spi: dw-mid: split dma_setup() from dma_transfer()

The patch splits DMA preparatory code to dma_setup() callback. The change also
converts transfer_one() to program DMA whenever the transfer is DMA mapped. The
change is a follow up of the converion to use SPI core transfer_one_message().
Since the DMA mapped transfers can be interleaved with PIO ones the DMA related
configuration should respect that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index 25c8fa7..4b4d266 100644
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -207,12 +207,10 @@
 	return rxdesc;
 }
 
-static void dw_spi_dma_setup(struct dw_spi *dws)
+static int mid_spi_dma_setup(struct dw_spi *dws)
 {
 	u16 dma_ctrl = 0;
 
-	spi_enable_chip(dws, 0);
-
 	dw_writew(dws, DW_SPI_DMARDLR, 0xf);
 	dw_writew(dws, DW_SPI_DMATDLR, 0x10);
 
@@ -222,21 +220,17 @@
 		dma_ctrl |= SPI_DMA_RDMAE;
 	dw_writew(dws, DW_SPI_DMACR, dma_ctrl);
 
-	spi_enable_chip(dws, 1);
+	return 0;
 }
 
-static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
+static int mid_spi_dma_transfer(struct dw_spi *dws)
 {
 	struct dma_async_tx_descriptor *txdesc, *rxdesc;
 
-	/* 1. setup DMA related registers */
-	if (cs_change)
-		dw_spi_dma_setup(dws);
-
-	/* 2. Prepare the TX dma transfer */
+	/* Prepare the TX dma transfer */
 	txdesc = dw_spi_dma_prepare_tx(dws);
 
-	/* 3. Prepare the RX dma transfer */
+	/* Prepare the RX dma transfer */
 	rxdesc = dw_spi_dma_prepare_rx(dws);
 
 	/* rx must be started before tx due to spi instinct */
@@ -258,6 +252,7 @@
 static struct dw_spi_dma_ops mid_dma_ops = {
 	.dma_init	= mid_spi_dma_init,
 	.dma_exit	= mid_spi_dma_exit,
+	.dma_setup	= mid_spi_dma_setup,
 	.dma_transfer	= mid_spi_dma_transfer,
 };
 #endif