spi_setup(9)

📦 version 7.3.1, in nixpkgs unstable

✨ NAME ✨

okay bestie, this is spi_setup(9) from the Kernel API Manual 💖 and it's literally here to setup SPI mode and clock rate. That's the whole assignment, no cap.

🌸 SYNOPSIS 🌸

int spi_setup (struct spi_device *spi );

🫶 ARGUMENTS 🫶

  • spi — the device whose settings are being modified. main character device energy 🎀

💤 CONTEXT 💤

Context vibe check: can sleep, and no requests are queued to the device 😴✨

🔥 DESCRIPTION 🔥

okay so SPI protocol drivers may need to update the transfer mode if the device doesn't work with its default. They may likewise need to update clock rates or word sizes from initial values. This function changes those settings, and must be called from a context that can sleep. no exceptions, bestie 💅

Except for SPI_CS_HIGH, which takes effect immediately, the changes take effect the next time the device is selected and data is transferred to or from it. When this function returns, the SPI device is deselected. the way that's literally the cleanup moment 🫶

Note: this call will fail if the protocol driver specifies an option that the underlying controller or its driver does not support. For example, not all hardware supports wire transfers using nine bit words, LSB-first wire encoding, or active-high chipselects. not every controller ate that assignment, and that's valid 😭

🎯 RETURN 🎯

It's giving zero on success, else a negative error code — slay when it's zero, sigh when it's negative 💚

👀 SEE ALSO 👀

Kernel file ./drivers/spi/spi.c and __spi_register_driver(9), plus the whole squad:

mwah 💋 — source/version vibe: ./drivers/spi; dated October 2026; page: spi_setup(9). byeeee 🦋

📦 where this page comes from