[v12,0/6] Nuvoton WPCM450 clock and reset driver

Message

Jonathan Neuschäfer May 2, 2024, 10:39 a.m. UTC

This series adds support for the clock and reset controller in the Nuvoton
WPCM450 SoC. This means that the clock rates for peripherals will be
calculated automatically based on the clock tree as it was preconfigured
by the bootloader.  The 24 MHz dummy clock, that is currently in the
devicetree, is no longer needed.  Somewhat unfortunately, this also
means that there is a breaking change once the devicetree starts relying
on the clock driver, but I find it acceptable in this case, because
WPCM450 is still at a somewhat early stage.

v12:
- Convert to platform driver, but use fixed-factor-clock for timer
  (a necessary workaround because npcm7xx-timer needs its clock earlier
  than a platform driver can provide it)
- Various driver improvements suggested or inspired by Stephen Boyd
- New patches:
  - clk: Introduce devm_clk_hw_register_divider_table_parent_data()
  - clk: provider: Address documentation pitfall in struct clk_parent_data

v11:
- Link: https://lore.kernel.org/r/[e-mail]
- Improved description in "ARM: dts: wpcm450: Remove clock-output-names
  from reference clock node"
- some minor format differences due to switching to B4

v10:
- A small tweak (using selected instead of extending an already-long
  default line) in Kconfig, for better robustness

v9:
- Various improvements to the driver
- No longer use global clock names (and the clock-output-names property)
  to refer to the reference clock, but instead rely on a phandle reference

v8:
- https://lore.kernel.org/lkml/[e-mail]/
- Use %pe throughout the driver

v7:
- Simplified the error handling, by largely removing resource
  deallocation, which:
  - was already incomplete
  - would only happen in a case when the system is in pretty bad state
    because the clock driver didn't initialize correctly (in other
    words, the clock driver isn't optional enough that complex error
    handling really pays off)

v6:
- Dropped all patches except the clock binding and the clock driver, because
  they have mostly been merged
- Minor correction to how RESET_SIMPLE is selected

v5:
- Dropped patch 2 (watchdog: npcm: Enable clock if provided), which
  was since merged upstream
- Added patch 2 (clocksource: timer-npcm7xx: Enable timer 1 clock before use) again,
  because I wasn't able to find it in linux-next
- Switched the driver to using struct clk_parent_data
- Rebased on 6.1-rc3

v4:
- Leave WDT clock running during after restart handler
- Fix reset controller initialization
- Dropped patch 2/7 (clocksource: timer-npcm7xx: Enable timer 1 clock before use),
  as it was applied by Daniel Lezcano

v3:
- https://lore.kernel.org/lkml/[e-mail]/
- Changed "refclk" string to "ref"
- Fixed some dead code in the driver
- Added clk_prepare_enable call to the watchdog restart handler
- Added a few review tags

v2:
- https://lore.kernel.org/lkml/[e-mail]/
- various small improvements

v1:
- https://lore.kernel.org/lkml/[e-mail]/

Signed-off-by: Jonathan Neuschäfer <[e-mail]>
---
---
Jonathan Neuschäfer (6):
      dt-bindings: clock: Add Nuvoton WPCM450 clock/reset controller
      clk: Introduce devm_clk_hw_register_divider_table_parent_data()
      clk: provider: Address documentation pitfall in struct clk_parent_data
      clk: wpcm450: Add Nuvoton WPCM450 clock/reset controller driver
      ARM: dts: wpcm450: Remove clock-output-names from reference clock node
      ARM: dts: wpcm450: Switch clocks to clock controller

 .../bindings/clock/nuvoton,wpcm450-clk.yaml        |  65 +++
 arch/arm/boot/dts/nuvoton/nuvoton-wpcm450.dtsi     |  33 +-
 drivers/clk/Makefile                               |   2 +-
 drivers/clk/nuvoton/Kconfig                        |  10 +-
 drivers/clk/nuvoton/Makefile                       |   1 +
 drivers/clk/nuvoton/clk-wpcm450.c                  | 455 +++++++++++++++++++++
 include/dt-bindings/clock/nuvoton,wpcm450-clk.h    |  67 +++
 include/linux/clk-provider.h                       |  26 +-
 8 files changed, 643 insertions(+), 16 deletions(-)
---
base-commit: 4cece764965020c22cff7665b18a012006359095
change-id: 20240330-wpcm-clk-222a37f59cfb

Best regards,
--
Jonathan Neuschäfer <[e-mail]>