[PATCH v4 42/48] Input: Atmel: handle ReportID "0x00" while processing T5 messages

[Jiada Wang]

From: Deepak Das <deepak_das@xxxxxxxxxx>

ReportID "0x00" is reserved by Atmel and should not be used by any
Atmel touch controller.

reportID is the first byte retrieved from T5 message payload.
Currently Atmel driver continues to process the T5 messages even if
the reportID "0x00" is returned by Touch Controller.

This commit modifies Atmel touch driver to return -EINVAL if ReportID
"0x00" is received while processing T5 messages.

Signed-off-by: Deepak Das <deepak_das@xxxxxxxxxx>
Signed-off-by: George G. Davis <george_davis@xxxxxxxxxx>
Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index e02097193229..7a5b0bd4b82e 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -76,6 +76,7 @@
 #define MXT_PROCI_TOUCHSEQUENCELOGGER	93
 #define MXT_TOUCH_MULTITOUCHSCREEN_T100 100
 #define MXT_PROCI_ACTIVESTYLUS_T107	107
+#define MXT_RPTID_RESERVED		0
 
 /* MXT_GEN_MESSAGE_T5 object */
 #define MXT_RPTID_NOMSG		0xff
@@ -1384,6 +1385,11 @@ static int mxt_proc_message(struct mxt_data *data, u8 *message)
 	u8 report_id = message[0];
 	bool dump = data->debug_enabled;
 
+	if (report_id == MXT_RPTID_RESERVED) {
+		dev_err(&data->client->dev,
+			"Received Reserved ReportID 0x00\n");
+		return -EINVAL;
+	}
 	if (report_id == MXT_RPTID_NOMSG)
 		return 0;
 
@@ -1454,6 +1460,8 @@ static int mxt_read_and_process_messages(struct mxt_data *data, u8 count)
 		ret = mxt_proc_message(data,
 			data->msg_buf + data->T5_msg_size * i);
 
+		if (ret < 0)
+			return ret;
 		if (ret == 1)
 			num_valid++;
 	}
-- 
2.17.1