spi: cadence: Fix 3-to-8 mux mode

In 3-to-8 mux mode for the CS pins we need to set the PERI_SEL bit in the
control register. Currently the driver never sets this bit even when
configured for 3-to-8 mux mode. This patch adds code which sets the bit
during device initialization when necessary.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Harini Katakam <harinik@xilinx.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-cadence.c

@@ -47,6 +47,7 @@
 #define CDNS_SPI_CR_CPHA_MASK		0x00000004 /* Clock Phase Control */
 #define CDNS_SPI_CR_CPOL_MASK		0x00000002 /* Clock Polarity Control */
 #define CDNS_SPI_CR_SSCTRL_MASK		0x00003C00 /* Slave Select Mask */
+#define CDNS_SPI_CR_PERI_SEL_MASK	0x00000200 /* Peripheral Select Decode */
 #define CDNS_SPI_CR_BAUD_DIV_MASK	0x00000038 /* Baud Rate Divisor Mask */
 #define CDNS_SPI_CR_MSTREN_MASK		0x00000001 /* Master Enable Mask */
 #define CDNS_SPI_CR_MANSTRTEN_MASK	0x00008000 /* Manual TX Enable Mask */
@@ -148,6 +149,11 @@ static inline void cdns_spi_write(struct cdns_spi *xspi, u32 offset, u32 val)
  */
 static void cdns_spi_init_hw(struct cdns_spi *xspi)
 {
+	u32 ctrl_reg = CDNS_SPI_CR_DEFAULT_MASK;
+
+	if (xspi->is_decoded_cs)
+		ctrl_reg |= CDNS_SPI_CR_PERI_SEL_MASK;
+
 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
 		       CDNS_SPI_ER_DISABLE_MASK);
 	cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET,
@@ -160,8 +166,7 @@ static void cdns_spi_init_hw(struct cdns_spi *xspi)
 
 	cdns_spi_write(xspi, CDNS_SPI_ISR_OFFSET,
 		       CDNS_SPI_IXR_ALL_MASK);
-	cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET,
-		       CDNS_SPI_CR_DEFAULT_MASK);
+	cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg);
 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
 		       CDNS_SPI_ER_ENABLE_MASK);
 }