comedi_auto_config(9)

💅 comedi_auto_config(9)

okay so this is a page straight out of the Kernel API Manual, and it's literally the glow-up moment where a hardware device becomes a COMEDI device. bestie, it's giving matchmaker energy 🎀

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✨ NAME ✨

comedi_auto_config — Create a COMEDI device for a hardware device

🦋 SYNOPSIS 🦋

int comedi_auto_config (struct device *hardware_device , struct
       comedi_driver *driver , unsigned long context );

🌸 ARGUMENTS 🌸

• hardware_device — the hardware device. yes, that one. the actual physical-ish thing you're setting up 🫶
• driver — the COMEDI low-level driver for the hardware device. this is the one doing the actual work, no cap.
• context — driver context for the auto_attach handler. think of it as the little note you pass along so auto_attach knows what's up 💌

💖 DESCRIPTION 💖

So what happens is: it allocates a new COMEDI device for the hardware device, then calls the low-level driver's auto_attach handler to set up the hardware and allocate the COMEDI subdevices. iconic behaviour, honestly ✨

Then, once auto_attach returns successfully, some extra "post-configuration" setting up gets performed. but listen — if the auto_attach handler fails, the low-level driver's detach handler gets called as part of the clean-up. so it always tidies up after itself, we love a responsible main character 🧹

This is usually called from a wrapper function in a bus-specific COMEDI module, which in turn is usually called from a bus device probe function in the low-level driver. it's giving chain reaction, iykyk 🌈

Returns:

• 0 on success — slay 🎉
• -EINVAL if the parameters are invalid, or if the post-configuration determines the driver has set the COMEDI device up incorrectly
• -ENOMEM if it failed to allocate memory 😭
• -EBUSY if it ran out of COMEDI minor device numbers
• or some negative error number returned by the driver's auto_attach handler

ngl, that last one is just "whatever the driver says went wrong" — so don't be shocked if you get a number that isn't in this list 💀

🔥 SEE ALSO 🔥

Kernel file ./drivers/comedi/drivers.c

• comedi_set_hw_dev(9)
• comedi_alloc_devpriv(9)
• comedi_alloc_subdevices(9)
• comedi_alloc_subdev_readback(9)
• comedi_readback_insn_read(9)
• comedi_timeout(9)
• comedi_dio_insn_config(9)
• comedi_dio_update_state(9)
• comedi_bytes_per_scan_cmd(9)
• comedi_bytes_per_scan(9)
• comedi_nscans_left(9)
• comedi_nsamples_left(9)
• comedi_inc_scan_progress(9)
• comedi_handle_events(9)
• comedi_load_firmware(9)
• __comedi_check_request_region(9)
• comedi_check_request_region(9)
• comedi_legacy_detach(9)
• comedi_auto_unconfig(9)
• comedi_driver_register(9)
• comedi_driver_unregister(9)

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and that's the whole page, bestie 💅 this lil gem lives at ./drivers/comedi and it's dated October 2026, so go forth and auto-config, mwah 🍓👑