From: Vishnu Sankar <vishnuocv@gmail.com>
Date: Wed, 11 Mar 2026 14:31:42 +0000 (+0900)
Subject: input: trackpoint - Enable doubletap by default on capable devices
X-Git-Tag: v7.1-rc1~71^2~87
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9a98ebe630cf13c1a6063afa676d1cecc44fb2c9;p=thirdparty%2Fkernel%2Fstable.git

input: trackpoint - Enable doubletap by default on capable devices

Enable doubletap functionality by default on TrackPoint devices that
support it. The feature is detected using firmware ID pattern matching
(PNP: LEN03xxx) with a deny list of incompatible devices.

This provides immediate doubletap functionality without requiring
userspace configuration. The hardware is enabled during device
detection, while event filtering continues to be handled by the
thinkpad_acpi driver as before.

Signed-off-by: Vishnu Sankar <vishnuocv@gmail.com>
Suggested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://patch.msgid.link/20260311143144.482145-2-vishnuocv@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---

diff --git a/drivers/input/mouse/trackpoint.c b/drivers/input/mouse/trackpoint.c
index b06c7ad721fe9..3bd8fdf56cd3d 100644
--- a/drivers/input/mouse/trackpoint.c
+++ b/drivers/input/mouse/trackpoint.c
@@ -5,6 +5,7 @@
  * Trademarks are the property of their respective owners.
  */
 
+#include <linux/array_size.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/serio.h>
@@ -12,6 +13,7 @@
 #include <linux/input.h>
 #include <linux/libps2.h>
 #include <linux/proc_fs.h>
+#include <linux/string.h>
 #include <linux/uaccess.h>
 #include "psmouse.h"
 #include "trackpoint.h"
@@ -393,6 +395,44 @@ static int trackpoint_reconnect(struct psmouse *psmouse)
 	return 0;
 }
 
+/* List of known incapable device PNP IDs */
+static const char * const dt_incompatible_devices[] = {
+	"LEN0304",
+	"LEN0306",
+	"LEN0317",
+	"LEN031A",
+	"LEN031B",
+	"LEN031C",
+	"LEN031D",
+};
+
+/*
+ * Checks if it's a doubletap capable device.
+ * The PNP ID format is "PNP: LEN030d PNP0f13".
+ */
+static bool trackpoint_is_dt_capable(const char *pnp_id)
+{
+	size_t i;
+
+	if (!pnp_id)
+		return false;
+
+	/* Must start with "PNP: LEN03" */
+	if (!strstarts(pnp_id, "PNP: LEN03"))
+		return false;
+
+	/* Ensure enough length before comparing */
+	if (strlen(pnp_id) < 12)
+		return false;
+
+	/* Check deny-list */
+	for (i = 0; i < ARRAY_SIZE(dt_incompatible_devices); i++) {
+		if (!strncmp(pnp_id + 5, dt_incompatible_devices[i], 7))
+			return false;
+	}
+	return true;
+}
+
 int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
 {
 	struct ps2dev *ps2dev = &psmouse->ps2dev;
@@ -470,6 +510,12 @@ int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
 		     psmouse->vendor, firmware_id,
 		     (button_info & 0xf0) >> 4, button_info & 0x0f);
 
+	if (trackpoint_is_dt_capable(ps2dev->serio->firmware_id)) {
+		error = trackpoint_write(ps2dev, TP_DOUBLETAP, TP_DOUBLETAP_ENABLE);
+		if (error)
+			psmouse_warn(psmouse, "Failed to enable doubletap: %d\n", error);
+	}
+
 	return 0;
 }
 
diff --git a/drivers/input/mouse/trackpoint.h b/drivers/input/mouse/trackpoint.h
index eb5412904fe07..3e03cdb394498 100644
--- a/drivers/input/mouse/trackpoint.h
+++ b/drivers/input/mouse/trackpoint.h
@@ -69,6 +69,8 @@
 					/* (how hard it is to drag */
 					/* with Z-axis pressed) */
 
+#define TP_DOUBLETAP		0x58	/* TrackPoint doubletap register */
+
 #define TP_MINDRAG		0x59	/* Minimum amount of force needed */
 					/* to trigger dragging */
 
@@ -110,6 +112,9 @@
 					   external device will be forced to 1 */
 #define TP_MASK_EXT_TAG			0x04
 
+/* Doubletap register values */
+#define TP_DOUBLETAP_ENABLE	0xFF	/* Enable value */
+#define TP_DOUBLETAP_DISABLE	0xFE	/* Disable value */
 
 /* Power on Self Test Results */
 #define TP_POR_SUCCESS		0x3B