get_valid_routes(9)

💅 get_valid_routes(9) — the Kernel API Manual page, but make it make sense 🎀

okay so bestie, welcome to the glow-up of get_valid_routes(9) from the Kernel API Manual ✨ this is the little helper that rings up your low-level driver's own get_valid_routes function and asks it to either hand back a count of valid routes to userspace or copy the whole list of all valid device routes into a userspace buffer 🦋 two jobs, one function, main character energy fr fr 💖

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✨ SYNOPSIS ✨

int get_valid_routes (struct comedi_device *dev , unsigned int *data );

that's it, that's the whole vibe check 👑 no cap 🌸

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🫶 ARGUMENTS 🫶

• dev — a comedi device pointer 💜 your ticket to the device, basically.
• data — the data from the user insn call. Now listen, this one's the whole personality, so let's break it down 🧚:
  • the length of data must be >= 2 — not optional, lowkey non-negotiable 😭
  • data[0] must contain the INSN_DEVICE_CONFIG config_id — that's the whole point of showing up 💅
  • data[1] (input) contains the number of pairs that memory is allotted for from the user. so it's pairs, not routes-singular, keep up bestie 💀
  • if the user specifies '0' there, then only the number of pairs available is returned — no copying, just the count, like a little peek 🔥
  • data[1] (output) returns either the number of pairs available (if none were requested) or the number of pairs that actually got copied back to the user ⭐
  • data[2::2] returns each (source, destination) pair 🦋 so it's the pair list, strutting out two at a time 🌈

ngl the data[1] slot is doing double duty as input and output and honestly it's giving versatility, we stan 🎀 — just remember which direction the info is flowing in at any given moment, bestie 🙈

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🌸 RETURN 🌸

• -EINVAL — if the low-level driver does not allocate and return routes as expected. iykyk, the driver didn't slay 😭
• 0 — returned otherwise. success, periodt 💖

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👑 SEE ALSO 👑

these are the girlies in the same friend group, go say hi ✨

• Kernel file ./drivers/comedi/comedi_fops.c
• struct comedi_file(9)
• comedi_dev_put(9)
• comedi_dev_get_from_minor(9)
• comedi_is_subdevice_running(9)
• comedi_get_is_subdevice_running(9)
• comedi_put_is_subdevice_running(9)
• comedi_set_spriv_auto_free(9)
• comedi_alloc_spriv(9)
• comedi_event(9)

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and that's the page, bestie 🫶 this little icon comes from ./drivers/comedi, dated October 2026, and it's filed under get_valid_routes(9) forever 💜 mwah 💋