spi: synquacer: simplify tx completion checking

There is a TX-FIFO and Shift Register empty(TFES) status
bit in spi controller. This commit checks the TFES bit
to wait the TX transfer completes.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Signed-off-by: Satoru Okamoto <okamoto.satoru@socionext.com>
Acked-by: Jassi Brar <jaswinder.singh@linaro.org>

diff --git a/drivers/spi/spi-synquacer.c b/drivers/spi/spi-synquacer.c
index 5e1b3ae..0cae3df 100644 (file)
--- a/drivers/spi/spi-synquacer.c
+++ b/drivers/spi/spi-synquacer.c
@@ -45,6 +45,7 @@
 #define RXF            0x20
 #define RXE            0x24
 #define RXC            0x28
+#define TFES           1
 #define TFLETE         4
 #define TSSRS          6
 #define RFMTE          5
@@ -345,13 +346,10 @@ static int synquacer_spi_xfer(struct udevice *dev, unsigned int bitlen,
                if (priv->tx_words) {
                        write_fifo(priv);
                } else {
-                       u32 len;
-
-                       do { /* wait for shifter to empty out */
+                       /* wait for shifter to empty out */
+                       while (!(readl(priv->base + TXF) & BIT(TFES)))
                                cpu_relax();
-                               len = readl(priv->base + DMSTATUS);
-                               len = (len >> TX_DATA_SHIFT) & TX_DATA_MASK;
-                       } while (tx_buf && len);
+
                        busy &= ~BIT(TXBIT);
                }
        }