[coreboot] [PATCH] use Kconfig for both options on Lippert boards

Jens Rottmann JRottmann at LiPPERTEmbedded.de
Tue Aug 31 20:07:29 CEST 2010

Peter wrote:
> Maybe make that one option per port instead, with choices "RS232" and
> "RS485", since the code allows it very easily.

I had considered this but decided against it. I'd guess that, like,
96.3% of all users will want both ports speak the same protocol. In fact
most will want RS232, RS485 is already very rare, but mixed operation
must be really, really exotic.

It is simply not feasible to make _everything_ configurable, one has to
draw a line somewhere. That's why I didn't add an option to turn off the
Spread Spectrum in SMC_CONFIG, either. Before I would consider this,
there are lots of settings which are _much_ more likely to get changed

Like disabling devices completely to save power, I/O resources and IRQs.
Or moving PCI INT A-D or legacy devices to a different IRQ line. (Our
boards still feature ISA, provided by an IT8888 PCI-to-ISA bridge.)
These are the things our customers request all the time. And even though
our standard BIOSes (Insyde and Phoenix) have all this in the normal
BIOS Setup, we _still_ keep providing many customers with variants of
our standard BIOSes - like one making sure that a certain bit pattern is
written as early as possible to the LPT data port (3rd assembler
instruction actually) and is kept until OS has finished booting. (The
customer in question is (ab)using the LPT data pins as GPIOs to control
pieces of hardware in a satellite - embedded customers are ... umm ...
different.) There is no way you can make _everything_ user-configurable.

I agree that easy access to all knobs would be great, but for that you'd
 have to start with devicetree.cb, and allow a flag added to each
setting saying "do autogenerate Kconfig entry for this option".

> Maybe also make an (expert?) option to disable the LED?

It's a red LED for free use of the customer's application - like "new
mail has arrived" or "satellite ran out of fuel".  ;-)  I think most
customers rather change the LED at runtime than by reconfiguring
coreboot. The '1' I write to it makes sure it's initally off.


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