inv_icm45600...te_watermark(9)

💅 inv_icm45600_buffer_update_watermark — Kernel API Manual 🎀

okay bestie, so this is a kernel API page (yes, the ones from the Kernel API Manual, iykyk) and honestly? it's giving "one function, but the math is doing the most." ✨

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🌸 NAME 🌸

inv_icm45600_buffer_update_watermark — update that FIFO watermark threshold, periodt 💖

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✨ SYNOPSIS ✨

int inv_icm45600_buffer_update_watermark (struct inv_icm45600_state *st
);

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🫶 ARGUMENTS 🫶

• st — the driver internal state. literally the whole personality of the driver in one struct 💅

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🦋 DESCRIPTION 🦋

so the FIFO watermark threshold gets computed from the required watermark values that were set for the gyro and accel sensors — that's the vibe. 🎀

and like, watermark is all about acceptable data latency (how much lag you're willing to tolerate, lowkey), so you'd think "just pick the smallest setting between the 2, done" 🙈 — but no cap, it's not as simple as choosing the smallest watermark value. because latency depends on watermark AND ODR. so it's a whole little journey:

1. compute the gyro latency and the accel latency, then choose the smallest value. ⭐
2. adapt that chosen latency so it's a multiple of both the gyro one and the accel one. otherwise it's possible that you don't meet a requirement — like, fr fr, check this: with gyro 100Hz wm 4 and accel 100Hz with wm 6, choosing the value of 4 will not meet the accel latency requirement because 6 is not a multiple of 4. you need to use the value 2. 😭 (see? the math said no)
3. since all the periods are multiples of each other, the watermark is computed by dividing this computed latency by the smallest period — which corresponds to the FIFO frequency. 🔥

bestie be careful: skip step 2 and you can straight up miss a requirement. it's giving "shortcut = regret." 💀

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👑 RETURN 👑

0 on success, a negative error code otherwise. 🌈

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🧚 SEE ALSO 🧚

Kernel file ./drivers/iio/imu/inv_icm45600/inv_icm45600_buffer.c — go be nosy, it's iconic 💜

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that's the whole page bestie, ily, go update some watermarks 🍓✨ — with love from ./drivers/iio/imu/inv_icm45600, dated October 2026, signing off 🫶🦋