[PATCH 1/2] mcspi: Add support for GPIO chip select lines

[Ben Gamari <bgamari.foss-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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 specifies the GPIO number in spi_board_info.controller_data.

Signed-off-by: Ben Gamari <bgamari.foss-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/spi/omap2_mcspi.c |   13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index 951a160..ca4a7dc 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 +236,13 @@ 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);
+	if (spi->controller_data) {
+                gpio_set_value((unsigned) spi->controller_data, 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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