[PATCH v7 0/6] Add clock controller support for SpacemiT K1

[Haylen Chu <heylenay@4d2.org>]

The clock tree of SpacemiT K1 is managed by several independent
multifunction devices, some of them are

- Application Power Manage Unit, APMU
- Main Power Manage Unit, MPMU
- APB Bus Clock Unit, APBC
- APB Spare, APBS

These four devices provide hardware bits for three purposes: power
management, reset signals and clocks. Not every device is capable of all
the three functionalities,

- APMU, MPMU: power, reset, clock
- APBC: clock, reset
- APBS: clock (PLL clocks)

This series adds support for clock hardwares in these four regions,
which covers most peripherals except DDR and the realtime processor.

Tested on BananaPi-F3 board. With some out-of-tree drivers, I've
successfully brought up I2C, RTC, MMC and ethernet controllers.

It has been a very long time since I sent v1 of the series, thanks for
everyone making suggestions and keeping track. I'm looking forward for
furthermore reviews, or getting it finally merged.

Changed from v6
- Update copyright date
- Collect reviewed-by tags
- k1-pll binding
  - replace tabs with space in binding header
- driver
  - remove the file accidentally added in v6
  - remove undesired rates from PLL2 configuration entries
  - update comment for PLL{1,2} rates
  - misc style changes
  - remove CLK_IS_CRITICAL from uart0 clocks and cpu_c1_hi_clk
- TWSI8 support
  - Add a comment to describe the quirk
- defconfig change
  - improve the commit message
- Link to v6: https://lore.kernel.org/all/20250401172434.6774-1-heylenay@4d2.org/

Changed from v5
- Correct "Spacemit" to "SpacemiT" in commit messages and code
- Always use space instead of TAB in comments for consistency
- dt-bindings
  - Rename binding header to "spacemit,k1-syscon.h"
  - apply review tags
- driver code
  - remove "default" properties from Kconfig
  - misc style and naming improvements
  - make ccu_read() directly return the read value, drop ccu_poll() and
    reorder the arguments to ccu_{read,update} macros
  - drop ccu_common.reg_swcr2
  - clock tree for K1
    - define PLL3 with the correct offset of SWCR3 register
    - synchronize PLL configuration entries with the vendor kernel
    - reformat clocks definitions
    - explain why PLLs require the MPMU syscon to function
    - log a message when failing to register a clock
    - simplify clock registration with ARRAY_SIZE()
  - ddn
    - correctly handle masks which doesn't start from BIT(0) when
      calculating the best rate
    - improve precision of frequency calculation
    - derive _{den,num}_shift from corresponding masks with __ffs()
  - mix
    - match the full mask of gate in ccu_gate_is_enabled()
    - add a note about "frequency change" bit and simplify FC-triggering
      logic
    - drop unnecessary local variables and initialization from clock
      operations
    - round to the closest rate in ccu_mix_calc_best_rate()
    - change names of all mix subtypes to follow the order of mux ->
      factor/div -> gate -> fc
    - drop unused _flags argument from CCU_GATE_FACTOR_DEFINE()
  - pll
    - ensure PLLs are initialized to a known state
    - drop extra check in ccu_pll_enable()
    - round to the closest rate in ccu_pll_round_rate()
- TWSI8 support
  - Split cleanly from the main driver commit
- devicetree
  - drop extra "*-cells" and "ranges" properties
- Enable SpacemiT K1 CCU in RISC-V defconfig
- Link to v5: https://lore.kernel.org/all/20250306175750.22480-2-heylenay@4d2.org/

Changed from v4
- bindings:
  - Drop CLK_*_NUM macros from binding headers
  - Rename spacemit,k1-ccu.yaml to spacemit,k1-pll.yaml, change to
    describe only the PLL in APBS region
  - k1-syscon.yaml
    - drop spacemit,k1-syscon-apbs, it should be the PLL device
    - drop child nodes
    - describe the syscons as clock, reset and power-domain controllers
    - drop "syscon" from the compatible list, as these syscons aren't
      compatible with the generic one
- driver:
  - misc style fixes and naming improvements
  - drop unused fields from data structures
  - drop unused clock types: CCU_DDN_GATE
  - ddn type:
    - improve the comments
    - dynamically calculate appropriate rates
    - hardcode the x2 factor
  - mix type
    - drop val_{disable,enable} for gate subtype
    - drop unncessary polling when enabling a gate
    - encode subtypes directly in struct ccu_mix
    - generate clock names from identifiers of the data structure
    - rename CCU_DIV2_FC_MUX_GATE_DEFINE to CCU_DIV_SPLIT_FC_MUX_GATE
  - pll type:
    - correctly claim the parent clock
    - make rate tables const
    - drop SWCR2-related fields
    - combine fields of registers as a whole instead of working with
      each field
  - clock tree for k1:
    - removed duplicated offsets
    - drop the placeholder 1:1 factor, pll1_d7_351p8
    - workaround the quirk of TWSI8 clocks
    - fix the definition of ripc_clk, wdt_bus_clk, dpu_bit_clk and
      timers_*_clk
    - drop structure spacemit_ccu_priv and spacemit_ccu_data
    - rework clock registration
    - split the PCIe clocks correctly (there're three distinct clocks
      for each PCIe port)
- devicetree:
  - adapt the new binding
- Link to v4: https://lore.kernel.org/all/20250103215636.19967-2-heylenay@4d2.org/

