Re: [PATCH v2 02/12] mfd: stm32-fmc2: add STM32 FMC2 controller driver

[Lee Jones]

On Wed, 15 Apr 2020, Christophe Kerello wrote:

> The driver adds the support for the STMicroelectronics FMC2 controller
> found on STM32MP SOCs.
> 
> The FMC2 functional block makes the interface with: synchronous and
> asynchronous static memories (such as PSNOR, PSRAM or other
> memory-mapped peripherals) and NAND flash memories.
> 
> Signed-off-by: Christophe Kerello <christophe.kerello@xxxxxx>
> ---
> Changes in v2:
>  - remove ops from stm32_fmc2 structure
>  - add 2 APIs to manage FMC2 enable/disable
>  - add 2 APIs to manage FMC2 NWAIT shared signal
> 
>  drivers/mfd/Kconfig            |  12 +++
>  drivers/mfd/Makefile           |   1 +
>  drivers/mfd/stm32-fmc2.c       | 136 +++++++++++++++++++++++++
>  include/linux/mfd/stm32-fmc2.h | 225 +++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 374 insertions(+)
>  create mode 100644 drivers/mfd/stm32-fmc2.c
>  create mode 100644 include/linux/mfd/stm32-fmc2.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 2b20329..5260582 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1922,6 +1922,18 @@ config MFD_ROHM_BD71828
>  	  Also included is a Coulomb counter, a real-time clock (RTC), and
>  	  a 32.768 kHz clock gate.
>  
> +config MFD_STM32_FMC2
> +	tristate "Support for FMC2 controllers on STM32MP SoCs"
> +	depends on MACH_STM32MP157 || COMPILE_TEST
> +	select MFD_CORE
> +	select REGMAP
> +	select REGMAP_MMIO
> +	help
> +	  Select this option to enable STM32 FMC2 driver used for FMC2 External
> +	  Bus Interface controller and FMC2 NAND flash controller. This driver
> +	  provides core support for the STM32 FMC2 controllers, in order to use
> +	  the actual functionality of the device other drivers must be enabled.

Not sure how many times I have to say this before people stop
attempting to pass these kinds of relationships off as MFDs:

A memory device and its bus is not an MFD.  In a similar vain to the
thousands of USB, I2C, SPI, PCI and the like devices that aren't MFDs
either.

Please find another way to associate your device with its bus.

-- 
Lee Jones [æçæ]
Linaro Services Technical Lead
Linaro.org â Open source software for ARM SoCs
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