cs_amp_get_...bration_data(9)

✨ NAME ✨

okay bestie, welcome to the Kernel API Manual 💖 — not me hyping up a kernel function, but this is the page for cs_amp_get_...bration_data(9), and the actual function is cs_amp_get_efi_calibration_data. Its whole job? get an entry from calibration data in EFI. lowkey iconic, highkey useful. 🎀

🌸 SYNOPSIS 🌸

here's the signature, copy it exactly and don't let autocorrect touch it:

int cs_amp_get_efi_calibration_data (struct device *dev , u64 target_uid
, int amp_index , struct cirrus_amp_cal_data *out_data );

🦋 ARGUMENTS 🦋

these are the four args, no cap:

• dev — struct device of the caller. that's your device bestie. 💅
• target_uid — UID to match, or 0 to ignore UID matching.
• amp_index — entry index to use, or -1 to prevent lookup by index.
• out_data — struct cirrus_amp_cal_data where the entry will be copied. it's the output spot. 🫶

🔥 DESCRIPTION 🔥

this function can perform 3 types of lookup, and yes we're listing all three because details are the moment:

1. (target_uid > 0, amp_index >= 0) — UID search with fallback to using the array index. Search the calibration data for a non-zero calTarget that matches target_uid, and if found return that entry. Else, if the entry at [amp_index] has calTarget == 0, return that entry. Else fail.
2. (target_uid > 0, amp_index < 0) — UID search only. Search the calibration data for a non-zero calTarget that matches target_uid, and if found return that entry. Else fail.
3. (target_uid == 0, amp_index >= 0) — Array index fetch only. Return the entry at [amp_index].

An array lookup will be skipped if amp_index exceeds the number of entries in the calibration array, and in this case the return will be -ENOENT. An out-of-range amp_index does not prevent matching by target_uid — it has the same effect as passing amp_index < 0. 🫶

If the EFI data is too short to be a valid entry, or the entry count in the EFI data overflows the actual length of the data, this function returns -EOVERFLOW. 💀

⭐ RETURN ⭐

the return values are giving clean error-code realness:

• 0 if the entry was found
• -ENOENT if no entry was found
• -EOVERFLOW if the EFI file is corrupt
• else other error value

🌈 SEE ALSO 🌈

Kernel file ./sound/soc/codecs/cs-amp-lib.c — plus these besties:

• cs_amp_write_cal_coeffs(9)
• cs_amp_read_cal_coeffs(9)
• cs_amp_write_ambient_temp(9)
• cs_amp_set_efi_calibration_data(9)
• cs_amp_get_vendor_spkid(9)
• cs_amp_devm_get_vendor_specific_variant_id(9)
• cs_amp_create_debugfs(9)

mwah 💋 — signed off from ./sound/soc/codecs, dated October 2026, for the page cs_amp_get_...bration_data(9). periodt. 💖