sparse_keymap_setup(9)

💅 sparse_keymap_setup 💅

okay so bestie, you know how this page is from the Kernel API Manual and it's literally all about sparse_keymap_setup? yeah. that's the one. pull up a chair 🎀

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✨ NAME ✨

sparse_keymap_setup — set up a sparse keymap for an input device. that's it, that's the whole vibe 🦋

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🌸 SYNOPSIS 🌸

int sparse_keymap_setup (struct input_dev *dev , const struct key_entry
*keymap , int (*setup)(struct input_dev *, struct key_entry *) );

like, no cap, that's the whole signature. three arguments, one int coming back at you 💖

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🎀 ARGUMENTS 🎀

• dev — the input device. your main character, basically 👑
• keymap — the keymap, and the way it's shaped is an array of key_entry structures, and the very last one has to be a KE_END type entry. that last bit is not optional, it's the periodt of the array 🔥
• setup — a function you can use to adjust keymap entries depending on what the device needs. and hey, it may be NULL — yes queen, optional, we love that for you 🙈

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🦋 DESCRIPTION 🦋

okay so here's what happens, and it's actually iconic:

the function calculates the size and then allocates a copy of the original keymap — a copy, not your array, don't come for her — after which it sets up the input device event bits appropriately. slay. ⭐

and the allocated copy of the keymap is automatically freed when it is no longer needed. so you literally don't have to worry about it. she manages herself. self-care fr fr 🧚

ngl the freeing part is the best part. no cleanup code, no leaks, just vibes 💜

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/input/sparse-keymap.c
• sparse_keymap_entry_from_scancode(9)
• sparse_keymap_entry_from_keycode(9)
• sparse_keymap_report_entry(9)
• sparse_keymap_report_event(9)

go read those too, iykyk 🫶

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okay that's the page!! mwah 💋 and for the little sign-off credit-y bit at the bottom: this one lives under ./drivers/input and it's dated October 2026 — so like, future icon behaviour honestly. bye bestie, go set up some keymaps 💖✨🎀