[v2,0/5] reset: introduce generic reset-simple controller

Message

Inochi Amaoto Feb. 26, 2025, 11:42 p.m. UTC

Many SoC have a simple reset controller with toggling bit to perform
assert/deassert. It is annoyed to add device id to the reset-simple
driver for each device when coming a new SoC.

This patch series introduce a generic binding to collect devices
match the following requirement:
- There is a single, contiguous range of 32-bit registers.
- All bits in each register directly control a reset line.
   - There are no self-deasserting resets.
   - There are no timing requirements.
   - The bits are exclusively resets, nothing else.
- All bits behave the same, so all reset bits are either
  active-high or all are active-low.
- The bits can be read back, but the read status may
  be active-low independently from the writes.

If the device follows the requirement, it can set the compatiable
and reuse the provided "reset-simple" as base compatiable without
changing the reset-simple driver with unnecessary new device id.

Add a generic reset-simple controller, and migrate the Sophgo
SG2042 reset controller as an example.

Change from v1:
- https://lore.kernel.org/all/[e-mail]/
1. fix title to mark it introduce new generic device for
   reset-simple driver
2. add "active-low" property support for the generic reset-simple
   device.
3. patch 1: update the binding description to illustrate the
   suitable scenarios to use this binding.

Inochi Amaoto (5):
  dt-bindings: reset: add generic bit reset controller
  reset: simple: Add active-low property support.
  reset: simple: add support generic reset-simple device
  dt-bindings: reset: simple: migrate sophgo sg2042 reset controller
  riscv: dts: sg2042: Adapt reset generator for new binding

 .../bindings/reset/reset-simple.yaml          | 66 +++++++++++++++++++
 .../bindings/reset/sophgo,sg2042-reset.yaml   | 35 ----------
 arch/riscv/boot/dts/sophgo/sg2042.dtsi        |  3 +-
 drivers/reset/reset-simple.c                  |  7 ++
 4 files changed, 75 insertions(+), 36 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/reset/reset-simple.yaml
 delete mode 100644 Documentation/devicetree/bindings/reset/sophgo,sg2042-reset.yaml

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2.48.1