The "dt2815" driver uses an admin-supplied configuration option
(`it->options[0]`) to configure the I/O port base address of a DT2815
board.  It currently allows any base address to be configured but the
hardware only supports base addresses (configured by an on-board DIP
switch) in the range 0x200 to 0x3fe on 2-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/dt2815.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/comedi/drivers/dt2815.c b/drivers/comedi/drivers/dt2815.c
index 03ba2fd18a21..3fa184451523 100644
--- a/drivers/comedi/drivers/dt2815.c
+++ b/drivers/comedi/drivers/dt2815.c
@@ -144,7 +144,8 @@ static int dt2815_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	const struct comedi_lrange *current_range_type, *voltage_range_type;
 	int ret;
 
-	ret = comedi_request_region(dev, it->options[0], 0x2);
+	ret = comedi_check_request_region(dev, it->options[0], 0x2,
+					  0x200, 0x3ff, 2);
 	if (ret)
 		return ret;
 
-- 
2.51.0