[PATCH v10 0/4] Nuvoton WPCM450 clock and reset driver

[Jonathan Neuschäfer]

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.

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/20230428190226.1304326-1-j.neuschaefer@gmx.net/
- 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/20220508194333.2170161-1-j.neuschaefer@gmx.net/
- 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/20220429172030.398011-1-j.neuschaefer@gmx.net/
- various small improvements

v1:
- https://lore.kernel.org/lkml/20220422183012.444674-1-j.neuschaefer@gmx.net/


Jonathan Neuschäfer (4):
  dt-bindings: clock: Add Nuvoton WPCM450 clock/reset controller
  ARM: dts: wpcm450: Remove clock-output-names from reference clock node
  clk: wpcm450: Add Nuvoton WPCM450 clock/reset controller driver
  ARM: dts: wpcm450: Switch clocks to clock controller

 .../bindings/clock/nuvoton,wpcm450-clk.yaml   |  65 +++
 .../arm/boot/dts/nuvoton/nuvoton-wpcm450.dtsi |  23 +-
 drivers/clk/Makefile                          |   2 +-
 drivers/clk/nuvoton/Kconfig                   |  10 +-
 drivers/clk/nuvoton/Makefile                  |   1 +
 drivers/clk/nuvoton/clk-wpcm450.c             | 372 ++++++++++++++++++
 .../dt-bindings/clock/nuvoton,wpcm450-clk.h   |  67 ++++
 7 files changed, 525 insertions(+), 15 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/clock/nuvoton,wpcm450-clk.yaml
 create mode 100644 drivers/clk/nuvoton/clk-wpcm450.c
 create mode 100644 include/dt-bindings/clock/nuvoton,wpcm450-clk.h

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2.43.0