Re: [PATCH 4/8] platform: arm64: qcom-hamoa-ec: Add fan RPM query and LUT calibration

[Konrad Dybcio]

On 7/28/26 7:44 PM, Anvesh Jain P wrote:
> Add the EC command definitions and handler functions for querying fan
> RPM and programming per-fan LUTs (lookup tables mapping SoC
> temperature to target RPM), and introduce a raw i2c_transfer()-based
> transport for the two commands, since their variable-length,
> sub-command-addressed payloads don't fit the smbus block-data model
> used by the existing commands.
> 
> Fan LUT geometry and temperature breakpoints vary by board, so encode
> them in per-compatible qcom_ec_lut_config data selected via
> device_get_match_data(). Add configs for the Hamoa CRD, Hamoa/Purwa
> IOT EVK, and Glymur CRD ECs; IOT EVK boards share the Hamoa LUT
> geometry but are bring-up platforms without a calibrated fan curve,
> so skip_lut_set suppresses the LUT-set command on those boards.

So are we expecting every single laptop/device that utilizes a
compatible EC to require modifications to the driver here?

> Since the LUT values depend on each fan's maximum RPM, which varies
> per board assembly, calibrate it at runtime: drive the fan to full
> PWM, wait for it to spin up, and read back the achieved RPM via the
> new query command. Run calibration in a work item at probe time and
> after EC reset recovery, and make it abortable via a completion so
> suspend can cut it short. Track calibration completion state so the
> LUT is programmed once calibration finishes and again on every
> subsequent power-supply-driven profile switch.

I don't want my laptop to become a jetplane on every bootup. I
doubt anyone does.

Konrad