cdns_unprepa...fer_hardware(9)

💅 cdns_unprepare_transfer_hardware — the kernel API manual, but make it make sense

okay bestie, so this page lives in the Kernel API Manual, and the star of the show is literally cdns_unprepare_transfer_hardware(9). It's not long, it's not scary, and honestly? It's kind of a vibe. Let's get into it ✨

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🌸 NAME 🌸

cdns_unprepare_transfer_hardware — relaxes hardware after transfer 🫶

Like, the transfer is done, the party's over, and this function is the one turning off the lights and telling the SPI host to chill.

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✨ SYNOPSIS ✨

int cdns_unprepare_transfer_hardware (struct spi_controller *ctlr );

That's it. One function, one argument, returns an int. Clean. Minimal. Iconic. 💅

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🎀 ARGUMENTS 🎀

• ctlr — a pointer to the spi_controller structure, which is the thing that provides information about the controller. It's giving "here's my whole backstory" energy — hand it the struct and it knows what's up. 🦋

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🔥 DESCRIPTION 🔥

So this function does two whole things, and ngl they're both pretty important:

• It disables the SPI host controller when no target is selected. No target? No host controller running around doing cardio for nothing. It's called ✨ rest ✨.
• It flushes out any pending data in the FIFO. Anything still hanging around in there gets cleared out — no lingering leftovers, no awkward "wait were we still mid-transfer?" moments. 🧹

Main character energy honestly. It prepares the going back to sleep part of the lifecycle, and there's a matching cdns_prepare_transfer_hardware on the other side of the door (more on that in SEE ALSO 👀).

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💀 RETURN 💀

0 — always. Every single time. No errors, no surprises, no dramatic twist ending. It just returns 0 and goes about its day. fr fr. 🙈

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🌈 SEE ALSO 🌈

Bestie, the whole squad is here — every one of these shows up in the kernel file ./drivers/spi/spi-cadence.c, and you're gonna want to get acquainted:

• struct cdns_spi(9)
• cdns_spi_init_hw(9)
• cdns_spi_chipselect(9)
• cdns_spi_config_clock_mode(9)
• cdns_spi_config_clock_freq(9)
• cdns_spi_setup_transfer(9)
• cdns_spi_process_fifo(9)
• cdns_spi_irq(9)
• cdns_transfer_one(9)
• cdns_prepare_transfer_hardware(9)
• cdns_spi_detect_fifo_depth(9)
• cdns_target_abort(9)
• cdns_spi_probe(9)
• cdns_spi_remove(9)
• cdns_spi_suspend(9)
• cdns_spi_resume(9)
• cdns_spi_runtime_resume(9)
• cdns_spi_runtime_suspend(9)

iykyk 👑

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Quick vibe check before you close this tab: this page comes out of ./drivers/spi, and it's dated October 2026. Go forth and un-prepare that hardware, queen. 🎀✨💖