[PATCH] Input: elants_i2c - prevent divide-by-zero on invalid EKTH data

[Laxman Acharya Padhya]

elants_i2c_query_ts_info_ekth() checks the reported row, column and
oversampling values before calculating the touchscreen resolution, but
does not check the physical dimensions. If either physical dimension
is zero, DIV_ROUND_CLOSEST() divides by zero during probe.

Treat zero physical dimensions as invalid data and skip the resolution
calculation, as is already done for the other invalid information.

Fixes: 66aee90088da ("Input: add support for Elan eKTH I2C touchscreens")
Assisted-by: Codex:gpt-5
Signed-off-by: Laxman Acharya Padhya <acharyalaxman8848@xxxxxxxxx>
---
 drivers/input/touchscreen/elants_i2c.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index 17175ad..68c5ee3 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -566,10 +566,11 @@ static int elants_i2c_query_ts_info_ekth(struct elants_data *ts)
 
 	dev_dbg(&client->dev, "phy_x=%d, phy_y=%d\n", phy_x, phy_y);
 
-	if (rows == 0 || cols == 0 || osr == 0) {
+	if (rows == 0 || cols == 0 || osr == 0 ||
+	    phy_x == 0 || phy_y == 0) {
 		dev_warn(&client->dev,
-			 "invalid trace number data: %d, %d, %d\n",
-			 rows, cols, osr);
+			 "invalid data: rows=%u cols=%u osr=%u phy_x=%u phy_y=%u\n",
+			 rows, cols, osr, phy_x, phy_y);
 	} else {
 		/* translate trace number to TS resolution */
 		ts->x_max = ELAN_TS_RESOLUTION(rows, osr);
-- 
2.51.2