device.
  • num_lines — the number of lines you're requesting. yes, they have to match. no, you can't just wing it.
  • config — the new config for the requested gpio. for the config details, reference "linux/gpio.h" — go read it, it's right there, you got this 📖
  • consumer — the name of the consumer, such as "sysfs" or "powerkey". this one lowkey slays because it's useful for other users to know who is using the line. it's a little name tag for your line 😭🏷️

💜 DESCRIPTION 💜

so basically you request gpio lines through the ioctl provided by chardev. that's the whole vibe check.

after that, the user could call gpiotools_set_values and gpiotools_get_values to read and write respectively through the returned fd. read and write. both. the duality 👑

and then — important, bestie — call gpiotools_release_line to release these lines after that. don't just abandon them, that's so not the move 🙈

⭐ RETURN ⭐

  • on success: it returns the fd 🎉
  • on failure: it returns the errno 💀

🌈 SEE ALSO 🌈

periodt. that's the whole page. go request those lines, bestie 💅✨

🫶 and that's a wrap! this little masterpiece lives under ./tools/gpio, it's dated October 2026, and the whole thing answers to the name gpiotools_request_line(9). mwah 💋🎀

📦 where this page comes from