[PATCH 02/11] Input: serio - store the pt_buttons in the struct serio directly

[Benjamin Tissoires]

With RMI4 over SMBus, the pass-through device can be instantiated
in a SMBus driver. However, compared to the psmouse-synaptics driver,
this pass-through PS/2 driver has no clue whether the current
serio_interrupt() is the beginning of the frame or not. Instead of
adding a protocol analysis in RMI4 function F03, we can add an extra
byte in struct serio to handle the extra data we want to append to the
first byte.

Convert the psmouse-synaptics device to use it too.

Partially reverts cdd9dc1 ("Input: synaptics - re-route tracksticks
buttons on the Lenovo 2015 series")

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
 drivers/input/mouse/psmouse-base.c |  3 +++
 drivers/input/mouse/synaptics.c    | 19 ++++++++++---------
 drivers/input/mouse/synaptics.h    |  1 -
 include/linux/serio.h              |  8 ++++++++
 4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index 5784e20..dbc002a 100644
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -365,6 +365,9 @@ static irqreturn_t psmouse_interrupt(struct serio *serio,
 		goto out;
 	}
 
+	if (psmouse->pktcnt == 1)
+		psmouse->packet[0] |= serio->extra_byte;
+
 	psmouse->last = jiffies;
 	psmouse_handle_byte(psmouse);
 
diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c
index a41d832..8781e23 100644
--- a/drivers/input/mouse/synaptics.c
+++ b/drivers/input/mouse/synaptics.c
@@ -597,15 +597,13 @@ static int synaptics_is_pt_packet(unsigned char *buf)
 	return (buf[0] & 0xFC) == 0x84 && (buf[3] & 0xCC) == 0xC4;
 }
 
-static void synaptics_pass_pt_packet(struct psmouse *psmouse,
-				     struct serio *ptport,
+static void synaptics_pass_pt_packet(struct serio *ptport,
 				     unsigned char *packet)
 {
-	struct synaptics_data *priv = psmouse->private;
 	struct psmouse *child = serio_get_drvdata(ptport);
 
 	if (child && child->state == PSMOUSE_ACTIVATED) {
-		serio_interrupt(ptport, packet[1] | priv->pt_buttons, 0);
+		serio_interrupt(ptport, packet[1], 0);
 		serio_interrupt(ptport, packet[4], 0);
 		serio_interrupt(ptport, packet[5], 0);
 		if (child->pktsize == 4)
@@ -857,6 +855,7 @@ static void synaptics_report_ext_buttons(struct psmouse *psmouse,
 	struct synaptics_data *priv = psmouse->private;
 	int ext_bits = (SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap) + 1) >> 1;
 	char buf[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+	int pt_buttons;
 	int i;
 
 	if (!SYN_CAP_MULTI_BUTTON_NO(priv->ext_cap))
@@ -887,11 +886,13 @@ static void synaptics_report_ext_buttons(struct psmouse *psmouse,
 		return;
 
 	/* The trackstick expects at most 3 buttons */
-	priv->pt_buttons = SYN_CAP_EXT_BUTTON_STICK_L(hw->ext_buttons)      |
-			   SYN_CAP_EXT_BUTTON_STICK_R(hw->ext_buttons) << 1 |
-			   SYN_CAP_EXT_BUTTON_STICK_M(hw->ext_buttons) << 2;
+	pt_buttons = SYN_CAP_EXT_BUTTON_STICK_L(hw->ext_buttons)      |
+		     SYN_CAP_EXT_BUTTON_STICK_R(hw->ext_buttons) << 1 |
+		     SYN_CAP_EXT_BUTTON_STICK_M(hw->ext_buttons) << 2;
+
+	priv->pt_port->extra_byte = pt_buttons;
 
-	synaptics_pass_pt_packet(psmouse, priv->pt_port, buf);
+	synaptics_pass_pt_packet(priv->pt_port, buf);
 }
 
 static void synaptics_report_buttons(struct psmouse *psmouse,
@@ -1132,7 +1133,7 @@ static psmouse_ret_t synaptics_process_byte(struct psmouse *psmouse)
 		if (SYN_CAP_PASS_THROUGH(priv->capabilities) &&
 		    synaptics_is_pt_packet(psmouse->packet)) {
 			if (priv->pt_port)
-				synaptics_pass_pt_packet(psmouse, priv->pt_port,
+				synaptics_pass_pt_packet(priv->pt_port,
 							 psmouse->packet);
 		} else
 			synaptics_process_packet(psmouse);
diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h
index 56faa7e..116ae25 100644
--- a/drivers/input/mouse/synaptics.h
+++ b/drivers/input/mouse/synaptics.h
@@ -183,7 +183,6 @@ struct synaptics_data {
 	bool disable_gesture;			/* disable gestures */
 
 	struct serio *pt_port;			/* Pass-through serio port */
-	unsigned char pt_buttons;		/* Pass-through buttons */
 
 	/*
 	 * Last received Advanced Gesture Mode (AGM) packet. An AGM packet
diff --git a/include/linux/serio.h b/include/linux/serio.h
index c733cff..f3b75c8 100644
--- a/include/linux/serio.h
+++ b/include/linux/serio.h
@@ -64,6 +64,14 @@ struct serio {
 	 * may get indigestion when exposed to concurrent access (i8042).
 	 */
 	struct mutex *ps2_cmd_mutex;
+
+	/*
+	 * For use with Synaptics devices that have the trackstick buttons
+	 * not actually wired to the trackstick PS/2 device.
+	 * This byte will be OR-ed with the first byte of the incoming packet
+	 * that contains actual data (not commands).
+	 */
+	u8 extra_byte;
 };
 #define to_serio_port(d)	container_of(d, struct serio, dev)
 
-- 
2.5.5