staging: comedi: das16: fail attach if board id is incorrect

This driver probes the board id during the attach to ensure that the
user is attempting to attach to the correct board type. Currently an
error message is output if the ids are not consistent but the attach
continues anyway.

Make the attach fail if the id bits do not match. Also, cleanup the
printk messages and use a dev_err() only if the probe fails.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/das16.c

@@ -974,11 +974,11 @@ static int das16_probe(struct comedi_device *dev, struct comedi_devconfig *it)
 
 	/* diobits indicates boards */
 	diobits = inb(dev->iobase + DAS16_DIO_REG) & 0xf0;
-
-	printk(KERN_INFO " id bits are 0x%02x\n", diobits);
 	if (board->id != diobits) {
-		printk(KERN_INFO " requested board's id bits are 0x%x (ignore)\n",
-		       board->id);
+		dev_err(dev->class_dev,
+			"requested board's id bits are incorrect (0x%x != 0x%x)\n",
+			board->id, diobits);
+		return -EINVAL;
 	}
 
 	return 0;
@@ -1054,10 +1054,8 @@ static int das16_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	}
 
 	/*  probe id bits to make sure they are consistent */
-	if (das16_probe(dev, it)) {
-		printk(KERN_ERR " id bits do not match selected board, aborting\n");
+	if (das16_probe(dev, it))
 		return -EINVAL;
-	}
 
 	/*  get master clock speed */
 	if (devpriv->can_burst) {