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Commit f9c6ef6c authored by Ricardo Ribalda Delgado's avatar Ricardo Ribalda Delgado Committed by Mark Brown
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spi/xilinx: Support for spi mode CS_HIGH 



The core controls the chip select lines individually.

By default, all the lines are consider active_low. After
spi_setup_transfer, it has its real value.

Signed-off-by: default avatarRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent d9f58812

drivers/spi/spi-xilinx.c

+38 −24
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ struct xilinx_spi { 
	int remaining_bytes;	/* the number of bytes left to transfer */

	u8 bits_per_word;

	int buffer_size;	/* buffer size in words */

	u32 cs_inactive;	/* Level of the CS pins when inactive*/

	unsigned int (*read_fn)(void __iomem *);

	void (*write_fn)(u32, void __iomem *);

	void (*tx_fn)(struct xilinx_spi *);
@@ -194,14 +195,17 @@ static void xspi_init_hw(struct xilinx_spi *xspi) 
static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)

{

	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);

	u16 cr;

	u32 cs;



	if (is_on == BITBANG_CS_INACTIVE) {

		/* Deselect the slave on the SPI bus */

		xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);

	} else if (is_on == BITBANG_CS_ACTIVE) {

		xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET);

		return;

	}



	/* Set the SPI clock phase and polarity */

		u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)

			 & ~XSPI_CR_MODE_MASK;

	cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)	& ~XSPI_CR_MODE_MASK;

	if (spi->mode & SPI_CPHA)

		cr |= XSPI_CR_CPHA;

	if (spi->mode & SPI_CPOL)
@@ -217,10 +221,11 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) 
	 * parameter)

	 */



	cs = xspi->cs_inactive;

	cs ^= BIT(spi->chip_select);



	/* Activate the chip select */

		xspi->write_fn(~(0x0001 << spi->chip_select),

			xspi->regs + XSPI_SSR_OFFSET);

	}

	xspi->write_fn(cs, xspi->regs + XSPI_SSR_OFFSET);

}



/* spi_bitbang requires custom setup_transfer() to be defined if there is a
@@ -229,6 +234,13 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) 
static int xilinx_spi_setup_transfer(struct spi_device *spi,

		struct spi_transfer *t)

{

	struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);



	if (spi->mode & SPI_CS_HIGH)

		xspi->cs_inactive &= ~BIT(spi->chip_select);

	else

		xspi->cs_inactive |= BIT(spi->chip_select);



	return 0;

}
@@ -376,9 +388,11 @@ static int xilinx_spi_probe(struct platform_device *pdev) 
		return -ENODEV;



	/* the spi->mode bits understood by this driver: */

	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP;

	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP |

			    SPI_CS_HIGH;



	xspi = spi_master_get_devdata(master);

	xspi->cs_inactive = 0xffffffff;

	xspi->bitbang.master = master;

	xspi->bitbang.chipselect = xilinx_spi_chipselect;

	xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;