[PATCH] input: alps-fix the issue the special alps trackpoint do not work.

[XiaoXiao Liu]

when the alps trackpoint is detected and using the alps_v8_protocol_data
procotol, the alps driver will not report the input data.

solution: use standard mouse driver instead of alps driver when the specail
trackpoint was detected.

Signed-off-by: XiaoXiao Liu <sliuuxiaonxiao@xxxxxxxxx>
---
 drivers/input/mouse/alps.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 0a6f7ca883e7..516ae1d0eb17 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -24,7 +24,7 @@
 
 #include "psmouse.h"
 #include "alps.h"
-
+#include "trackpoint.h"
 /*
  * Definitions for ALPS version 3 and 4 command mode protocol
  */
@@ -2864,6 +2864,22 @@ static const struct alps_protocol_info *alps_match_table(unsigned char *e7,
 	return NULL;
 }
 
+int alps_check_is_trackpoint(struct psmouse *psmouse)
+{
+	u8 param[2] = { 0 };
+	int error;
+
+	error = ps2_command(&psmouse->ps2dev,
+			    param, MAKE_PS2_CMD(0, 2, TP_READ_ID));
+	if (error)
+		return error;
+
+	if (param[0] == TP_VARIANT_ALPS)
+		return 0;
+	psmouse_warn(psmouse, "It is not alps trackpoint.\n");
+	return -ENODEV;
+}
+
 static int alps_identify(struct psmouse *psmouse, struct alps_data *priv)
 {
 	const struct alps_protocol_info *protocol;
@@ -2912,6 +2928,11 @@ static int alps_identify(struct psmouse *psmouse, struct alps_data *priv)
 			protocol = &alps_v3_protocol_data;
 		} else if (e7[0] == 0x73 && e7[1] == 0x03 &&
 			   (e7[2] == 0x14 || e7[2] == 0x28)) {
+				if (alps_check_is_trackpoint(psmouse) == 0) {
+					psmouse_warn(psmouse,
+					"It is alps trackpoint, use the standard mouse driver.\n");
+					return -EINVAL;
+				}
 			protocol = &alps_v8_protocol_data;
 		} else if (e7[0] == 0x73 && e7[1] == 0x03 && e7[2] == 0xc8) {
 			protocol = &alps_v9_protocol_data;
-- 
2.20.1