Messages in this thread Patch in this message | | | From | Chris Packham <> | Subject | [PATCH 1/2] spi: orion: Handle GPIO chip-selects | Date | Tue, 23 May 2017 16:03:21 +1200 |
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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> --- drivers/spi/spi-orion.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
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); -- 2.13.0
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