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: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 38 insertions, 24 deletions

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 6656b2c82693..523da738805f 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;
 }
 
@@ -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;