[PATCH v2 2/4] platform/x86: thinkpad_acpi: Support for trackpoint doubletap

[Mark Pearson <mpearson-lenovo@squebb.ca>]

Lenovo trackpoints are adding the ability to generate a doubletap event.
This handles the doubletap event and sends the KEY_PROG1 event to
userspace.

Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Vishnu Sankar <vishnuocv@gmail.com>
---
Changes in v2:
 - Use KEY_PROG1 instead of KEY_DOUBLETAP as input maintainer doesn't
   want new un-specific key codes added.
 - Add doubletap to hotkey scan code table and use existing hotkey
   functionality.
 - Tested using evtest, and then gnome settings to configure a custom shortcut
   to launch an application.

 drivers/platform/x86/thinkpad_acpi.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 3b48d893280f..6d04d45e8d45 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -232,6 +232,9 @@ enum tpacpi_hkey_event_t {
 
 	/* Misc */
 	TP_HKEY_EV_RFKILL_CHANGED	= 0x7000, /* rfkill switch changed */
+
+	/* Misc2 */
+	TP_HKEY_EV_TRACK_DOUBLETAP      = 0x8036, /* trackpoint doubletap */
 };
 
 /****************************************************************************
@@ -1786,6 +1789,7 @@ enum {	/* hot key scan codes (derived from ACPI DSDT) */
 	TP_ACPI_HOTKEYSCAN_NOTIFICATION_CENTER,
 	TP_ACPI_HOTKEYSCAN_PICKUP_PHONE,
 	TP_ACPI_HOTKEYSCAN_HANGUP_PHONE,
+	TP_ACPI_HOTKEYSCAN_DOUBLETAP,
 
 	/* Hotkey keymap size */
 	TPACPI_HOTKEY_MAP_LEN
@@ -3336,6 +3340,7 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 		KEY_NOTIFICATION_CENTER,	/* Notification Center */
 		KEY_PICKUP_PHONE,		/* Answer incoming call */
 		KEY_HANGUP_PHONE,		/* Decline incoming call */
+		KEY_PROG1,                      /* Trackpoint doubletap */
 		},
 	};
 
@@ -3996,6 +4001,15 @@ static bool hotkey_notify_6xxx(const u32 hkey,
 	return true;
 }
 
+static bool hotkey_notify_8xxx(const u32 hkey)
+{
+	if (hkey == TP_HKEY_EV_TRACK_DOUBLETAP) {
+		tpacpi_input_send_key(TP_ACPI_HOTKEYSCAN_DOUBLETAP);
+		return true;
+	}
+	return false;
+}
+
 static void hotkey_notify(struct ibm_struct *ibm, u32 event)
 {
 	u32 hkey;
@@ -4079,6 +4093,10 @@ static void hotkey_notify(struct ibm_struct *ibm, u32 event)
 				known_ev = true;
 			}
 			break;
+		case 8:
+			/* 0x8000-0x8FFF: misc2 */
+			known_ev = hotkey_notify_8xxx(hkey);
+			break;
 		}
 		if (!known_ev) {
 			pr_notice("unhandled HKEY event 0x%04x\n", hkey);
-- 
2.44.0