OWLL(9)

🌈 OWLL(9) — the Kernel Developer's Manual page, bestie edition 🌈

okay so this is owll(9) from the Kernel Developer's Manual, and we're about to get so cozy with the Dallas Semiconductor 1-Wire Link Layer Interface. it's giving low-level but make it cute 💅

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✨ NAME ✨

owll, OWLL_WRITE_ONE, OWLL_WRITE_ZERO, OWLL_READ_DATA, OWLL_REASET_AND_PRESENCE — Dallas Semiconductor 1-Wire Link Layer Interface 🦋

(yes, <italic>REASET</italic> is spelled exactly like that in the NAME section, and yes, it's spelled OWLL_RESET_AND_PRESENCE down in SYNOPSIS. she contains multitudes 💀)

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⭐ SYNOPSIS ⭐

int
OWLL_WRITE_ONE(device_t lldev, struct ow_timing *timing);

int
OWLL_WRITE_ZERO(device_t lldev, struct ow_timing *timing);

int
OWLL_READ_DATA(device_t lldev, struct ow_timing *timing, int *bit);

int
OWLL_RESET_AND_PRESENCE(device_t lldev, struct ow_timing *timing,
    int *bit);

look at those signatures, so clean, so crisp, we love a consistent return type 👑

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💖 DESCRIPTION 💖

so the owll interface is literally your backstage pass 🎟️ — it gives the upper layers of the protocol access to the link layer of the Dallas Semiconductor 1-Wire. it's the plumbing, and honestly? iconic.

OWLL_WRITE_ONE() and OWLL_WRITE_ZERO() write a one bit or a zero bit respectively on the 1-Wire bus. that's it, that's the whole vibe — one function per bit, no notes. 🫶

OWLL_READ_DATA() reads one bit from the 1-Wire bus. the 1-Wire device data sheets call this a "Read Time Slot", so if you see that phrase in the docs, that's this function. iykyk 📖✨

the OWLL_RESET_AND_PRESENCE() function starts a reset sequence and detects if any device(s) are present on the bus. and here's the main character energy: this is the beginning of all 1-Wire transactions. every single one. no cap. 🔥

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🎀 NOTES 🎀

• 🚨 this interface is intended to be used only by the ow(4) device to talk to the low-level bus.
• by convention, the device that implements this interface is called owc(4).
• only devices that implement own(9) should call these interfaces.

bestie, read that again — only ow(4), only things implementing own(9). don't be the one who breaks the convention, we're all counting on you 🙈

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🦋 SEE ALSO 🦋

• ow(4)
• owc(4)
• own(9)

go read those, they're the supporting cast and they ate 💜

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⚖️ LEGAL ⚖️

1-Wire is a registered trademark of Maxim Integrated Products, Inc. gotta respect the trademark, periodt 🌸

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🌸 HISTORY 🌸

the owll driver first appeared in FreeBSD 11.0. a legend was born ✨

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👑 AUTHORS 👑

the owll device driver and this manual page were written by Warner Losh. thank you for your service, king 🫡💖

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and that's the whole page, bestie — this one's from Debian, dated September 22, 2016, and we're closing it out with the biggest 🎀💜⭐ vibes. stay bit-flippin' out there, and remember: reset first, then party 🧚✨