Release v1.4.0 — MPU cpufreq DVFS to 1.2 GHz (3.4×) · petronijus/nexusQ-reloaded

[1.4.0] - 2026-06-26

MPU CPU frequency scaling — on-demand up to 1.2 GHz (3.4× the old floor). 🚀
The OMAP4460 was pinned at its 350 MHz boot OPP; it now scales across
350 / 700 / 920 / 1200 MHz under the ondemand governor. Built up in small,
hardware-validated stages, each cross-checked against this unit's
reverse-engineered stock kernel:
- VDD_MPU is handed from the TWL6030 VCORE1 SMPS to the external TPS62361
  regulator over the PRM Voltage-Controller SR-i2c — the same hand-over stock does.
- A thin "VC-bridge" cpu-supply regulator lets cpufreq-dt scale the rail
  through the OMAP voltage layer (VP force-update), at the stock-measured nominal
  voltages (1025 / 1203 / 1317 / 1380 mV).
- At the 1.2 GHz OPP, Forward Body Bias is engaged on VDD_MPU via the on-chip
  ABB LDO — required for stable 1.2 GHz operation.
- Thermal throttling: at the 100 °C trip the CPU cooling drops the frequency
  and ramps it back as it cools, so sustained full load stays safe.
USB serial debug console. The USB gadget is now an ACM serial console
(/dev/ttyACM0 on the host, with a steelhead login: prompt) that survives
reboots and leaves fastboot untouched.

The USB gadget no longer exposes a host-side network interface — it was swapped
from the RNDIS network gadget to the serial console above. Use the on-board
ethernet / WiFi for networking.

On-board LAN9500A USB-Ethernet is down — a regression from 1.3.0. 🌐 The
Ethernet that 1.3.0 fixed no longer enumerates on these cpufreq builds: the
LAN9500A fails to connect (the EHCI port's PORTSC connect-status stays 0). It
is a boot-timing side-effect of the voltage/cpufreq changes, which tipped the
formerly-marginal connect timing into consistent failure. WiFi works in the
meantime; a fix (a settle delay in the ethernet bring-up, or reordering the
voltage init) is tracked for 1.4.1.

Full Changelog: v1.3.0...v1.4.0