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Commit b28b9149 authored by Chris Packham's avatar Chris Packham Committed by Mark Brown
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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: default avatarChris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 2ea659a9

drivers/spi/spi-orion.c

+9 −1
Original line number Diff line number Diff line
@@ -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);