spi: kirkwood_spi: Add support for multiple chip-selects on MVEBU

Currently only chip-select 0 is supported by the kirkwood SPI driver.
The Armada XP / 38x SoCs also use this driver and support multiple chip
selects. This patch adds support for multiple CS on MVEBU.

The register definitions are restructured a bit with this patch. Grouping
them to the corresponding registers.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Jagan Teki <jteki@openedev.com>
diff --git a/arch/arm/include/asm/arch-mvebu/spi.h b/arch/arm/include/asm/arch-mvebu/spi.h
index 526fea6..78869a2 100644
--- a/arch/arm/include/asm/arch-mvebu/spi.h
+++ b/arch/arm/include/asm/arch-mvebu/spi.h
@@ -35,13 +35,15 @@
 #define SCK_MPP10	(1 << 1)
 #define MISO_MPP11	(1 << 2)
 
+/* Control Register */
+#define KWSPI_CSN_ACT		(1 << 0) /* Activates serial memory interface */
+#define KWSPI_SMEMRDY		(1 << 1) /* SerMem Data xfer ready */
+#define KWSPI_CS_SHIFT		2	/* chip select shift */
+#define KWSPI_CS_MASK		0x7	/* chip select mask */
+
+/* Configuration Register */
 #define KWSPI_CLKPRESCL_MASK	0x1f
 #define KWSPI_CLKPRESCL_MIN	0x12
-#define KWSPI_CSN_ACT		1 /* Activates serial memory interface */
-#define KWSPI_SMEMRDY		(1 << 1) /* SerMem Data xfer ready */
-#define KWSPI_IRQUNMASK		1 /* unmask SPI interrupt */
-#define KWSPI_IRQMASK		0 /* mask SPI interrupt */
-#define KWSPI_SMEMRDIRQ		1 /* SerMem data xfer ready irq */
 #define KWSPI_XFERLEN_1BYTE	0
 #define KWSPI_XFERLEN_2BYTE	(1 << 5)
 #define KWSPI_XFERLEN_MASK	(1 << 5)
@@ -50,6 +52,11 @@
 #define KWSPI_ADRLEN_3BYTE	(2 << 8)
 #define KWSPI_ADRLEN_4BYTE	(3 << 8)
 #define KWSPI_ADRLEN_MASK	(3 << 8)
+
+#define KWSPI_IRQUNMASK		1 /* unmask SPI interrupt */
+#define KWSPI_IRQMASK		0 /* mask SPI interrupt */
+#define KWSPI_SMEMRDIRQ		1 /* SerMem data xfer ready irq */
+
 #define KWSPI_TIMEOUT		10000
 
 #endif /* __KW_SPI_H__ */