Re: [PATCH v3 0/2] Add support for Microchip's pwm fpga core

[Conor.Dooley]

On 17/06/2022 12:44, Conor Dooley wrote:
> Hey Uwe,
> Got a ~v2~ v3 for you...
> I added some comments explaining the calculations and a documentation link
> so hopefully things are a bit easier to follow.
> 
> Code wise, I went through and sorted out a bunch of issues that cycling
> through the different periods/duties threw up. Along the way I found
> some other problems - especially with the longer periods which I have
> fixed. I also added a write to the sync register in the apply function,
> which will resolve to a NOP for channels without "shadow registers".
> 
> Other than that, I managed to ditch the mchp_core_pwm_registers struct
> entirely but had to add a short delay before reading back the registers
> in order to compute the duty.
> 
> Thanks,
> Conor.

*sigh* yet again I forgot to mention the potential maintainers conflict
with spi-next..

> 
> Changes from v2:
> - fix percieved idempotency and rounding issues when shadow registers were
>    enabled
> - use do_div() for divide of u64 tmp in apply_period()
> 
> Changes from v1:
> - account for edge "quirk" while inverted
> - block changing enabled channels' period
> - document the hardware/driver limitations
> - rearrange get_state() more logically
> - fix cast sizes in get_state()
> - fix remove() and probe error paths
> - delete mchp_core_pwm_registers
> - simplify .apply() logic
> - don't warn in calculate_base()
> - fix period calculation
> - fix duty cycle calculation
> - add COREPWM prefix to defines
> - add a documentation link
> 
> Conor Dooley (2):
>    pwm: add microchip soft ip corePWM driver
>    MAINTAINERS: add pwm to PolarFire SoC entry
> 
>   MAINTAINERS                      |   1 +
>   drivers/pwm/Kconfig              |  10 +
>   drivers/pwm/Makefile             |   1 +
>   drivers/pwm/pwm-microchip-core.c | 325 +++++++++++++++++++++++++++++++
>   4 files changed, 337 insertions(+)
>   create mode 100644 drivers/pwm/pwm-microchip-core.c
> 
> 
> base-commit: 61114e734ccb804bc12561ab4020745e02c468c2