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spi/xilinx: Support for spi mode CS_HIGH

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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: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Ricardo Ribalda Delgado 2015-01-28 13:23:46 +01:00 committed by Mark Brown
parent d9f5881242
commit f9c6ef6cfe
1 changed files with 38 additions and 24 deletions
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62
drivers/spi/spi-xilinx.c
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@ -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 *);
@ -194,33 +195,37 @@ 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) {
/* Set the SPI clock phase and polarity */
u16 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)
cr |= XSPI_CR_CPOL;
if (spi->mode & SPI_LSB_FIRST)
cr |= XSPI_CR_LSB_FIRST;
if (spi->mode & SPI_LOOP)
cr |= XSPI_CR_LOOP;
xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
/* We do not check spi->max_speed_hz here as the SPI clock
* frequency is not software programmable (the IP block design
* parameter)
*/
/* Activate the chip select */
xspi->write_fn(~(0x0001 << spi->chip_select),
xspi->regs + XSPI_SSR_OFFSET);
xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET);
return;
}
/* Set the SPI clock phase and polarity */
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)
cr |= XSPI_CR_CPOL;
if (spi->mode & SPI_LSB_FIRST)
cr |= XSPI_CR_LSB_FIRST;
if (spi->mode & SPI_LOOP)
cr |= XSPI_CR_LOOP;
xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
/* We do not check spi->max_speed_hz here as the SPI clock
* frequency is not software programmable (the IP block design
* parameter)
*/
cs = xspi->cs_inactive;
cs ^= BIT(spi->chip_select);
/* Activate the chip select */
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;