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spi: orion: Add multiple chip select support to spi-orion 

This commit adds support for multiple hardware chip selects to spi-orion.
Different SoCs support different number of chip selects (up to
8 on some platforms). The driver allows up to this number, and it is up
to the implementer to only use the chip selects that are available.

Signed-off-by: Ken Wilson <ken.wilson@opengear.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Ken Wilson 2015-01-16 13:10:47 +10:00 committed by Mark Brown
parent 75872ebe96
commit 23244404e2
1 changed files with 14 additions and 1 deletions
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15
drivers/spi/spi-orion.c
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@ -28,7 +28,12 @@
/* Runtime PM autosuspend timeout: PM is fairly light on this driver */
#define SPI_AUTOSUSPEND_TIMEOUT 200
#define ORION_NUM_CHIPSELECTS 1 /* only one slave is supported*/
/* Some SoCs using this driver support up to 8 chip selects.
* It is up to the implementer to only use the chip selects
* that are available.
*/
#define ORION_NUM_CHIPSELECTS 8
#define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
#define ORION_SPI_IF_CTRL_REG 0x00
@ -44,6 +49,10 @@
#define ARMADA_SPI_CLK_PRESCALE_MASK 0xDF
#define ORION_SPI_MODE_MASK (ORION_SPI_MODE_CPOL | \
ORION_SPI_MODE_CPHA)
#define ORION_SPI_CS_MASK 0x1C
#define ORION_SPI_CS_SHIFT 2
#define ORION_SPI_CS(cs) ((cs << ORION_SPI_CS_SHIFT) & \
ORION_SPI_CS_MASK)
enum orion_spi_type {
ORION_SPI,
@ -221,6 +230,10 @@ static void orion_spi_set_cs(struct spi_device *spi, bool enable)
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));
/* Chip select logic is inverted from spi_set_cs */
if (!enable)
orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);