[PATCH v6 0/6] exynos-acpm: add DVFS protocol and clock driver

[Tudor Ambarus <tudor.ambarus@linaro.org>]

Dependencies description:
All patches should go through the Samsung SoC tree.
The acpm-clk driver (#4) depends on the ACPM DVFS ops (#2).
If the clock subsystem needs to merge the new clock driver, it will
need an immutable tag with the 2 patches.

The following DT patches depend on the bindings from #1:
https://lore.kernel.org/linux-samsung-soc/20250924-acpm-dvfs-dt-v4-0-3106d49e03f5@linaro.org/

The Alive CLock and Power Manager (ACPM) firmware exposes clocks that
are variable and index based. These clocks don't provide an entire range
of values between the limits but only discrete points within the range.
The firmware also manages the voltage scaling appropriately with the
clock scaling. Make the ACPM node a clock provider.

Add support for the ACPM DVFS protocol. It translates clock frequency
requests to messages that can be interpreted by the ACPM firmware.
Add an ACPM clock driver to model the clocks exposed by the ACPM firmware.

Thanks,
ta

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
---
Changes in v6:
- acpm-clk: s/b0/bo, (big ocean)
- acpm-dvfs: drop dbg_val arg from get_rate(). It's unused upstream and
  we'll probably choose to introduce a dedicated debug API if needed.
- MAINTAINERS: add ACPM clock bindings and driver (new patch)
- Link to v5: https://lore.kernel.org/r/20250924-acpm-clk-v5-0-4cca1fadd00d@linaro.org

Changes in v5:
- acpm-clk: address Stephen's comments:
  - drop of.h unused include, add devres/devres.h and container_of.h
    to avoid implicit includes.
  - r/acpm_clk_ops_init/acpm_clk_register.
  - remove period from error messages, drop comma after sentinel in
    platform_device_id.
- collect Peter's R-b and T-b tags.
- Link to v4: https://lore.kernel.org/r/20250908-acpm-clk-v4-0-633350c0c0b1@linaro.org

Changes in v4:
- clk-acpm:
  - remove GS101_ACPM_CLK_ID type handling. Dead code, it should be
    introduced with next devices.
  - remove runtime check on clock IDs. Instead add a comment about the
    assumptions the code is making: the clock IDs start from zero, are
    sequential and do not have gaps. Slight changes based on this
    assumption: s/hws[id]/hws[i], remove the inclusion of
    dt-bindings/clock/google,gs101-acpm.h and the use of the clock IDs.
    The clocks are defined solely by name in the driver.
- move firmware patches close to each other, in between the bindings and
  the clock driver
- update the description of dependencies in the cover letter.
- Link to v3: https://lore.kernel.org/r/20250903-acpm-clk-v3-0-65ecd42d88c7@linaro.org

Changes in v3:
- dt-bindings:
  - move clock bindings to a new bindings header
  - update commit's subject, s/add #clock-cells/add ACPM clocks.
    It also suggests that the bindings are added.
  - prepend "GS101_" on clocks binding name. The bindings name are the
    same for GS201 and the acpm-clk driver will likely include both.
  - collect Rob's R-b
- clk-acpm:
  - move clock definitions here instead of keeping them into the
    ACPM protocol driver
  - use platform_driver.id_table to differentiate device type
  - fix Kconfig dependency, || (COMPILE_TEST && !EXYNOS_ACPM_PROTOCOL)
  - update commit subject, s/dev/pdev
- exynos-acpm:
  - move clock definitions to clk-acpm
  - use devm-action to unregister clk-acpm platform device
- Link to v2: https://lore.kernel.org/r/20250827-acpm-clk-v2-0-de5c86b49b64@linaro.org

Changes in v2:
- dt-bindings: clocks are not longer a child of ACPM protocol. Instead
  make Alive Clock and Power Manager (ACPM) node a clock provider.
  Update commit message.
- firmware: exynos-acpm: register by hand the ACPM clocks dev (new
  patch)
- firmware: exynos-acpm: use defines intead of enum
- acpm-clk:
  - switch to determine_rate
  - drop __init, __refdata, __initconst, this is a module, we need those
    methods and data, after boot as well.
  - fix the assumption that the clocks are defined by ID in ascending order.
    There's still an assumption that the clk_id < nr_clks, but this is
    now covered by a sanity check in the clock driver.
- arm64: defconfig: enable Exynos ACPM clocks (add patch together with
  this patch set) 
- Link to v1: https://lore.kernel.org/r/20250819-acpm-clk-v1-0-6bbd97474671@linaro.org

---
Tudor Ambarus (6):
      dt-bindings: firmware: google,gs101-acpm-ipc: add ACPM clocks
      firmware: exynos-acpm: add DVFS protocol
      firmware: exynos-acpm: register ACPM clocks pdev
      clk: samsung: add Exynos ACPM clock driver
      arm64: defconfig: enable Exynos ACPM clocks
      MAINTAINERS: add ACPM clock bindings and driver

 .../bindings/firmware/google,gs101-acpm-ipc.yaml   |  11 ++
 MAINTAINERS                                        |   3 +-
 arch/arm64/configs/defconfig                       |   1 +
 drivers/clk/samsung/Kconfig                        |  10 ++
 drivers/clk/samsung/Makefile                       |   1 +
 drivers/clk/samsung/clk-acpm.c                     | 185 +++++++++++++++++++++
 drivers/firmware/samsung/Makefile                  |   4 +-
 drivers/firmware/samsung/exynos-acpm-dvfs.c        |  80 +++++++++
 drivers/firmware/samsung/exynos-acpm-dvfs.h        |  21 +++
 drivers/firmware/samsung/exynos-acpm.c             |  26 +++
 include/dt-bindings/clock/google,gs101-acpm.h      |  26 +++
 .../linux/firmware/samsung/exynos-acpm-protocol.h  |  10 ++
 12 files changed, 376 insertions(+), 2 deletions(-)
---
base-commit: 5472d60c129f75282d94ae5ad072ee6dfb7c7246
change-id: 20250819-acpm-clk-28d2a78e0307

Best regards,
-- 
Tudor Ambarus <tudor.ambarus@linaro.org>