>Please do not top-post.

Sorry, I'll keep in mind.

>>     I have change u-boot-fslc from branch "patches-2014.01" to
>> "patches-2014.07" this week.
>>
>>     I notice that gpio_get_value( ) always return 0, no matter I set the bit
>> 0 or 1.
>
>You need to pass the SION flag into a GPIO if you want to read the
>value of a GPIO output.

you're right, I'm sorry not searching community forum first, after your hint I found you have answered here:
https://community.freescale.com/thread/316873

thanks.

Wally