Add support for the Thermal Management Unit (TMU) on the Google GS101 SoC. The GS101 TMU implementation utilizes a hybrid architecture where management is shared between the kernel and the Alive Clock and Power Manager (ACPM) firmware.
Dependencies ============ - firmware patches 2, 3: required by the thermal driver (patch 4). - bindings (patch 1): required for DTS validation. - thermal driver patch 4: required by defconfig (patch 7) - logical dependency. Given the thermal driver is a new addition, I suggest everything to go through the Samsung SoC tree, with ACKs from the Thermal maintainers. If the Thermal maintainers prefer to take the bindings and the thermal driver patches via their tree we'll need: - an immutable branch containing the firmware patches (2 and 3) from the Samsung SoC tree to serve as a base for the thermal driver. - an immutable branch containing the bindings and the thermal driver from the thermal tree to serve as a base for the dts and defconfig. Architecture Overview ===================== The hardware supports two parallel control paths. For this implementation, responsibilities are split as follows: 1. Kernel Responsibility: - maintain direct memory-mapped access to the interrupt pending (INTPEND) registers to identify thermal events. - map physical hardware interrupts to logical thermal zones. - coordinate functional operations through the ACPM IPC protocol. 2. Firmware Responsibility (ACPM): - handle sensor initialization and calibration. - manage thermal thresholds and hysteresis configuration. - perform temperature acquisition and expose data via IPC. Sensor Mapping (One-to-Many) ============================ The SoC contains multiple physical temperature sensors, but the ACPM firmware abstracts these into logical groups (Clusters) for reporting: - ACPM Sensor 0 (Big Cluster): Aggregates physical sensors 0, 6, 7, 8, 9. - ACPM Sensor 1 (Mid Cluster): Aggregates physical sensors 4, 5. - ACPM Sensor 2 (Little Cluster): Aggregates physical sensors 1, 2. The driver maps physical interrupt bits back to these logical parents. When an interrupt fires, the driver checks the bitmask in the INTPEND registers and updates the corresponding logical thermal zone. Signed-off-by: Tudor Ambarus <[email protected]> --- Changes in v2: - architecture: switch from a syscon/MFD approach to a thermal-sensor node with a phandle to the ACPM interface - bindings: address Krzysztof's feedback, drop redundencies, interrupts description. - firmware: introduce devm_acpm_get_by_phandle() to standardize IPC handle acquisition. - thermal driver: drop compatible's data and use the static data from the driver directly. - defconfig, make EXYNOS_ACPM_THERMAL a module - Link to v1: https://lore.kernel.org/r/[email protected] --- Tudor Ambarus (7): dt-bindings: thermal: Add Google GS101 TMU firmware: samsung: acpm: Add TMU protocol support firmware: samsung: acpm: Add devm_acpm_get_by_phandle helper thermal: samsung: Add support for GS101 TMU MAINTAINERS: Add entry for Samsung Exynos ACPM thermal driver arm64: dts: exynos: gs101: Add thermal management unit arm64: defconfig: enable Exynos ACPM thermal support .../bindings/thermal/google,gs101-tmu-top.yaml | 67 +++ MAINTAINERS | 8 + arch/arm64/boot/dts/exynos/google/gs101-tmu.dtsi | 209 +++++++ arch/arm64/boot/dts/exynos/google/gs101.dtsi | 18 + arch/arm64/configs/defconfig | 1 + drivers/firmware/samsung/Makefile | 1 + drivers/firmware/samsung/exynos-acpm-tmu.c | 212 +++++++ drivers/firmware/samsung/exynos-acpm-tmu.h | 33 ++ drivers/firmware/samsung/exynos-acpm.c | 35 ++ drivers/thermal/samsung/Kconfig | 16 + drivers/thermal/samsung/Makefile | 2 + drivers/thermal/samsung/acpm-tmu.c | 643 +++++++++++++++++++++ .../linux/firmware/samsung/exynos-acpm-protocol.h | 30 + 13 files changed, 1275 insertions(+) --- base-commit: e2211f5d980086dd9fbdab3bcd86b715e12cae13 change-id: 20260113-acpm-tmu-27e21f0e2c3b Best regards, -- Tudor Ambarus <[email protected]>
