[PATCH 18/18] spi/xilinx: Check number of slaves range

[Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>]

The core only supports up to 32 slaves, and the chipselect function
expects the same.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 drivers/spi/spi-xilinx.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 026f4c5..134d8cd 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -22,6 +22,8 @@
 #include <linux/spi/xilinx_spi.h>
 #include <linux/io.h>
 
+#define MAX_CS			32
+
 #define XILINX_SPI_NAME "xilinx_spi"
 
 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
@@ -340,6 +342,11 @@ static int xilinx_spi_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	if (num_cs > MAX_CS) {
+		dev_err(&pdev->dev, "Invalid number of spi slaves\n");
+		return -EINVAL;
+	}
+
 	master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
 	if (!master)
 		return -ENODEV;
-- 
2.1.4