Re: [PATCH v1 1/2] i2c: designware: Make master module optional

[Jarkko Nikula <jarkko.nikula@linux.intel.com>]

On 3/23/20 12:04 PM, Andy Shevchenko wrote:
> In some cases we know that the controller will be always used in slave mode and
> master is just a bulk. In order to drop that, introduce a separate configuration
> parameter for master mode. Default it to core to avoid regressions.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>   drivers/i2c/busses/Kconfig                  | 10 ++++++++++
>   drivers/i2c/busses/Makefile                 |  5 ++++-
>   drivers/i2c/busses/i2c-designware-core.h    | 19 ++++++++++++++++++-
>   drivers/i2c/busses/i2c-designware-master.c  |  4 ++--
>   drivers/i2c/busses/i2c-designware-pcidrv.c  |  2 +-
>   drivers/i2c/busses/i2c-designware-platdrv.c |  6 +-----
>   6 files changed, 36 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 2ddca08f8a76..1df238ff8dd0 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -527,6 +527,16 @@ config I2C_DAVINCI
>   config I2C_DESIGNWARE_CORE
>   	tristate
>   
> +config I2C_DESIGNWARE_MASTER
> +	bool "Synopsys DesignWare Master"
> +	default I2C_DESIGNWARE_CORE
> +	help
> +	  If you say yes to this option, support will be included for the
> +	  Synopsys DesignWare I2C master adapter.
> +
> +	  This is not a standalone module, this module compiles together with
> +	  i2c-designware-core.
> +

I think we should go to a opposite direction - reduce the number of 
I2C_DESIGNWARE_ config options rather than add new ones. We already have 
5 config options for it.

Size of i2c-designware-core.ko is around 12 kB with all master, slave 
and Baytrail semaphore code built in so I don't think it justifies the 
added config complexity. I think distributions will have anyway all of 
those options set.

Having those code in separate modules and load only when needed might 
make sense as that would save a few kB of RAM.

-- 
Jarkko