From: Alexander Sverdlin <alexander.sverdlin@siemens.com>

Newer TI SoCs from K3 family (AM64x and newer) provide a detailed reset
cause information in RST_SRC register in the reset module within memory
mapped control registers. To make this information available in user space:

- provide the DT bindings for the reset module
- add the rest module to the device trees of the corresponding SoCs
- conditionally add custom SYSFS attribute group (if particular SoC
  supports it) with "reset_reason" attribute providing the textual
  form of the reset cause as documented in AM62x Processors Technical
  Reference Manual.

The location for the newly provided information was inspired by
drivers/soc/tegra/pmc.c.

The series has been tested on AM623 (relevant DT is k3-am62-wakeup.dtsi).
Interestingly, K3 can have multiple bits asserted, for instance in case of
WDT-triggered reset:

$ cat /sys/bus/soc/devices/soc0/reset_reason
Reset Caused by MCU ESM Error
Reset Caused by Main ESM Error

Alexander Sverdlin (3):
  dt-bindings: soc/reset: ti: add binding for k3 platforms reset module
  arm64: dts: ti: k3-*: Add am64x and newer reset module
  soc: ti: k3-socinfo: Provide reset reason information

 .../bindings/reset/ti,am64-rst.yaml           | 39 ++++++++
 .../soc/ti/ti,j721e-system-controller.yaml    | 11 +++
 arch/arm64/boot/dts/ti/k3-am62-wakeup.dtsi    |  5 ++
 arch/arm64/boot/dts/ti/k3-am62a-wakeup.dtsi   |  5 ++
 arch/arm64/boot/dts/ti/k3-am64-main.dtsi      |  5 ++
 drivers/soc/ti/k3-socinfo.c                   | 88 +++++++++++++++++++
 6 files changed, 153 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/reset/ti,am64-rst.yaml

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2.52.0