spi: dw: add support for gpio controlled chip select

Also, use this opportunity to let spi_chip_sel() handle chip-select
deactivation as well.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 1492f5ee9aaa..a5cba14ac3d2 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -16,6 +16,7 @@
 #include <linux/spi/spi.h>
 #include <linux/scatterlist.h>
 #include <linux/module.h>
+#include <linux/of_gpio.h>
 
 #include "spi-dw.h"
 
@@ -70,6 +71,27 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
 	dws->num_cs = 4;
 	dws->max_freq = clk_get_rate(dwsmmio->clk);
 
+	if (pdev->dev.of_node) {
+		int i;
+
+		for (i = 0; i < dws->num_cs; i++) {
+			int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
+					"cs-gpios", i);
+
+			if (cs_gpio == -EPROBE_DEFER) {
+				ret = cs_gpio;
+				goto out;
+			}
+
+			if (gpio_is_valid(cs_gpio)) {
+				ret = devm_gpio_request(&pdev->dev, cs_gpio,
+						dev_name(&pdev->dev));
+				if (ret)
+					goto out;
+			}
+		}
+	}
+
 	ret = dw_spi_add_host(&pdev->dev, dws);
 	if (ret)
 		goto out;