[RFC 2/4] mfd: add Gateworks System Controller core driver

[Randy Dunlap]

On 02/27/2018 05:21 PM, Tim Harvey wrote:
> The Gateworks System Controller (GSC) is an I2C slave controller
> implemented with an MSP430 micro-controller whose firmware embeds the
> following features:
>  - I/O expander (16 GPIO's) using PCA955x protocol
>  - Real Time Clock using DS1672 protocol
>  - User EEPROM using AT24 protocol
>  - HWMON using custom protocol
>  - Interrupt controller with tamper detect, user pushbotton
>  - Watchdog controller capable of full board power-cycle
>  - Power Control capable of full board power-cycle
> 
> see http://trac.gateworks.com/wiki/gsc for more details
> 
> Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> ---
>  drivers/mfd/Kconfig     |  10 ++
>  drivers/mfd/Makefile    |   1 +
>  drivers/mfd/gsc.c       | 330 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/gsc.h |  79 ++++++++++++
>  4 files changed, 420 insertions(+)
>  create mode 100644 drivers/mfd/gsc.c
>  create mode 100644 include/linux/mfd/gsc.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 1d20a80..16dd486 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -341,6 +341,16 @@ config MFD_EXYNOS_LPASS
>  	  Select this option to enable support for Samsung Exynos Low Power
>  	  Audio Subsystem.
>  
> +config MFD_GSC
> +	tristate "Gateworks System Controller"
> +	depends on (I2C && OF) || COMPILE_TEST

Do both I2C and OF have stubs so that a driver will build when they are
both disabled?  I.e., only COMPILE_TEST is enabled?


> +	select MFD_CORE
> +	select REGMAP_I2C
> +	select REGMAP_IRQ
> +	help
> +	  Enable support for the Gateworks System Controller found
> +	  on Gateworks Single Board Computers.
> +
>  config MFD_MC13XXX
>  	tristate
>  	depends on (SPI_MASTER || I2C)
thanks,
-- 
~Randy