[PATCH 10/18] spi/xilinx: Support for spi mode CS_HIGH

From: Ricardo Ribalda Delgado
Date: Fri Jan 23 2015 - 11:09:18 EST


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@xxxxxxxxx>
---
drivers/spi/spi-xilinx.c | 62 +++++++++++++++++++++++++++++-------------------
1 file changed, 38 insertions(+), 24 deletions(-)

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index a70cb91..29edf1b 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -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;
}

@@ -369,9 +381,11 @@ 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;
--
2.1.4

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