diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
index f15f695777f8ff6b0c352a948a9a1bc0fe942a2f..b9f0fb2530e2357cb1f39ff1e52d48cf764ccc1b 100644
--- a/drivers/input/mouse/psmouse-base.c
+++ b/drivers/input/mouse/psmouse-base.c
@@ -177,6 +177,15 @@ static psmouse_ret_t psmouse_process_byte(struct psmouse *psmouse)
 		packet[1] |= (packet[0] & 0x40) << 1;
 	}
 
+/*
+ * Cortron PS2 Trackball reports SIDE button on the 4th bit of the first
+ * byte.
+ */
+	if (psmouse->type == PSMOUSE_CORTRON) {
+		input_report_key(dev, BTN_SIDE, (packet[0] >> 3) & 1);
+		packet[0] |= 0x08;
+	}
+
 /*
  * Generic PS/2 Mouse
  */
@@ -539,6 +548,20 @@ static int ps2bare_detect(struct psmouse *psmouse, int set_properties)
 	return 0;
 }
 
+/*
+ * Cortron PS/2 protocol detection. There's no special way to detect it, so it
+ * must be forced by sysfs protocol writing.
+ */
+static int cortron_detect(struct psmouse *psmouse, int set_properties)
+{
+	if (set_properties) {
+		psmouse->vendor = "Cortron";
+		psmouse->name = "PS/2 Trackball";
+		set_bit(BTN_SIDE, psmouse->dev->keybit);
+	}
+
+	return 0;
+}
 
 /*
  * psmouse_extensions() probes for any extensions to the basic PS/2 protocol
@@ -739,6 +762,12 @@ static const struct psmouse_protocol psmouse_protocols[] = {
 		.detect		= touchkit_ps2_detect,
 	},
 #endif
+	{
+		.type		= PSMOUSE_CORTRON,
+		.name		= "CortronPS/2",
+		.alias		= "cortps",
+		.detect		= cortron_detect,
+	},
 	{
 		.type		= PSMOUSE_AUTO,
 		.name		= "auto",
diff --git a/drivers/input/mouse/psmouse.h b/drivers/input/mouse/psmouse.h
index 3964e8acbc54da1b96c2f67fd12bc9f13ca61151..27a68835b5ba1559cd3a498a1730cd18de516d8e 100644
--- a/drivers/input/mouse/psmouse.h
+++ b/drivers/input/mouse/psmouse.h
@@ -88,6 +88,7 @@ enum psmouse_type {
 	PSMOUSE_LIFEBOOK,
 	PSMOUSE_TRACKPOINT,
 	PSMOUSE_TOUCHKIT_PS2,
+	PSMOUSE_CORTRON,
 	PSMOUSE_AUTO		/* This one should always be last */
 };