spi/xilinx: Check number of slaves range

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>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 337fda4e78a6..2ca55f6b5158 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 XILINX_SPI_MAX_CS       32
+
 #define XILINX_SPI_NAME "xilinx_spi"
 
 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
@@ -347,6 +349,11 @@ static int xilinx_spi_probe(struct platform_device *pdev)
                 return -EINVAL;
         }
 
+        if (num_cs > XILINX_SPI_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;