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authorChris Packham <chris.packham@alliedtelesis.co.nz>2017-05-23 07:03:21 +0300
committerMark Brown <broonie@kernel.org>2017-05-24 20:02:43 +0300
commitb28b9149b37f909a05f1e06e5a8b262a519dbd2b (patch)
tree4a2b3ec73e6eb564f6cbf0630dea7933f0fce806 /drivers/spi/spi-orion.c
parent2ea659a9ef488125eb46da6eb571de5eae5c43f6 (diff)
downloadlinux-b28b9149b37f909a05f1e06e5a8b262a519dbd2b.tar.xz
spi: orion: Handle GPIO chip-selects
Some hardware designs use GPIOs to add (or supplement) the SPI chip-select so that more than one SPI slave device can be used. For this to work with the spi-orion driver the SPI_MASTER_GPIO_SS flag needs to be set (because the other outputs are gated internally by the CS) and the correct chip-select (in this case CS0) needs to be driven by the controller. Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-orion.c')
-rw-r--r--drivers/spi/spi-orion.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c
index be2e87ee8b31..28fc9f161b9d 100644
--- a/drivers/spi/spi-orion.c
+++ b/drivers/spi/spi-orion.c
@@ -22,6 +22,7 @@
#include <linux/of_device.h>
#include <linux/clk.h>
#include <linux/sizes.h>
+#include <linux/gpio.h>
#include <asm/unaligned.h>
#define DRIVER_NAME "orion_spi"
@@ -320,12 +321,18 @@ orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
static void orion_spi_set_cs(struct spi_device *spi, bool enable)
{
struct orion_spi *orion_spi;
+ int cs;
+
+ if (gpio_is_valid(spi->cs_gpio))
+ cs = 0;
+ else
+ cs = spi->chip_select;
orion_spi = spi_master_get_devdata(spi->master);
orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, ORION_SPI_CS_MASK);
orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG,
- ORION_SPI_CS(spi->chip_select));
+ ORION_SPI_CS(cs));
/* Chip select logic is inverted from spi_set_cs */
if (!enable)
@@ -606,6 +613,7 @@ static int orion_spi_probe(struct platform_device *pdev)
master->setup = orion_spi_setup;
master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
master->auto_runtime_pm = true;
+ master->flags = SPI_MASTER_GPIO_SS;
platform_set_drvdata(pdev, master);