linux-kernel - [PATCH v2] spi: omap2-mcspi: Add support for GPIO chipselects

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Date:	Sun, 26 Apr 2015 22:44:30 -0500
From:	Michael Welling <mwelling@...e.org>
To:	broonie@...nel.org, linux-spi@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	Michael Welling <mwelling@...e.org>
Subject: [PATCH v2] spi: omap2-mcspi: Add support for GPIO chipselects

This patch allows for GPIOs specified in the devicetree to be used as SPI
chipselects on TI OMAP2 SoCs.

Tested on the AM3354.

Signed-off-by: Michael Welling <mwelling@...e.org>
---

v2: Considers the possible use of SPI_CS_HIGH during chip select activation.

 drivers/spi/spi-omap2-mcspi.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index d1a5b9f..5e388a8 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -35,6 +35,7 @@
 #include <linux/gcd.h>
 
 #include <linux/spi/spi.h>
+#include <linux/gpio.h>
 
 #include <linux/platform_data/spi-omap2-mcspi.h>
 
@@ -246,6 +247,12 @@ static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active)
 {
 	u32 l;
 
+	if (gpio_is_valid(spi->cs_gpio)) {
+		gpio_set_value(spi->cs_gpio, (cs_active) ?
+			!!(spi->mode & SPI_CS_HIGH) :
+			!(spi->mode & SPI_CS_HIGH));
+	}
+
 	l = mcspi_cached_chconf0(spi);
 	if (cs_active)
 		l |= OMAP2_MCSPI_CHCONF_FORCE;
@@ -1015,6 +1022,12 @@ static int omap2_mcspi_setup(struct spi_device *spi)
 	if (ret < 0)
 		return ret;
 
+	if (gpio_is_valid(spi->cs_gpio)) {
+		if (gpio_request(spi->cs_gpio, dev_name(&spi->dev)) == 0)
+			gpio_direction_output(spi->cs_gpio,
+				!(spi->mode & SPI_CS_HIGH));
+	}
+
 	ret = omap2_mcspi_setup_transfer(spi, NULL);
 	pm_runtime_mark_last_busy(mcspi->dev);
 	pm_runtime_put_autosuspend(mcspi->dev);
-- 
1.7.9.5

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