On 9 May 2012 14:50, Heiko Stübner [off-list ref] wrote:

Am Mittwoch, 9. Mai 2012, 00:04:51 schrieb Thomas Abraham:

quoted

The set_level callback in the controller data, which is used to configure
the slave select line, cannot be supported when migrating the driver to
device tree based discovery. Since all the platforms currently use gpio
as the slave select line, this callback can be removed from the
controller data and replaced with call to gpio_set_value in the driver.

I was quite fond of the set_level callback. On one of the machines I'm working
on there is some sort of multiplexer (TI-sn74cbtlv3257) sitting between the
controller and spi devices to provide support for more than one device.
So I was doing the switch to the correct device in the set_level callback,
which worked quite well.

I suppose you should still be able to do that defining virtual gpios backed
by appropriate physical mux'ing of lines ?

-jassi