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Commit 0b2e8915 authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Mark Brown
Browse files

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: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 45746e82

drivers/spi/spi-dw.c

+15 −23
Original line number Diff line number Diff line
@@ -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);

	}



	if (cs_change)

		dws->prev_chip = chip;