spi: Migrate CONFIG_MXS_SPI to Kconfig

Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
diff --git a/configs/bg0900_defconfig b/configs/bg0900_defconfig
index e097f1c..20c8feb 100644
--- a/configs/bg0900_defconfig
+++ b/configs/bg0900_defconfig
@@ -32,4 +32,5 @@
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_BAR=y
 CONFIG_SPI_FLASH_STMICRO=y
+CONFIG_MXS_SPI=y
 CONFIG_OF_LIBFDT=y
diff --git a/configs/m28evk_defconfig b/configs/m28evk_defconfig
index be0c681..373519d 100644
--- a/configs/m28evk_defconfig
+++ b/configs/m28evk_defconfig
@@ -46,6 +46,7 @@
 CONFIG_NAND_MXS=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_STMICRO=y
+CONFIG_MXS_SPI=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
diff --git a/configs/mx28evk_auart_console_defconfig b/configs/mx28evk_auart_console_defconfig
index a3590bb..e9f6ff4 100644
--- a/configs/mx28evk_auart_console_defconfig
+++ b/configs/mx28evk_auart_console_defconfig
@@ -41,6 +41,7 @@
 CONFIG_NAND_MXS=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SST=y
+CONFIG_MXS_SPI=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
diff --git a/configs/mx28evk_defconfig b/configs/mx28evk_defconfig
index 5d661ee..b57bee6 100644
--- a/configs/mx28evk_defconfig
+++ b/configs/mx28evk_defconfig
@@ -41,6 +41,7 @@
 CONFIG_NAND_MXS=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SST=y
+CONFIG_MXS_SPI=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
diff --git a/configs/mx28evk_nand_defconfig b/configs/mx28evk_nand_defconfig
index 3b9962f..8d8bafa 100644
--- a/configs/mx28evk_nand_defconfig
+++ b/configs/mx28evk_nand_defconfig
@@ -40,6 +40,7 @@
 CONFIG_NAND_MXS=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SST=y
+CONFIG_MXS_SPI=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
diff --git a/configs/mx28evk_spi_defconfig b/configs/mx28evk_spi_defconfig
index fee7f21..8959035 100644
--- a/configs/mx28evk_spi_defconfig
+++ b/configs/mx28evk_spi_defconfig
@@ -40,6 +40,7 @@
 CONFIG_NAND_MXS=y
 CONFIG_SPI_FLASH=y
 CONFIG_SPI_FLASH_SST=y
+CONFIG_MXS_SPI=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_STORAGE=y
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index a1f9373..686105c 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -263,6 +263,12 @@
 	help
 	  Enable support for SPI on MPC8XX
 
+config MXS_SPI
+	bool "MXS SPI Driver"
+	help
+	  Enable the MXS SPI controller driver. This driver can be used
+	  on the i.MX23 and i.MX28 SoCs.
+
 config OMAP3_SPI
 	bool "McSPI driver for OMAP"
 	help
diff --git a/include/configs/mxs.h b/include/configs/mxs.h
index 0bc3d49..31877b8 100644
--- a/include/configs/mxs.h
+++ b/include/configs/mxs.h
@@ -147,7 +147,6 @@
 /* SPI */
 #ifdef CONFIG_CMD_SPI
 #define CONFIG_HARD_SPI
-#define CONFIG_MXS_SPI
 #define CONFIG_SPI_HALF_DUPLEX
 #endif
 
diff --git a/scripts/config_whitelist.txt b/scripts/config_whitelist.txt
index c428712..275c20b 100644
--- a/scripts/config_whitelist.txt
+++ b/scripts/config_whitelist.txt
@@ -1437,7 +1437,6 @@
 CONFIG_MXS_AUART_BASE
 CONFIG_MXS_GPIO
 CONFIG_MXS_OCOTP
-CONFIG_MXS_SPI
 CONFIG_MX_CYCLIC
 CONFIG_MY_OPTION
 CONFIG_NANDFLASH_SIZE