spi/orion: Add SPI_CHPA and SPI_CPOL support to kirkwood driver.

Support these transfer modes from the SPI layer by setting
the appropriate register bits before doing the transfer.

This was tested on the Marvell kirkwood SOC that uses this driver.
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Rolf Manderscheid <rvm@obsidianresearch.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/spi/spi-orion.c

@@ -32,8 +32,12 @@
 #define ORION_SPI_DATA_IN_REG		0x0c
 #define ORION_SPI_INT_CAUSE_REG		0x10
 
+#define ORION_SPI_MODE_CPOL		(1 << 11)
+#define ORION_SPI_MODE_CPHA		(1 << 12)
 #define ORION_SPI_IF_8_16_BIT_MODE	(1 << 5)
 #define ORION_SPI_CLK_PRESCALE_MASK	0x1F
+#define ORION_SPI_MODE_MASK		(ORION_SPI_MODE_CPOL | \
+					 ORION_SPI_MODE_CPHA)
 
 struct orion_spi {
 	struct spi_master	*master;
@@ -123,6 +127,23 @@ static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
 	return 0;
 }
 
+static void
+orion_spi_mode_set(struct spi_device *spi)
+{
+	u32 reg;
+	struct orion_spi *orion_spi;
+
+	orion_spi = spi_master_get_devdata(spi->master);
+
+	reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
+	reg &= ~ORION_SPI_MODE_MASK;
+	if (spi->mode & SPI_CPOL)
+		reg |= ORION_SPI_MODE_CPOL;
+	if (spi->mode & SPI_CPHA)
+		reg |= ORION_SPI_MODE_CPHA;
+	writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
+}
+
 /*
  * called only when no transfer is active on the bus
  */
@@ -142,6 +163,8 @@ orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 	if ((t != NULL) && t->bits_per_word)
 		bits_per_word = t->bits_per_word;
 
+	orion_spi_mode_set(spi);
+
 	rc = orion_spi_baudrate_set(spi, speed);
 	if (rc)
 		return rc;
@@ -399,7 +422,7 @@ static int __init orion_spi_probe(struct platform_device *pdev)
 	}
 
 	/* we support only mode 0, and no options */
-	master->mode_bits = 0;
+	master->mode_bits = SPI_CPHA | SPI_CPOL;
 
 	master->setup = orion_spi_setup;
 	master->transfer_one_message = orion_spi_transfer_one_message;