[U-Boot] [PATCH 0/2] arm nomadik: gpio and i2c

[Heiko Schocher]

Hello Wolfgang,

Wolfgang Denk wrote:
> Dear Alessandro Rubini,
> 
> In message <cover.1247999841.git.rubini at unipv.it> you wrote:
>> To use soft_i2c I need to define some macros in the config file.
>> Instead of writing hard numbers there I called the gpio functions, but
>> the config file is inluded from asm sources as well.  I don't think my
>> approach is beautiful at all (both #ifndef __ASSEMBLY__ and #include
>> "../board/"), but I didn't find a better solution.
> 
> Agreed. It's a bit intricate to get this done, but I don't see a
> better way either.

Hmm.. maybe my previous patch is a better solution?

>> I would like to add a gpio command, and I've found no generic gpio
>> stuff.  Only one board (cm-bf527) has a gpio commands, but quite a few
>> have similar commands to set leds or other bits.  Is time ripe for a
>> generic gpio driver with board-specific limits and operations? Would
>> that be interesting for u-boot-next?  Should I process with a board-specific
>> gpio command by now?
> 
> Well, my opinion on that is a clear "yes, but..." :-)
> 
> Yes, some generic gpio framework would be nice - for example,  if  it
> would allow us to get rid of the 14 largely similar "led.c" files, to
> name just one.
> 
> On the other hand, the design of such a framework should be lean  and
> not  necessarily  try  to  cover 100% of all possible use cases - I'd
> rather have a small and beautiful solution that  covers  90%  of  the
> cases  and use board-specific exceptions where really needed, instead
> of a fat thing that solves each and every problem but costs 50 kB.

Agreed. So we need an gpio_core.c / .h which defines the following
functions (just a proposal):

typedef struct gpio_adapter {
	int	(*init_pin)(int pin);
	int	(*set)(int pin, value);
	int	(*get)(int pin);
	int	(*dir)(int pin, int direction);	
	int	(*level)(int pin, int level);
}

int gpio_init(gpio_adapter *adap);
int gpio_init_pin(pin);
	? maybe with setting a marker, that this pin is initialized,
	  so this can be checked in the above functions ... ?
int gpio_set(pin, value);
int gpio_get(pin);
int gpio_dir(pin, dir);
int gpio_level(pin, dir);

bye
Heiko