Changed from v3
- spacemit,k1-ccu binding
  - allow spacemit,mpmu property only for controllers requiring it
    (spacemit,k1-ccu-apbs)
- spacemit,k1-syscon binding
  - drop unnecessary *-cells properties
  - drop unrelated nodes in the example
- driver
  - remove unnecessary divisions during rate calucalation in ccu_ddn.c
  - use independent clk_ops for different ddn/mix variants, drop
    reg_type field in struct ccu_common
  - make the register containing frequency change bit a sperate field in
    ccu_common
  - unify DIV_MFC_MUX_GATE and DIV_FC_MUX_GATE
  - implement a correct determine_rate() for mix type
  - avoid reparenting in set_rate() for mix type
  - fix build failure when SPACEMIT_CCU and SPACEMIT_CCU_K1 are
    configured differently
- use "osc" instead of "osc_32k" in clock input names
- misc style fixes
- Link to v3: https://lore.kernel.org/all/20241126143125.9980-2-heylenay@4d2.org/

Changed from v2
- dt-binding fixes
  - drop clocks marked as deprecated by the vendor (CLK_JPF_4KAFBC and
    CLK_JPF_2KAFBC)
  - add binding of missing bus clocks
  - change input clocks to use frequency-aware and more precise names
  - mark input clocks and their names as required
  - move the example to the (parent) syscon node and complete it
  - misc style fixes
- misc improvements in code
- drop unnecessary spinlock in the driver
- implement missing bus clocks
- Link to v2: https://lore.kernel.org/all/SEYPR01MB4221829A2CD4D4C1704BABD7D7602@SEYPR01MB4221.apcprd01.prod.exchangelabs.com/

Changed from v1
- add SoC prefix (k1)
- relicense dt-binding header
- misc fixes and style improvements for dt-binding
- document spacemit,k1-syscon
- implement all APBS, MPMU, APBC and APMU clocks
- code cleanup
- Link to v1: https://lore.kernel.org/all/SEYPR01MB4221B3178F5233EAB5149E41D7902@SEYPR01MB4221.apcprd01.prod.exchangelabs.com/

Haylen Chu (6):
  dt-bindings: soc: spacemit: Add spacemit,k1-syscon
  dt-bindings: clock: spacemit: Add spacemit,k1-pll
  clk: spacemit: Add clock support for SpacemiT K1 SoC
  clk: spacemit: k1: Add TWSI8 bus and function clocks
  riscv: dts: spacemit: Add clock tree for SpacemiT K1
  riscv: defconfig: spacemit: enable clock controller driver for
    SpacemiT K1

 .../bindings/clock/spacemit,k1-pll.yaml       |   50 +
 .../soc/spacemit/spacemit,k1-syscon.yaml      |   80 ++
 arch/riscv/boot/dts/spacemit/k1.dtsi          |   75 ++
 arch/riscv/configs/defconfig                  |    2 +
 drivers/clk/Kconfig                           |    1 +
 drivers/clk/Makefile                          |    1 +
 drivers/clk/spacemit/Kconfig                  |   18 +
 drivers/clk/spacemit/Makefile                 |    5 +
 drivers/clk/spacemit/ccu-k1.c                 | 1164 +++++++++++++++++
 drivers/clk/spacemit/ccu_common.h             |   48 +
 drivers/clk/spacemit/ccu_ddn.c                |   83 ++
 drivers/clk/spacemit/ccu_ddn.h                |   47 +
 drivers/clk/spacemit/ccu_mix.c                |  268 ++++
 drivers/clk/spacemit/ccu_mix.h                |  218 +++
 drivers/clk/spacemit/ccu_pll.c                |  157 +++
 drivers/clk/spacemit/ccu_pll.h                |   86 ++
 .../dt-bindings/clock/spacemit,k1-syscon.h    |  247 ++++
 17 files changed, 2550 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/spacemit,k1-pll.yaml
 create mode 100644 Documentation/devicetree/bindings/soc/spacemit/spacemit,k1-syscon.yaml
 create mode 100644 drivers/clk/spacemit/Kconfig
 create mode 100644 drivers/clk/spacemit/Makefile
 create mode 100644 drivers/clk/spacemit/ccu-k1.c
 create mode 100644 drivers/clk/spacemit/ccu_common.h
 create mode 100644 drivers/clk/spacemit/ccu_ddn.c
 create mode 100644 drivers/clk/spacemit/ccu_ddn.h
 create mode 100644 drivers/clk/spacemit/ccu_mix.c
 create mode 100644 drivers/clk/spacemit/ccu_mix.h
 create mode 100644 drivers/clk/spacemit/ccu_pll.c
 create mode 100644 drivers/clk/spacemit/ccu_pll.h
 create mode 100644 include/dt-bindings/clock/spacemit,k1-syscon.h

-- 
2.49.0


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