spi: dw: program registers as soon as possible

This patch refactors the code in pump_transfers() to reprogram the registers
immediately when we have a new configuration data. The behaviour is slightly
modified:
 - chip is always disabled and reenabled
 - CTRL0 is always reprogrammed

This change allows to do a further refactoring and simplier conversion to use
SPI core DMA routines in the future.

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.c b/drivers/spi/spi-dw.c
index 321965607fc040a02d208dec203bbf38cb6555ee..9a855bb006940f37cbfdb280fdf57522b36d8849 100644 (file)
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -409,6 +409,8 @@ static void pump_transfers(unsigned long data)
        if (chip != dws->prev_chip)
                cs_change = 1;
 
+       spi_enable_chip(dws, 0);
+
        cr0 = chip->cr0;
 
        /* Handle per transfer options for bpw and speed */
@@ -423,6 +425,8 @@ static void pump_transfers(unsigned long data)
 
                        chip->speed_hz = speed;
                        chip->clk_div = clk_div;
+
+                       spi_set_clk(dws, chip->clk_div);
                }
        }
        if (transfer->bits_per_word) {
@@ -451,44 +455,32 @@ static void pump_transfers(unsigned long data)
                cr0 |= (chip->tmode << SPI_TMOD_OFFSET);
        }
 
+       dw_writew(dws, DW_SPI_CTRL0, cr0);
+       spi_chip_sel(dws, spi, 1);
+
        /* Check if current transfer is a DMA transaction */
        dws->dma_mapped = map_dma_buffers(dws);
 
+       /* For poll mode just disable all interrupts */
+       spi_mask_intr(dws, 0xff);
+
        /*
         * Interrupt mode
         * we only need set the TXEI IRQ, as TX/RX always happen syncronizely
         */
        if (!dws->dma_mapped && !chip->poll_mode) {
                txlevel = min_t(u16, dws->fifo_len / 2, dws->len / dws->n_bytes);
+               dw_writew(dws, DW_SPI_TXFLTR, txlevel);
 
+               /* Set the interrupt mask */
                imask |= SPI_INT_TXEI | SPI_INT_TXOI |
                         SPI_INT_RXUI | SPI_INT_RXOI;
+               spi_umask_intr(dws, imask);
+
                dws->transfer_handler = interrupt_transfer;
        }
 
-       /*
-        * Reprogram registers only if
-        *      1. chip select changes
-        *      2. clk_div is changed
-        *      3. control value changes
-        */
-       if (dw_readw(dws, DW_SPI_CTRL0) != cr0 || cs_change || clk_div || imask) {
-               spi_enable_chip(dws, 0);
-
-               dw_writew(dws, DW_SPI_CTRL0, cr0);
-
-               spi_set_clk(dws, chip->clk_div);
-               spi_chip_sel(dws, spi, 1);
-
-               /* Set the interrupt mask, for poll mode just disable all int */
-               spi_mask_intr(dws, 0xff);
-               if (imask)
-                       spi_umask_intr(dws, imask);
-               if (txlevel)
-                       dw_writew(dws, DW_SPI_TXFLTR, txlevel);
-
-               spi_enable_chip(dws, 1);
-       }
+       spi_enable_chip(dws, 1);
 
        if (cs_change)
                dws->prev_chip = chip;