spi/tegra114: add spi driver

Add SPI driver for NVIDIA's Tegra114 SPI controller. This controller
is different than the older SoCs SPI controller in internal design as
well as register interface.

This driver supports the:
- non DMA based transfer for smaller transfer i.e. less than FIFO depth.
- APB DMA based transfer for larger transfer i.e. more than FIFO depth.
- Clock gating through runtime PM callbacks.
- registration through DT only.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 2946ab4..864d87f 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -415,6 +415,14 @@
 	help
 	  SPI driver for Freescale MXS devices.
 
+config SPI_TEGRA114
+	tristate "NVIDIA Tegra114 SPI Controller"
+	depends on ARCH_TEGRA && TEGRA20_APB_DMA
+	help
+	  SPI driver for NVIDIA Tegra114 SPI Controller interface. This controller
+	  is different than the older SoCs SPI controller and also register interface
+	  get changed with this controller.
+
 config SPI_TEGRA20_SFLASH
 	tristate "Nvidia Tegra20 Serial flash Controller"
 	depends on ARCH_TEGRA