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| author | Chris Packham <chris.packham@alliedtelesis.co.nz> | 2017-05-23 16:03:21 +1200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2017-05-24 18:02:43 +0100 |
| commit | b28b9149b37f909a05f1e06e5a8b262a519dbd2b (patch) | |
| tree | 4a2b3ec73e6eb564f6cbf0630dea7933f0fce806 | |
| parent | 2ea659a9ef488125eb46da6eb571de5eae5c43f6 (diff) | |
| download | lwn-b28b9149b37f909a05f1e06e5a8b262a519dbd2b.tar.gz lwn-b28b9149b37f909a05f1e06e5a8b262a519dbd2b.zip | |
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>
| -rw-r--r-- | drivers/spi/spi-orion.c | 10 |
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); |