Re: [PATCH v12 0/6] Driver for at91 usart in spi mode

Lee Jones
2018-09-11T09:34:03Z

On Tue, 04 Sep 2018, Radu Pirea wrote:
> Radu Pirea (6):
> MAINTAINERS: add at91 usart mfd driver
> dt-bindings: add binding for atmel-usart in SPI mode
> mfd: at91-usart: added mfd driver for usart
> MAINTAINERS: add at91 usart spi driver
> spi: at91-usart: add driver for at91-usart as spi
> tty/serial: atmel: change the driver to work under at91-usart mfd
>
> .../bindings/{serial => mfd}/atmel-usart.txt | 25 +-
> MAINTAINERS | 16 +
> drivers/mfd/Kconfig | 9 +
> drivers/mfd/Makefile | 1 +
> drivers/mfd/at91-usart.c | 71 +++
> drivers/spi/Kconfig | 8 +
> drivers/spi/Makefile | 1 +
> drivers/spi/spi-at91-usart.c | 432 ++++++++++++++++++
> drivers/tty/serial/Kconfig | 1 +
> drivers/tty/serial/atmel_serial.c | 42 +-
> include/dt-bindings/mfd/at91-usart.h | 17 +
> 11 files changed, 606 insertions(+), 17 deletions(-)
> rename Documentation/devicetree/bindings/{serial => mfd}/atmel-usart.txt (76%)
> create mode 100644 drivers/mfd/at91-usart.c
> create mode 100644 drivers/spi/spi-at91-usart.c
> create mode 100644 include/dt-bindings/mfd/at91-usart.h

Seeing as this patch-set has caused some issues this morning, I took
the liberty to peruse back into its history to figure out where things
started to go wrong. I also re-reviewed the MFD driver - and I'm glad
I did!

My Acked-by has been attached to the MFD portion since v5, which is
why the code hasn't caught my eye before today. I reviewed the
relocation of the *binding document* (serial => mfd with no changes)
in v4 and nothing else. It appears as though you mistakenly added it
to the *MFD driver* instead. This explains my confusion in v10 when I
told you I'd already reviewed the binding document.

As I said, I have re-reviewed the MFD driver and I'm afraid to say
that I do not like what I see. Besides the missing header file and
the whitespace tabbing errors, I do not agree with the implementation.
Using MFD as a shim to hack around driver selection is not a valid
use-case.

What's stopping you from just using the compatible string directly to
select which driver you need to probe?

--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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