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 3219656..9a855bb 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -409,6 +409,8 @@
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 @@
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 @@
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;