spi: altera: Simplify altera_spi_txrx implementation for noirq case

This patch simplifies the code and makes it better in readability.
Now the logic in the while loop is simply
"write to ALTERA_SPI_TXDATA then read from ALTERA_SPI_TXDATA".

There is a slightly logic change because now we avoid a read-write cycle when
hw->len is 0. Since the code in bitbang library will call bitbang->txrx_bufs()
only when t->len is not 0, this is not a problem.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Mark Brown <broonie@linaro.org>

diff --git a/drivers/spi/spi-altera.c b/drivers/spi/spi-altera.c
index 81b9adb6e766bdae0b0f6c9de4836ecfaffc490a..453fa5ac04ade9eecb8df73549d0d2f754995aaa 100644 (file)
--- a/drivers/spi/spi-altera.c
+++ b/drivers/spi/spi-altera.c
@@ -150,12 +150,12 @@ static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
                hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
                writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
        } else {
-               /* send the first byte */
-               writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
-
-               while (1) {
+               while (hw->count < hw->len) {
                        unsigned int rxd;
 
+                       writel(hw_txbyte(hw, hw->count),
+                              hw->base + ALTERA_SPI_TXDATA);
+
                        while (!(readl(hw->base + ALTERA_SPI_STATUS) &
                                 ALTERA_SPI_STATUS_RRDY_MSK))
                                cpu_relax();
@@ -174,14 +174,7 @@ static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
                        }
 
                        hw->count++;
-
-                       if (hw->count < hw->len)
-                               writel(hw_txbyte(hw, hw->count),
-                                      hw->base + ALTERA_SPI_TXDATA);
-                       else
-                               break;
                }
-
        }
 
        return hw->count * hw->bytes_per_word;