Add row to "Decisions baked into the code" table explaining the DATA line
control design: all DATA assert/release operations in the worker and ATN ISR
go through iec_data_*_sync() under iec_data_lock to serialize the GPFSEL0
read-modify-write across CPUs. The release wrapper refuses to release while
ATN is asserted, preventing the ready-for-data release from erasing the ISR's
presence acknowledge — the bug that caused intermittently missed
LISTEN/UNLISTEN commands. Init/exit/self-test keep raw unconditional helpers.
Generated by Clanker 🤖
Adopt the confirmed-working reference's pin assignment so the module runs
on that proven wiring: DATA=BCM2 (pin 3), CLK=BCM3 (pin 5), ATN=BCM4
(pin 7). RESET is kept and relocated to BCM17 (pin 11), the pin freed by
moving CLK. All five GPIOs stay in bank 0, so the direct-register hot
path and ATN IRQ are unchanged -- only the IEC_GPIO_* defines, the
device-tree overlay, and the docs/self-test move.
DATA/CLK now sit on the ARM I2C pins (GPIO2/3) with the SoC's fixed
~1.8k pull-ups; keep dtparam=i2c_arm off. The bare-board self-test
expectation changes from 0x15 to 0x0b accordingly.
Generated by Clanker
The IEC bit loop sampled GPIO with a single register read, so a glitch
on a level-shifted 5V<->3.3V bus could corrupt a bit with no chance to
retry (the loop runs with IRQs off). Add a stable-read filter that only
believes a level change after it holds IEC_DEBOUNCE_US (now 5 us); the
fast path is a single read so tight CLK polls stay cheap. Used across
the receive hot path; the ATN ISR and self-test keep raw reads.
Generated by Clanker
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Introduce a conditional `trusted=yes` setting for the Raspberry Pi
repository in the Dockerfile when `DEBIAN_SUITE=trixie`. This bypasses
SHA1 signature rejection by trixie's apt system using Sequoia. Ensure
that bookworm maintains full signature verification. Updated
documentation to explain the trixie-specific caveat.
Introduce `DEBIAN_SUITE` as a configurable argument in the Dockerfile, build
script, and CI workflow to align kernel builds with the target Raspberry Pi
OS release. Updated documentation to clarify the relationship between
suite versions and kernel compatibility.
Expand the documentation to include details on GPIO descriptor
lookup using chip label and hardware offset, replacing the deprecated
global GPIO number approach. Added instructions for verifying the module's
version magic to ensure compatibility with the running kernel. These
updates aim to prevent common initialization and deployment errors.
