[PATCH 5.4 145/155] staging: kpc2000: prevent underflow in cpld_reconfigure()

[Greg Kroah-Hartman]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

commit 72db61d7d17a475d3cc9de1a7c871d518fcd82f0 upstream.

This function should not allow negative values of "wr_val".  If
negatives are allowed then capping the upper bound at 7 is
meaningless.  Let's make it unsigned.

Fixes: 7dc7967fc39a ("staging: kpc2000: add initial set of Daktronics drivers")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200224103325.hrxdnaeqsthplu42@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/staging/kpc2000/kpc2000/core.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/staging/kpc2000/kpc2000/core.c
+++ b/drivers/staging/kpc2000/kpc2000/core.c
@@ -110,10 +110,10 @@ static ssize_t cpld_reconfigure(struct d
 				const char *buf, size_t count)
 {
 	struct kp2000_device *pcard = dev_get_drvdata(dev);
-	long wr_val;
+	unsigned long wr_val;
 	int rv;
 
-	rv = kstrtol(buf, 0, &wr_val);
+	rv = kstrtoul(buf, 0, &wr_val);
 	if (rv < 0)
 		return rv;
 	if (wr_val > 7)