From 1021dcf19db1387bc0db26d14bbcba719923a466 Mon Sep 17 00:00:00 2001
From: Anson Huang <Anson.Huang@nxp.com>
Date: Fri, 13 Dec 2019 14:02:30 -0800
Subject: [PATCH] Input: imx_sc_key - only take the valid data from SCU
firmware as key state
When reading key state from SCU, the response data from SCU firmware
is 4 bytes due to MU message protocol, but ONLY the first byte is the
key state, other 3 bytes could be some dirty data, so we should ONLY
take the first byte as key state to avoid reporting incorrect state.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Fixes: 688f1dfb69b4 ("Input: keyboard - imx_sc: Add i.MX system controller key support")
Link: https://lore.kernel.org/r/1576202909-1661-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
drivers/input/keyboard/imx_sc_key.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/input/keyboard/imx_sc_key.c b/drivers/input/keyboard/imx_sc_key.c
index 53799527dc75b..9f809aeb785c4 100644
--- a/drivers/input/keyboard/imx_sc_key.c
+++ b/drivers/input/keyboard/imx_sc_key.c
@@ -78,7 +78,13 @@ static void imx_sc_check_for_events(struct work_struct *work)
return;
}
- state = (bool)msg.state;
+ /*
+ * The response data from SCU firmware is 4 bytes,
+ * but ONLY the first byte is the key state, other
+ * 3 bytes could be some dirty data, so we should
+ * ONLY take the first byte as key state.
+ */
+ state = (bool)(msg.state & 0xff);
if (state ^ priv->keystate) {
priv->keystate = state;