[PATCH] Input: hynitron-cst816x - ignore unsupported gestures

The controller reports 0x05 for single click and 0x0b for double
click, while the binding only defines keycode mappings for the four
swipe gestures and long press. cst816x_gest_idx() currently maps every
other nonzero gesture to the long-press slot, so unsupported gesture
IDs can be reported using the long-press keycode.

Return an invalid slot for unsupported gesture IDs and check it against
the number of configured keycodes before reporting the event.

Fixes: c87a819bec86 ("Input: add driver for Hynitron CST816x series")
Cc: [email protected]
Signed-off-by: Jianing Li <[email protected]>
---
 drivers/input/touchscreen/hynitron-cst816x.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/input/touchscreen/hynitron-cst816x.c b/drivers/input/touchscreen/hynitron-cst816x.c
index 47d9cd7412d1b..d0668ac96f9af 100644
--- a/drivers/input/touchscreen/hynitron-cst816x.c
+++ b/drivers/input/touchscreen/hynitron-cst816x.c
@@ -92,24 +92,19 @@ static int cst816x_i2c_read_register(struct cst816x_priv *priv, u8 reg,
 	return 0;
 }
 
-static u8 cst816x_gest_idx(u8 gest)
+static unsigned int cst816x_gest_idx(u8 gest)
 {
-	u8 index;
-
 	switch (gest) {
 	case 0x01: /* Slide up gesture */
 	case 0x02: /* Slide down gesture */
 	case 0x03: /* Slide left gesture */
 	case 0x04: /* Slide right gesture */
-		index = gest;
-		break;
+		return gest - 1;
 	case 0x0c: /* Long press gesture */
+		return CST816X_NUM_KEYS - 1;
 	default:
-		index = CST816X_NUM_KEYS;
-		break;
+		return CST816X_NUM_KEYS;
 	}
-
-	return index - 1;
 }
 
 static bool cst816x_process_touch(struct cst816x_priv *priv,
@@ -169,6 +164,7 @@ static irqreturn_t cst816x_irq_cb(int irq, void *cookie)
 {
 	struct cst816x_priv *priv = cookie;
 	struct cst816x_touch tch;
+	unsigned int gest_idx;
 
 	if (!cst816x_process_touch(priv, &tch))
 		return IRQ_HANDLED;
@@ -176,9 +172,10 @@ static irqreturn_t cst816x_irq_cb(int irq, void *cookie)
 	input_report_abs(priv->input, ABS_X, tch.abs_x);
 	input_report_abs(priv->input, ABS_Y, tch.abs_y);
 
-	if (tch.gest)
+	gest_idx = cst816x_gest_idx(tch.gest);
+	if (gest_idx < priv->keycodemax)
 		input_report_key(priv->input,
-				 priv->keycode[cst816x_gest_idx(tch.gest)],
+				 priv->keycode[gest_idx],
 				 tch.active);
 
 	input_report_key(priv->input, BTN_TOUCH, tch.active);
-- 
2.23.0.windows.1