On Tue, Mar 13, 2012 at 10:58:20AM +0800, Axel Lin wrote:
> Unused GPIO is marked as -1, we need to check if one of the gpio is set to 0
> here because gpio_is_valid considers 0 as a valid gpio.

This will break existing boards, we need to manage the transfer more
gracefully and complain if we're using a GPIO 0.  Though I'm not sure
it's worth bothering, I hope no modern gpiolib implementation will do
this.