NFC: NCI: allow spi driver to choose transfer clock

In some cases low level drivers might want to update the
SPI transfer clock (e.g. during firmware download).

This patch adds this support. Without any modification the
driver will use the default SPI clock (from pdata or device tree).

Signed-off-by: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/net/nfc/nci/spi.c b/net/nfc/nci/spi.c
index 25153d0..d904cd2 100644
--- a/net/nfc/nci/spi.c
+++ b/net/nfc/nci/spi.c
@@ -58,6 +58,7 @@
 	}
 	t.cs_change = cs_change;
 	t.delay_usecs = nspi->xfer_udelay;
+	t.speed_hz = nspi->xfer_speed_hz;
 
 	spi_message_init(&m);
 	spi_message_add_tail(&t, &m);
@@ -144,7 +145,8 @@
 
 	nspi->acknowledge_mode = acknowledge_mode;
 	nspi->xfer_udelay = delay;
-
+	/* Use controller max SPI speed by default */
+	nspi->xfer_speed_hz = 0;
 	nspi->spi = spi;
 	nspi->ndev = ndev;
 	init_completion(&nspi->req_completion);
@@ -197,12 +199,14 @@
 	tx.tx_buf = req;
 	tx.len = 2;
 	tx.cs_change = 0;
+	tx.speed_hz = nspi->xfer_speed_hz;
 	spi_message_add_tail(&tx, &m);
 
 	memset(&rx, 0, sizeof(struct spi_transfer));
 	rx.rx_buf = resp_hdr;
 	rx.len = 2;
 	rx.cs_change = 1;
+	rx.speed_hz = nspi->xfer_speed_hz;
 	spi_message_add_tail(&rx, &m);
 
 	ret = spi_sync(nspi->spi, &m);
@@ -226,6 +230,7 @@
 	rx.len = rx_len;
 	rx.cs_change = 0;
 	rx.delay_usecs = nspi->xfer_udelay;
+	rx.speed_hz = nspi->xfer_speed_hz;
 	spi_message_add_tail(&rx, &m);
 
 	ret = spi_sync(nspi->spi, &m);