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
tionality,
one simply provides a table mapping CS line numbers to GPIO numbers
omap2_mcspi_platform_config.cs_gpios.
Signed-off-by: Ben Gamari <bgamari.foss@xxxxxxxxx>
---
arch/arm/plat-omap/include/plat/mcspi.h | 1 +
drivers/spi/omap2_mcspi.c | 19 +++++++++++++++++--
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/arch/arm/plat-omap/include/plat/mcspi.h b/arch/arm/plat-omap/include/plat/mcspi.h
index 3d51b18..c5670f2 100644
--- a/arch/arm/plat-omap/include/plat/mcspi.h
+++ b/arch/arm/plat-omap/include/plat/mcspi.h
@@ -10,6 +10,7 @@
struct omap2_mcspi_platform_config {
unsigned short num_cs;
unsigned int regs_offset;
+ int *cs_gpios;
};
struct omap2_mcspi_dev_attr {
diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index f41c906..20dec5d 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -36,6 +36,7 @@
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
+#include <linux/gpio.h>
#include <plat/dma.h>
#include <plat/clock.h>
@@ -121,6 +122,7 @@ struct omap2_mcspi {
/* SPI1 has 4 channels, while SPI2 has 2 */
struct omap2_mcspi_dma *dma_channels;
struct device *dev;
+ int *cs_gpios;
};
struct omap2_mcspi_cs {
@@ -227,7 +229,11 @@ 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;
+ struct omap2_mcspi* mcspi = spi_master_get_devdata(spi->master);
+ if (mcspi->cs_gpios)
+ gpio_set_value(mcspi->cs_gpios[spi->chip_select], cs_active);
+ // TXS times out unless we force the CHCONF reg as well
l = mcspi_cached_chconf0(spi);
MOD_REG_BIT(l, OMAP2_MCSPI_CHCONF_FORCE, cs_active);
mcspi_write_chconf0(spi, l);
@@ -1088,6 +1094,8 @@ static int __init omap2_mcspi_probe(struct platform_device *pdev)
struct omap2_mcspi *mcspi;
struct resource *r;
int status = 0, i;
+ struct omap2_mcspi_platform_config* pconfig = pdev->dev.platform_data;
+ int num_dma;
master = spi_alloc_master(&pdev->dev, sizeof *mcspi);
if (master == NULL) {
@@ -1110,6 +1118,13 @@ static int __init omap2_mcspi_probe(struct platform_device *pdev)
mcspi = spi_master_get_devdata(master);
mcspi->master = master;
+ if (pconfig && pconfig->cs_gpios) {
+ mcspi->cs_gpios = pconfig->cs_gpios;
+ num_dma = 1;
+ } else {
+ mcspi->cs_gpios = NULL;
+ num_dma = master->num_chipselect;
+ }
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (r == NULL) {
@@ -1139,14 +1154,14 @@ static int __init omap2_mcspi_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&mcspi->msg_queue);
INIT_LIST_HEAD(&omap2_mcspi_ctx[master->bus_num - 1].cs);
- mcspi->dma_channels = kcalloc(master->num_chipselect,
+ mcspi->dma_channels = kcalloc(num_dma,
sizeof(struct omap2_mcspi_dma),
GFP_KERNEL);
if (mcspi->dma_channels == NULL)
goto err2;
- for (i = 0; i < master->num_chipselect; i++) {
+ for (i = 0; i < num_dma; i++) {
char dma_ch_name[14];
struct resource *dma_res;
--
1.7.4.1
--
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