[U-Boot] [U-Boot,v2,04/19] gpio: Add a simple GPIO API for SPL

[Philipp Tomsich]

> In space-constrained environments or before driver model is available, it
> is sometimes necessary to set GPIO values. Add an SPL API for this, to
> allow early board code to change GPIOs. The caller must provide the
> register address, so that the drivers can be fairly generic.
> 
> This API can be implemented by GPIO drivers, behind a suitable guard,
> like #ifdef CONFIG_SPL_BUILD.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
> 
> Changes in v2: None
> 
>  include/spl_gpio.h | 62 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 62 insertions(+)
>  create mode 100644 include/spl_gpio.h
> 

Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>