The "s526" driver uses an admin-supplied configuration option
(`it->options[0]`) to configure the I/O port base address of a Sensoray
526 board.  It currently allows any base address to be configured but
the hardware only supports base addresses (configured by on-board DIP
switches) in the range 0 to 0xFFC0 on 64-byte boundaries.

Add a sanity check to ensure the device is not configured at an
unsupported base address.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
---
 drivers/comedi/drivers/s526.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/comedi/drivers/s526.c b/drivers/comedi/drivers/s526.c
index 9245c679a3c4..dd27c754dea4 100644
--- a/drivers/comedi/drivers/s526.c
+++ b/drivers/comedi/drivers/s526.c
@@ -553,7 +553,8 @@ static int s526_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	struct comedi_subdevice *s;
 	int ret;
 
-	ret = comedi_request_region(dev, it->options[0], 0x40);
+	ret = comedi_check_request_region(dev, it->options[0], 0x40,
+					  0, 0xffc0, 64);
 	if (ret)
 		return ret;
 
-- 
2.51.0