spi/pxa2xx: fix incorrect SW mode chipselect setting for BayTrail LPSS SPI

It was observed that after module removal followed by insertion,
the SW mode chipselect is not properly set. Thus causing transfer
failure due to incorrect CS toggling.

Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index a98df7e..fe79210 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -118,6 +118,7 @@
 	 */
 	orig = readl(drv_data->ioaddr + offset + SPI_CS_CONTROL);
 
+	/* Test SPI_CS_CONTROL_SW_MODE bit enabling */
 	value = orig | SPI_CS_CONTROL_SW_MODE;
 	writel(value, drv_data->ioaddr + offset + SPI_CS_CONTROL);
 	value = readl(drv_data->ioaddr + offset + SPI_CS_CONTROL);
@@ -126,10 +127,13 @@
 		goto detection_done;
 	}
 
-	value &= ~SPI_CS_CONTROL_SW_MODE;
+	orig = readl(drv_data->ioaddr + offset + SPI_CS_CONTROL);
+
+	/* Test SPI_CS_CONTROL_SW_MODE bit disabling */
+	value = orig & ~SPI_CS_CONTROL_SW_MODE;
 	writel(value, drv_data->ioaddr + offset + SPI_CS_CONTROL);
 	value = readl(drv_data->ioaddr + offset + SPI_CS_CONTROL);
-	if (value != orig) {
+	if (value != (orig & ~SPI_CS_CONTROL_SW_MODE)) {
 		offset = 0x800;
 		goto detection_done;
 	}