For v2 hardware, there is no real parity check, but we can still checkIf you add some comments, as suggest by Dmitry, it looks perfect :-)
some constant bits for data integrity.
Signed-off-by: JJ Ding<jj_ding@xxxxxxxxxx>
---
drivers/input/mouse/elantech.c | 26 +++++++++++++++++++++++---
1 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index cf41f23..032181c 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -376,6 +376,25 @@ static int elantech_check_parity_v1(struct psmouse *psmouse)
etd->parity[packet[3]] == p3;
}
+static int packet_simple_check_v2(struct psmouse *psmouse)
+{
+ struct elantech_data *etd = psmouse->private;
+ unsigned char *packet = psmouse->packet;
+
+ if (etd->reports_pressure)
+ return (packet[0]& 0x0c) == 0x04&&
+ (packet[3]& 0x0f) == 0x02;
+
+ if ((packet[0]& 0xc0) == 0x80)
+ return (packet[0]& 0x0c) == 0x0c&&
+ (packet[3]& 0x0e) == 0x08;
+
+ return (packet[0]& 0x3c) == 0x3c&&
+ (packet[1]& 0xf0) == 0x00&&
+ (packet[3]& 0x3e) == 0x38&&
+ (packet[4]& 0xf0) == 0x00;
+}
+
/*
* Process byte stream from mouse and handle complete packets
*/
@@ -398,7 +417,9 @@ static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
break;
case 2:
- /* We don't know how to check parity in protocol v2 */
+ if (etd->paritycheck&& !packet_simple_check_v2(psmouse))
+ return PSMOUSE_BAD_DATA;
+
elantech_report_absolute_v2(psmouse);
break;
}
@@ -799,8 +820,7 @@ int elantech_init(struct psmouse *psmouse)
etd->hw_version = 2;
/* For now show extra debug information */
etd->debug = 1;
- /* Don't know how to do parity checking for version 2 */
- etd->paritycheck = 0;
+ etd->paritycheck = 1;
if (etd->fw_version>= 0x020800)
etd->reports_pressure = true;