[U-Boot] [PATCH v4 08/10] mmc: make UHS and HS200 optional

[Jean-Jacques Hiblot <jjhiblot@ti.com>]

On 02/12/2017 04:29, Simon Glass wrote:
> Hi Jean-Jacques,
>
> On 29 November 2017 at 07:29, Jean-Jacques Hiblot <jjhiblot@ti.com> wrote:
>> Supporting USH and HS200 increases the code size as it brings in IO voltage
>> control, tuning and fatter data structures.
>> Use Kconfig configuration to select which of those features should be
>> built in.
>>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
>> ---
>>   drivers/mmc/Kconfig      | 46 +++++++++++++++++++++++++++++++++++
>>   drivers/mmc/mmc-uclass.c |  4 +++
>>   drivers/mmc/mmc.c        | 63 +++++++++++++++++++++++++++++++++++++++++++++++-
>>   include/mmc.h            | 27 ++++++++++++++++++---
>>   4 files changed, 135 insertions(+), 5 deletions(-)
> A few things:
>
> - Can these default to on? I think going fast is best, and reducing
> functionality can be an option

This is conservative decision. The patches are less likely to break 
untested platforms if this is not enabled if only because of the 
increased footprint.
Most platforms won't benefit from it at first because the host driver 
has to implement a few more callbacks to support those modes.
We can always default to 'y' later when more host support this.
> - Can you use if (IS_ENABLED) instead of #if within functions?
I wasn't sure about the ability of the compiler to always throw away 
unused code this way. I'll give it a try.
>
> Regards,
> Simon
>