The "fl512" driver uses an admin-supplied configuration option
(`it->options[0]`) to configure the I/O port base address of an FL512
board.  It currently allows any base address to be configured and uses a
16-byte register region.

I cannot find any information about this board, but assume it needs to
be aligned to a 16-byte boundary.  I have no idea about the allowed
range, so allow anything in a 32-bit range and add a "FIXME" comment
(although most ancient ISA cards only support 10-bit address decoding).
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/dt282x.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/comedi/drivers/dt282x.c b/drivers/comedi/drivers/dt282x.c
index 4ae80e6c7266..29832e1f062d 100644
--- a/drivers/comedi/drivers/dt282x.c
+++ b/drivers/comedi/drivers/dt282x.c
@@ -1064,7 +1064,12 @@ static int dt282x_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	struct comedi_subdevice *s;
 	int ret;
 
-	ret = comedi_request_region(dev, it->options[0], 0x10);
+	/*
+	 * Although it has only 16 bytes (8 16-bit registers), it needs to
+	 * start on a 32-byte boundary in range 0x200 to 0x3E0.
+	 */
+	ret = comedi_check_request_region(dev, it->options[0], 0x10,
+					  0x200, 0x3ff, 32);
 	if (ret)
 		return ret;
 
-- 
2.51.0