Many applications require more chip select lines than the board or
processor allow. Introduce a mechanism to allow use of GPIO pins as
chip select lines with the McSPI controller. To use this functionality,
one simply provides a table mapping CS line numbers to GPIO numbers in
omap2_mcspi_platform_config.cs_gpios.
Signed-off-by: Ben Gamari <bgamari.foss@xxxxxxxxx>
---
arch/arm/plat-omap/include/plat/mcspi.h | 3 ++-
drivers/spi/omap2_mcspi.c | 15 ++++++++++-----
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/arch/arm/plat-omap/include/plat/mcspi.h b/arch/arm/plat-omap/include/plat/mcspi.h
index 1254e49..cac1d84 100644
--- a/arch/arm/plat-omap/include/plat/mcspi.h
+++ b/arch/arm/plat-omap/include/plat/mcspi.h
@@ -2,7 +2,8 @@
#define _OMAP2_MCSPI_H
struct omap2_mcspi_platform_config {
- unsigned short num_cs;
+ unsigned short num_cs;
+ int *cs_gpios;
};
struct omap2_mcspi_device_config {
diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index abb1ffb..59cbed4 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -35,6 +35,7 @@
#include <linux/slab.h>
#include <linux/spi/spi.h>
+#include <linux/gpio.h>
#include <plat/dma.h>
#include <plat/clock.h>
@@ -235,11 +236,15 @@ static void omap2_mcspi_set_enable(const struct spi_device *spi, int enable)
static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active)
{
- u32 l;
-
- l = mcspi_cached_chconf0(spi);
- MOD_REG_BIT(l, OMAP2_MCSPI_CHCONF_FORCE, cs_active);
- mcspi_write_chconf0(spi, l);
+ struct omap2_mcspi_platform_config *pconfig = spi->master->dev.platform_data;
+ if (pconfig->cs_gpios) {
+ int gpio = pconfig->cs_gpios[spi->chip_select];
+ gpio_set_value(gpio, cs_active);
+ } else {
+ u32 l = mcspi_cached_chconf0(spi);
+ MOD_REG_BIT(l, OMAP2_MCSPI_CHCONF_FORCE, cs_active);
+ mcspi_write_chconf0(spi, l);
+ }
}
static void omap2_mcspi_set_master_mode(struct spi_master *master)
--
1.7.0.4
--
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