[PATCH 1/2] SPI: control CS via standard GPIO operations instead of SPI-HW

[Martin Sperl]

> 
> On 04.03.2015, at 18:01, Marc Kleine-Budde <mkl at pengutronix.de> wrote:
> 
> You might want to use gpio_is_valid() instead of open coding it.
Under ideal circumstances spi_set_cs() would be GPL exported and then
I would not have to duplicate the code.

And there it is implemented like this, so my code includes it.

I just have kept the patch simple - in the long-run we should move that
route I assume and fix the code there to use gpio_is_valid().

Martin