bcm2835_spi_prepare_sg(9)

📦 version 7.3.1, in nixpkgs unstable

💅 bcm2835_spi_prepare_sg — a page from the Kernel API Manual ✨

okay bestie, buckle up, we're doing kernel SPI DMA today and honestly? it's giving main character energy 🎀 this is the man page for bcm2835_spi_prepare_sg(9), straight out of the Kernel API Manual, and yes you're gonna understand it. periodt.

🌸 NAME 🌸

bcm2835_spi_prepare_sg — the girl who prepares and submits the DMA descriptor for the sglist 🦋 both jobs, one function, she's booked and busy.

✨ SYNOPSIS ✨

int bcm2835_spi_prepare_sg (struct spi_controller *ctlr , struct
       spi_transfer *tfr , struct bcm2835_spi *bs , struct bcm2835_spidev
       *target , bool is_tx );

like, five arguments, one int coming back at you. she's lowkey high-maintenance but she delivers 💖

🫶 ARGUMENTS 🫶

  • ctlr — the SPI host controller. the whole venue, the big boss energy 👑
  • tfr — the SPI transfer. literally the thing being transferred, the moment, the event 🌟
  • bs — the BCM2835 SPI controller. yes there's also ctlr, don't come for me, they're different, iykyk 💀
  • target — the BCM2835 SPI target. the specific one we're talking to 🎯
  • is_tx — a bool that decides whether we submit the DMA descriptor for the TX sglist or the RX sglist. pick a lane bestie, it's one or the other 🙈

🔥 DESCRIPTION 🔥

so what she actually does: she prepares and submits a DMA descriptor for the TX or RX sglist of tfr. that's the whole vibe. not me explaining it in one sentence and then just vibing ✨

returns 0 on success, or a negative error number if things went sideways 😭 (kernel code, so negative numbers = bad news, always).

🦋 SEE ALSO 🦋

the kernel file ./drivers/spi/spi-bcm2835.c and honestly the whole friend group:

go read them. all of them. it's called self-care 💅

and that's the page!! brought to you by ./drivers/spi, dated October 2026, filed under bcm2835_spi_prepare_sg(9) — ily, go write some DMA descriptors responsibly 🫶🎀🌸

📦 where this page comes from