[RFC,0/6] qcom: Add an SoC PM driver for sc7180 using PM domains

Message

Stephen Boyd Jan. 8, 2025, 1:28 a.m. UTC

This series implements an SoC PM driver for Qualcomm's SC7180 SoC that
creates devices for the nodes that make up the soc node and attaches PM
domains to those devices before the devices are added to the platform
bus. The overall plan is to remove power management logic from various
platform drivers and consolidate it into this SoC PM driver using PM
domains. This series isn't there yet, as I haven't had the time to do
much beyond this starting part.

This is a followup to my presentation at OSSEU in 2024[1]. I'm sending
it out so that the early pieces can land while we work through the PM
domain parts which I worry is going to get annoying rather quickly.

TODO:
 * Populate more child devices and attach more pm domains to test out
   more stuff
 * Set power state of PM domains to match on/off state of resources like
   clks, regulators, etc.
 * Investigate setting runtime PM state of devices before they're added
   to platform bus
 * Remove PM code from drivers using the platform_data non-NULL trick
 * Make multiple domains? Perhaps clk domain, regulator domain,
   interconnect domain, etc?
 * Provide a way for runtime active devices out of boot to be powered
   down when a driver isn't attached

[1] https://osseu2024.sched.com/event/1ej38/the-case-for-an-soc-power-management-driver-stephen-boyd-google

Stephen Boyd (6):
  bus: Extract simple-bus into self-contained driver
  dt-bindings: bus: Add qcom,soc-sc7180 SoC
  bus: Add basic sc7180 bus driver
  of: Extract alloc/add functions from of_platform_device_create_pdata()
  bus: qcom-sc7180: Attach pm domain to watchdog device
  arm64: dts: qcom: sc7180: Add SoC specific compatible to soc node

 .../bindings/bus/qcom,soc-sc7180.yaml         |  76 ++++++++
 arch/arm64/boot/dts/qcom/sc7180.dtsi          |   2 +-
 drivers/bus/Kconfig                           |  26 +++
 drivers/bus/Makefile                          |   6 +
 drivers/bus/qcom/Kconfig                      |  16 ++
 drivers/bus/qcom/Makefile                     |   3 +
 drivers/bus/qcom/qcom-sc7180.c                | 173 ++++++++++++++++++
 drivers/bus/simple-bus.c                      |  79 ++++++++
 drivers/bus/simple-pm-bus.c                   |   2 +
 drivers/of/platform.c                         | 130 +++++++++++--
 include/linux/of_platform.h                   |  14 ++
 11 files changed, 511 insertions(+), 16 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/bus/qcom,soc-sc7180.yaml
 create mode 100644 drivers/bus/qcom/Kconfig
 create mode 100644 drivers/bus/qcom/Makefile
 create mode 100644 drivers/bus/qcom/qcom-sc7180.c
 create mode 100644 drivers/bus/simple-bus.c


base-commit: 3c48780d48df029cf9d5f42b8971663e6fb975ae