[U-Boot] [PATCH 1/2] ARM Conditionally compile board LED functions

Tom Tom.Rix at windriver.com
Thu Nov 5 21:47:29 CET 2009


Wolfgang Denk wrote:
> Dear Tom Rix,
> 
> In message <1257292804-10612-2-git-send-email-Tom.Rix at windriver.com> you wrote:
>> The ARM board LED functions are defined as weak.
>> They add a size overhead if they are not used.
>>
>> Now they are only defined if CONFIG_STATUS_LED is also defined.
>>
>> The arm920t and arm926ejs _start function calls these LED functions
>>
>> 	bl	coloured_LED_init
>> 	bl	red_LED_on
>>
>> In general, what happens is they call into the weak
>> stubs.  Only if the cpu/board provides an overriding
>> function do these calls cause anything meaningful to
>> happen.
>>
>> Now this noop case is removed and these LED functions are excuted
>> only when CONFIG_STATUS_LED is defined
> 
> I don't get it. We use "weak" to avoid #ifdef's, and you insert new
> #ifdef's?   That seems to be the wrong approach to me.
> 

The arguments for using weak are getting weak :P

Using weak is less relevant with the #ifdef's
The benefit now is that boards that use the led functions do
not have to define all of them.

I am open to ideas on how to kill weak off completely.

Has a general led driver layer ever been proposed ?
Something to convert status led for a mixture of #defines and weak
symbols to something that had a register function and some
file_ops ?

Tom

Tom

> Best regards,
> 
> Wolfgang Denk
> 



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