Add haptic-control functionality to Apple M2's MTP touchpad

drivers/hid/Kconfig

@@ -146,6 +146,16 @@ config HID_APPLE
 	Say Y here if you want support for keyboards of	Apple iBooks, PowerBooks,
 	MacBooks, MacBook Pros and Apple Aluminum.
 
+config HID_APPLE_HAPTIC
+	tristate "Apple MTP Haptic Actuator support"
+	depends on HID
+	help
+          Say Y here if you want support for allowing a "Host controlled" touchpad mode
+          where userspace has control of manually triggering haptic click and deep-click
+          effects on the apple haptic trackpad. This is independent of the autonomous
+          clicking that triggers without userspace input by default.
+
+
 config HID_APPLEIR
 	tristate "Apple infrared receiver"
 	depends on (USB_HID)
@@ -739,6 +749,7 @@ config LOGIWHEELS_FF
 
 config HID_MAGICMOUSE
 	tristate "Apple Magic Mouse/Trackpad multi-touch support"
+	depends on (HID && HID_APPLE_HAPTIC) || HID_APPLE_HAPTIC=n
 	help
 	Support for the Apple Magic Mouse/Trackpad multi-touch.
 

drivers/hid/Makefile

@@ -29,6 +29,7 @@ obj-$(CONFIG_HID_ACCUTOUCH)	+= hid-accutouch.o
 obj-$(CONFIG_HID_ALPS)		+= hid-alps.o
 obj-$(CONFIG_HID_ACRUX)		+= hid-axff.o
 obj-$(CONFIG_HID_APPLE)		+= hid-apple.o
+obj-$(CONFIG_HID_APPLE_HAPTIC)	+= hid-apple-haptic.o
 obj-$(CONFIG_HID_APPLEIR)	+= hid-appleir.o
 obj-$(CONFIG_HID_APPLETB_BL)	+= hid-appletb-bl.o
 obj-$(CONFIG_HID_APPLETB_KBD)	+= hid-appletb-kbd.o

drivers/hid/dockchannel-hid/dockchannel-hid.c

@@ -593,12 +593,6 @@ static int dchid_get_report_cmd(struct dchid_iface *iface, u8 reportnum, void *b
 	return ret <= 0 ? ret : ret - 1;
 }
 
-/* Note: buf includes report number! */
-static int dchid_set_report(struct dchid_iface *iface, void *buf, size_t len)
-{
-	return dchid_cmd(iface, HID_OUTPUT_REPORT, REQ_SET_REPORT, buf, len, NULL, 0);
-}
-
 static int dchid_raw_request(struct hid_device *hdev,
 				unsigned char reportnum, __u8 *buf, size_t len,
 				unsigned char rtype, int reqtype)
@@ -610,7 +604,7 @@ static int dchid_raw_request(struct hid_device *hdev,
 		buf[0] = reportnum;
 		return dchid_cmd(iface, rtype, REQ_GET_REPORT, &reportnum, 1, buf + 1, len - 1);
 	case HID_REQ_SET_REPORT:
-		return dchid_set_report(iface, buf, len);
+		return dchid_cmd(iface, rtype, REQ_SET_REPORT, buf, len, NULL, 0);
 	default:
 		return -EIO;
 	}

drivers/hid/hid-apple-haptic.c

@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "asm-generic/errno-base.h"
+#include "hid-ids.h"
+#include "linux/gfp_types.h"
+#include "linux/hid.h"
+#include <linux/soc/apple/actuator.h>
+
+int apple_taptic_send(struct hid_device *haptic_hdev, u16 effect_type, u8 strength, u8 softness)
+{
+	int ret;
+	u8 *msg;
+	int msg_length;
+	u8 event_click[] = {0x53, 0x01, strength, softness, 0x03, 0x02, 0x22, 0x48, 0x49,
+			    0x01, 0x04, 0x60, 0x17, 0x2D, 0x03, 0x02, 0x18, 0x32, 0x1E};
+	u8 event_deep_click[] = {0x53, 0x01, strength, softness, 0x01, 0x07, 0x18, 0x18, 0x4F,
+				 0x02, 0x02, 0x60, 0x0C, 0x25};
+	u8 event_release[] = {0x53, 0x01, strength, softness};
+
+	switch (effect_type) {
+	case HID_HP_WAVEFORMPRESS & HID_USAGE:
+		msg = event_click;
+		msg_length = sizeof(event_click);
+		break;
+	case APPLE_HP_WAVEFORMDEEPCLICK & HID_USAGE:
+		msg = event_deep_click;
+		msg_length = sizeof(event_deep_click);
+		break;
+	case HID_HP_WAVEFORMRELEASE & HID_USAGE:
+		msg = event_release;
+		msg_length = sizeof(event_release);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	msg = kmemdup(msg, msg_length, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	ret = hid_hw_raw_request(haptic_hdev, msg[0], msg, msg_length,
+				 HID_OUTPUT_REPORT, HID_REQ_SET_REPORT);
+	kfree(msg);
+
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(apple_taptic_send);
+
+int apple_taptic_switch_modes(struct hid_device *haptic_hdev, bool enable_host_controlled)
+{
+	int ret;
+	u8 *buf;
+	u8 msg[] = { 0x21, enable_host_controlled };
+
+	buf = kmemdup(msg, sizeof(msg), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = hid_hw_raw_request(haptic_hdev, buf[0], buf, sizeof(msg),
+				 HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
+	kfree(buf);
+
+	if (ret < 0)
+		return ret;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(apple_taptic_switch_modes);
+
+static int apple_actuator_probe(struct hid_device *haptic_hdev, const struct hid_device_id *id)
+{
+	int ret;
+
+	ret = hid_parse(haptic_hdev);
+	if (ret) {
+		hid_err(haptic_hdev, "apple_haptic hid parse failed\n");
+		return ret;
+	}
+
+	ret = hid_hw_start(haptic_hdev, 0);
+	if (ret) {
+		hid_err(haptic_hdev, "apple_haptic hw start failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static bool actuator_match(struct hid_device *hdev, bool ignore_special_drivers)
+{
+	return (strcmp(hdev->name, "Apple MTP actuator") == 0);
+}
+
+static void actuator_remove(struct hid_device *haptic_hdev)
+{
+	apple_taptic_switch_modes(haptic_hdev, 0);
+	hid_hw_stop(haptic_hdev);
+}
+
+static const struct hid_device_id apple_haptic_devices[] = {
+	{ HID_DEVICE(BUS_HOST, HID_GROUP_ANY, HOST_VENDOR_ID_APPLE,
+		     HID_ANY_ID), .driver_data = 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, apple_haptic_devices);
+
+static struct hid_driver apple_actuator_driver = {
+	.name = "apple-trackpad-haptics",
+	.id_table = apple_haptic_devices,
+	.probe = apple_actuator_probe,
+	.match = actuator_match,
+	.remove = actuator_remove
+};
+module_hid_driver(apple_actuator_driver);
+
+MODULE_DESCRIPTION("Apple MTP Haptic Actuator driver");
+MODULE_LICENSE("GPL");