[PATCH v2 5/7] Input: iqs7222 - protect against undefined slider size

[Jeff LaBundy <jeff@labundy.com>]

Select variants of silicon do not define a default slider size, in
which case the size must be specified in the device tree. If it is
not, the axis's maximum value is reported as 65535 due to unsigned
integer overflow.

To solve this problem, move the existing zero-check outside of the
conditional block that checks whether the property is present.

Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
Changes in v2:
 - Rebased to account for changes earlier in series

 drivers/input/misc/iqs7222.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
index 36c3b24e99a3..0a592b90f471 100644
--- a/drivers/input/misc/iqs7222.c
+++ b/drivers/input/misc/iqs7222.c
@@ -2042,7 +2042,7 @@ static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222,
 
 	error = fwnode_property_read_u32(sldr_node, "azoteq,slider-size", &val);
 	if (!error) {
-		if (!val || val > dev_desc->sldr_res) {
+		if (val > dev_desc->sldr_res) {
 			dev_err(&client->dev, "Invalid %s size: %u\n",
 				fwnode_get_name(sldr_node), val);
 			return -EINVAL;
@@ -2061,6 +2061,13 @@ static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222,
 		return error;
 	}
 
+	if (!(reg_offset ? sldr_setup[3]
+			 : sldr_setup[2] & IQS7222_SLDR_SETUP_2_RES_MASK)) {
+		dev_err(&client->dev, "Undefined %s size\n",
+			fwnode_get_name(sldr_node));
+		return -EINVAL;
+	}
+
 	error = fwnode_property_read_u32(sldr_node, "azoteq,top-speed", &val);
 	if (!error) {
 		if (val > (reg_offset ? U16_MAX : U8_MAX * 4)) {
-- 
2.34.1