OWC(4)

💫 OWC(4) — Dallas Semiconductor 1-Wire Controller 💫

okay bestie, so this is the Kernel Interfaces Manual page for owc, and we're gonna get you fluent in it. no cap, it's shorter than it looks. 🦋

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🌸 NAME 🌸

owc — Dallas Semiconductor 1-Wire Controller

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✨ SYNOPSIS ✨

device owc

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💅 DESCRIPTION 💅

So the owc module is the one that actually implements Dallas Semiconductor 1-Wire signaling. It attaches the ow(4) driver 1-Wire bus protocol — like, it's the thing holding hands with it. And the owc device implements the Link Layer of the 1-Wire bus protocol stack. lowercase icon behavior honestly. 👑

Bit banging a pin on a gpiobus(4) is the only supported controller, periodt. Both standard and overdrive transfer timings are implemented. But the strong pull-up functionality needed to support parasitic mode is not implemented — so don't come for it, it's simply not there. 😭

If you wanna enable 1-Wire on FDT systems, you gotta modify the DTS for your board and add something like this:

/ {
        ...
        onewire {
                compatible = "w1-gpio";
                gpios = <&gpio 4 1>;
        };
        ...
};

The gpios property describes the GPIO pin the 1-Wire bus is connected to. For more details about the gpios property, please consult /usr/src/sys/dts/bindings-gpio.txt. (iykyk 📖)

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🎀 On a device.hints(5) based system 🎀

these values are required for the owc:

• hint.owc.%d.at — the gpiobus you are attaching to.
• hint.owc.%d.pins — this is a bitmask that defines a pin on the gpiobus that is to be used for the 1-Wire bus. For instance, to configure pin 10, use the bitmask of 0x400. Please note that this mask should have only one bit set (any other bits — i.e., pins — will be ignored). 🙈

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🫶 SEE ALSO 🫶

gpiobus(4), ow(4), ow_temp(4), owll(9), own(9)

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⚖️ LEGAL ⚖️

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

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📜 HISTORY 📜

The owc driver first appeared in FreeBSD 11.0.

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👑 AUTHORS 👑

The owc device driver and this manual page were written by Warner Losh. slay.

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🌈 CAVEATS 🌈

The gpio driver implements timing by busy waiting, which can cause a high load on slower systems. so like… heads up, bestie. 🔥

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💀 BUGS 💀

Overdrive mode has not actually been tested. not me exposing the driver like this 😭 fr fr, it's right there in the manpage.

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okay that's the whole vibe check, you're officially fluent in owc 💖✨

this page was brought to you by the Debian fam, dated June 26, 2019 — stay iconic, and go read the source, it's giving main character energy 🎀🦋💜