HID: add support for the eGalax dual-touch panel

Added support for the eGalax dual-touch panel, found on the Asus EeePC T101MT

Signed-off-by: Stephane Chatty <chatty@enac.fr>
Tested-by: Philipp Merkel <linux@philmerk.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 280 insertions, 0 deletions

diff --git a/drivers/hid/hid-egalax.c b/drivers/hid/hid-egalax.c
new file mode 100644
index 000000000000..8b48d5a07179
--- /dev/null
+++ b/drivers/hid/hid-egalax.c
@@ -0,0 +1,280 @@
+/*
+ *  HID driver for eGalax dual-touch panels
+ *
+ *  Copyright (c) 2010 Stephane Chatty <chatty@enac.fr>
+ *
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include "usbhid/usbhid.h"
+
+MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
+MODULE_DESCRIPTION("eGalax dual-touch panel");
+MODULE_LICENSE("GPL");
+
+#include "hid-ids.h"
+
+struct egalax_data {
+	__u16 x, y, z;
+	__u8 id;
+	bool first;		/* is this the first finger in the frame? */
+	bool valid;		/* valid finger data, or just placeholder? */
+	bool activity;		/* at least one active finger previously? */
+	__u16 lastx, lasty;	/* latest valid (x, y) in the frame */
+};
+
+static int egalax_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	switch (usage->hid & HID_USAGE_PAGE) {
+
+	case HID_UP_GENDESK:
+		switch (usage->hid) {
+		case HID_GD_X:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_POSITION_X);
+			/* touchscreen emulation */
+			input_set_abs_params(hi->input, ABS_X,
+						field->logical_minimum,
+						field->logical_maximum, 0, 0);
+			return 1;
+		case HID_GD_Y:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_POSITION_Y);
+			/* touchscreen emulation */
+			input_set_abs_params(hi->input, ABS_Y,
+						field->logical_minimum,
+						field->logical_maximum, 0, 0);
+			return 1;
+		}
+		return 0;
+
+	case HID_UP_DIGITIZER:
+		switch (usage->hid) {
+		case HID_DG_TIPSWITCH:
+			/* touchscreen emulation */
+			hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
+			return 1;
+		case HID_DG_INRANGE:
+		case HID_DG_CONFIDENCE:
+		case HID_DG_CONTACTCOUNT:
+		case HID_DG_CONTACTMAX:
+			return -1;
+		case HID_DG_CONTACTID:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_TRACKING_ID);
+			return 1;
+		case HID_DG_TIPPRESSURE:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_PRESSURE);
+			return 1;
+		}
+		return 0;
+	}
+
+	/* ignore others (from other reports we won't get anyway) */
+	return -1;
+}
+
+static int egalax_input_mapped(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	if (usage->type == EV_KEY || usage->type == EV_ABS)
+		clear_bit(usage->code, *bit);
+
+	return 0;
+}
+
+/*
+ * this function is called when a whole finger has been parsed,
+ * so that it can decide what to send to the input layer.
+ */
+static void egalax_filter_event(struct egalax_data *td, struct input_dev *input)
+{
+	td->first = !td->first; /* touchscreen emulation */
+
+	if (td->valid) {
+		/* emit multitouch events */
+		input_event(input, EV_ABS, ABS_MT_TRACKING_ID, td->id);
+		input_event(input, EV_ABS, ABS_MT_POSITION_X, td->x);
+		input_event(input, EV_ABS, ABS_MT_POSITION_Y, td->y);
+		input_event(input, EV_ABS, ABS_MT_PRESSURE, td->z);
+
+		input_mt_sync(input);
+
+		/*
+		 * touchscreen emulation: store (x, y) as
+		 * the last valid values in this frame
+		 */
+		td->lastx = td->x;
+		td->lasty = td->y;
+	}
+
+	/*
+	 * touchscreen emulation: if this is the second finger and at least
+	 * one in this frame is valid, the latest valid in the frame is
+	 * the oldest on the panel, the one we want for single touch
