[PATCH v6 0/2] riscv: pwm: sophgo: add pwm support for CV1800

[Jingbao Qiu]

The Sophgo CV1800 chip provides a set of four independent
PWM channel outputs.
This series adds PWM controller support for Sophgo cv1800.

Changes since v5:
- delete the OE function because we plan to use the counter subsystem
  instead of capture, so there is no need to reuse this code.
- fix set polarity reverse error.

v5: https://lore.kernel.org/all/20240314100131.323540-1-qiujingbao.dlmu@xxxxxxxxx/

Changes since v4:
- drop filename
- fix macro
- optimize cv1800_pwm_set_polarity()
- optimize cv1800_pwm_set_oe()
- add comment for cv1800_pwm_set_oe()
- use ticks replace tem
- fix duty_cycle larger than period_val
- use devm_clk_rate_exclusive_get() replace
  clk_rate_exclusive_get()
- map linux polarity to register polarity 

v4: https://lore.kernel.org/all/20240304085933.1246964-1-qiujingbao.dlmu@xxxxxxxxx/

datasheet Link: https://github.com/milkv-duo/duo-files/blob/main/duo/datasheet/CV1800B-CV1801B-Preliminary-Datasheet-full-en.pdf
page 614

Changes since v3:
- use macro instead of npwm number
- add support for polarity feature
- add support for Output-Enable/OE feature

v3: https://lore.kernel.org/all/20240223082014.109385-1-qiujingbao.dlmu@xxxxxxxxx/

Changes since v2:
- use 0x08 instead of macro
- split if statements based on conditions
- in order to round up, first calculate the
  number of high-level cycles, then subtract
  it from the PERIOD to obtain the number of HLPERIOD
- use new pwmchip_alloc() API instead of old style

v2: https://lore.kernel.org/all/20240212121729.1086718-1-qiujingbao.dlmu@xxxxxxxxx/

Changes since v1:
- drop full stop from subject
- re-order maintainers and description
- pass checkpatch.pl --strict
- fix naming errors
- add "Limitations" section
- use a driver specific prefix for all defines
- using bool instead u32 in cv1800_pwm_enable
- check and set state->polarity
- use mul_u64_u64_div_u64
- use clk_rate_exclusive_get(), balance with clk_rate_exclusive_put()
- using macro definitions instead of shift operations
- remove shift operation on 0
- use priv replace cv_pwm
- hardcode npwm
- set atomic to true
- remove MODULE_ALIAS

v1: https://lore.kernel.org/all/20240207055856.672184-1-qiujingbao.dlmu@xxxxxxxxx/

Jingbao Qiu (2):
  dt-bindings: pwm: sophgo: add pwm for Sophgo CV1800 series SoC
  pwm: sophgo: add pwm support for Sophgo CV1800 SoC

 .../bindings/pwm/sophgo,cv1800-pwm.yaml       |  45 +++
 drivers/pwm/Kconfig                           |  10 +
 drivers/pwm/Makefile                          |   1 +
 drivers/pwm/pwm-cv1800.c                      | 296 ++++++++++++++++++
 4 files changed, 352 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/sophgo,cv1800-pwm.yaml
 create mode 100644 drivers/pwm/pwm-cv1800.c

-- 
2.25.1