spi: bcm2835aux: add bcm2835 auxiliary spi device driver

The bcm2835 has 2 auxiliary spi bus masters spi1 and spi2.

This implements the driver to enable these devices.

The driver does not implement native chip-selects but uses
the aribtrary GPIO-chip-selects provided by the spi-chipselect.

Note that this driver relies on the fact that
the clock is implemented by the clk-bcm2835-aux driver,
which enables/disables the HW block when requesting/releasing
the clock.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 4887f31..26b8605 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -88,6 +88,17 @@
 	  is for the regular SPI controller. Slave mode operation is not also
 	  not supported.
 
+config SPI_BCM2835AUX
+	tristate "BCM2835 SPI auxiliary controller"
+	depends on ARCH_BCM2835 || COMPILE_TEST
+	depends on GPIOLIB
+	help
+	  This selects a driver for the Broadcom BCM2835 SPI aux master.
+
+	  The BCM2835 contains two types of SPI master controller; the
+	  "universal SPI master", and the regular SPI controller.
+	  This driver is for the universal/auxiliary SPI controller.
+
 config SPI_BFIN5XX
 	tristate "SPI controller driver for ADI Blackfin5xx"
 	depends on BLACKFIN && !BF60x