+	 */
+	if (!td->first && td->activity) {
+		input_event(input, EV_ABS, ABS_X, td->lastx);
+		input_event(input, EV_ABS, ABS_Y, td->lasty);
+	}
+
+	if (!td->valid) {
+		/*
+		 * touchscreen emulation: if the first finger is invalid
+		 * and there previously was finger activity, this is a release
+		 */ 
+		if (td->first && td->activity) {
+			input_event(input, EV_KEY, BTN_TOUCH, 0);
+			td->activity = false;
+		}
+		return;
+	}
+
+
+	/* touchscreen emulation: if no previous activity, emit touch event */
+	if (!td->activity) {
+		input_event(input, EV_KEY, BTN_TOUCH, 1);
+		td->activity = true;
+	}
+}
+
+
+static int egalax_event(struct hid_device *hid, struct hid_field *field,
+				struct hid_usage *usage, __s32 value)
+{
+	struct egalax_data *td = hid_get_drvdata(hid);
+
+	if (hid->claimed & HID_CLAIMED_INPUT) {
+		struct input_dev *input = field->hidinput->input;
+
+		switch (usage->hid) {
+		case HID_DG_INRANGE:
+		case HID_DG_CONFIDENCE:
+			/* avoid interference from generic hidinput handling */
+			break;
+		case HID_DG_TIPSWITCH:
+			td->valid = value;
+			break;
+		case HID_DG_TIPPRESSURE:
+			td->z = value;
+			break;
+		case HID_DG_CONTACTID:
+			td->id = value;
+			break;
+		case HID_GD_X:
+			td->x = value;
+			break;
+		case HID_GD_Y:
+			td->y = value;
+			/* this is the last field in a finger */
+			egalax_filter_event(td, input);
+			break;
+		case HID_DG_CONTACTCOUNT:
+			/* touch emulation: this is the last field in a frame */
+			td->first = false;
+			break;
+
+		default:
+			/* fallback to the generic hidinput handling */
+			return 0;
+		}
+	}
+
+	/* we have handled the hidinput part, now remains hiddev */
+	if (hid->claimed & HID_CLAIMED_HIDDEV && hid->hiddev_hid_event)
+		hid->hiddev_hid_event(hid, field, usage, value);
+
+	return 1;
+}
+
+static int egalax_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+	struct egalax_data *td;
+	struct hid_report *report;
+
+	td = kmalloc(sizeof(struct egalax_data), GFP_KERNEL);
+	if (!td) {
+		dev_err(&hdev->dev, "cannot allocate eGalax data\n");
+		return -ENOMEM;
+	}
+	hid_set_drvdata(hdev, td);
+
+	ret = hid_parse(hdev);
+	if (ret)
+		goto end;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret)
+		goto end;
+
+	report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[5]; 
+	if (report) {
+		report->field[0]->value[0] = 2;
+		usbhid_submit_report(hdev, report, USB_DIR_OUT);
+	}
+
+end:
+	if (ret)
+		kfree(td);
+
+	return ret;
+}
+
+static void egalax_remove(struct hid_device *hdev)
+{
+	hid_hw_stop(hdev);
+	kfree(hid_get_drvdata(hdev));
+	hid_set_drvdata(hdev, NULL);
+}
+
+static const struct hid_device_id egalax_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_DWAV,
+			USB_DEVICE_ID_DWAV_EGALAX_MULTITOUCH) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, egalax_devices);
+
+static const struct hid_usage_id egalax_grabbed_usages[] = {
+	{ HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
+	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1}
+};
+
+static struct hid_driver egalax_driver = {
+	.name = "egalax-touch",
+	.id_table = egalax_devices,
+	.probe = egalax_probe,
+	.remove = egalax_remove,
+	.input_mapping = egalax_input_mapping,
+	.input_mapped = egalax_input_mapped,
+	.usage_table = egalax_grabbed_usages,
+	.event = egalax_event,
+};
+
+static int __init egalax_init(void)
+{
+	return hid_register_driver(&egalax_driver);
+}
+
+static void __exit egalax_exit(void)
+{
+	hid_unregister_driver(&egalax_driver);
+}
+
+module_init(egalax_init);
+module_exit(egalax_exit);
+