HID: hid-multitouch: support for PixCir-based panels

Created a driver for PixCir based dual-touch panels, including the one
in the Hanvon tablet.  This is done in a code structure aimed at unifying
support for several existing HID multitouch panels.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Stéphane Chatty <chatty@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 468 insertions, 0 deletions

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
new file mode 100644
index 000000000000..3b05dfe910bc
--- /dev/null
+++ b/drivers/hid/hid-multitouch.c
@@ -0,0 +1,468 @@
+/*
+ *  HID driver for multitouch panels
+ *
+ *  Copyright (c) 2010-2011 Stephane Chatty <chatty@enac.fr>
+ *  Copyright (c) 2010-2011 Benjamin Tissoires <benjamin.tissoires@gmail.com>
+ *  Copyright (c) 2010-2011 Ecole Nationale de l'Aviation Civile, France
+ *
+ */
+
+/*
+ * 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/slab.h>
+#include <linux/usb.h>
+#include <linux/input/mt.h>
+#include "usbhid/usbhid.h"
+
+
+MODULE_AUTHOR("Stephane Chatty <chatty@enac.fr>");
+MODULE_DESCRIPTION("HID multitouch panels");
+MODULE_LICENSE("GPL");
+
+#include "hid-ids.h"
+
+/* quirks to control the device */
+#define MT_QUIRK_NOT_SEEN_MEANS_UP	(1 << 0)
+#define MT_QUIRK_SLOT_IS_CONTACTID	(1 << 1)
+
+struct mt_slot {
+	__s32 x, y, p, w, h;
+	__s32 contactid;	/* the device ContactID assigned to this slot */
+	bool touch_state;	/* is the touch valid? */
+	bool seen_in_this_frame;/* has this slot been updated */
+};
+
+struct mt_device {
+	struct mt_slot curdata;	/* placeholder of incoming data */
+	struct mt_class *mtclass;	/* our mt device class */
+	unsigned last_field_index;	/* last field index of the report */
+	unsigned last_slot_field;	/* the last field of a slot */
+	__s8 inputmode;		/* InputMode HID feature, -1 if non-existent */
+	__u8 num_received;	/* how many contacts we received */
+	__u8 num_expected;	/* expected last contact index */
+	bool curvalid;		/* is the current contact valid? */
+	struct mt_slot slots[0];	/* first slot */
+};
+
+struct mt_class {
+	__s32 quirks;
+	__s32 sn_move;	/* Signal/noise ratio for move events */
+	__s32 sn_pressure;	/* Signal/noise ratio for pressure events */
+	__u8 maxcontacts;
+};
+
+/* classes of device behavior */
+#define MT_CLS_DEFAULT 0
+#define MT_CLS_DUAL1 1
+
+/*
+ * these device-dependent functions determine what slot corresponds
+ * to a valid contact that was just read.
+ */
+
+static int slot_is_contactid(struct mt_device *td)
+{
+	return td->curdata.contactid;
+}
+
+static int find_slot_from_contactid(struct mt_device *td)
+{
+	int i;
+	for (i = 0; i < td->mtclass->maxcontacts; ++i) {
+		if (td->slots[i].contactid == td->curdata.contactid &&
+			td->slots[i].touch_state)
+			return i;
+	}
+	for (i = 0; i < td->mtclass->maxcontacts; ++i) {
+		if (!td->slots[i].seen_in_this_frame &&
+			!td->slots[i].touch_state)
+			return i;
+	}
+	return -1;
+	/* should not occurs. If this happens that means
+	 * that the device sent more touches that it says
+	 * in the report descriptor. It is ignored then. */
+}
+
+struct mt_class mt_classes[] = {
+	{ 0, 0, 0, 10 },                             /* MT_CLS_DEFAULT */
+	{ MT_QUIRK_SLOT_IS_CONTACTID, 0, 0, 2 },     /* MT_CLS_DUAL1 */
+};
+
+static void mt_feature_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage)
+{
+	if (usage->hid == HID_DG_INPUTMODE) {
+		struct mt_device *td = hid_get_drvdata(hdev);
+		td->inputmode = field->report->id;
+	}
+}
+
+static void set_abs(struct input_dev *input, unsigned int code,
+		struct hid_field *field, int snratio)
+{
+	int fmin = field->logical_minimum;
+	int fmax = field->logical_maximum;
+	int fuzz = snratio ? (fmax - fmin) / snratio : 0;
+	input_set_abs_params(input, code, fmin, fmax, fuzz, 0);
+}
+
+static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	struct mt_device *td = hid_get_drvdata(hdev);
+	struct mt_class *cls = td->mtclass;
+	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);
+			set_abs(hi->input, ABS_MT_POSITION_X, field,
+				cls->sn_move);
+			/* touchscreen emulation */
+			set_abs(hi->input, ABS_X, field, cls->sn_move);
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_GD_Y:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_POSITION_Y);
+			set_abs(hi->input, ABS_MT_POSITION_Y, field,
+				cls->sn_move);
+			/* touchscreen emulation */
+			set_abs(hi->input, ABS_Y, field, cls->sn_move);
+			td->last_slot_field = usage->hid;
+			return 1;
+		}
+		return 0;
+
+	case HID_UP_DIGITIZER:
+		switch (usage->hid) {
+		case HID_DG_INRANGE:
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_DG_CONFIDENCE:
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_DG_TIPSWITCH:
+			hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
+			input_set_capability(hi->input, EV_KEY, BTN_TOUCH);
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_DG_CONTACTID:
+			input_mt_init_slots(hi->input,
+					td->mtclass->maxcontacts);
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_DG_WIDTH:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_TOUCH_MAJOR);
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_DG_HEIGHT:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_TOUCH_MINOR);
+			field->logical_maximum = 1;
+			field->logical_minimum = 1;
+			set_abs(hi->input, ABS_MT_ORIENTATION, field, 0);
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_DG_TIPPRESSURE:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_PRESSURE);
+			set_abs(hi->input, ABS_MT_PRESSURE, field,
+				cls->sn_pressure);
+			/* touchscreen emulation */
+			set_abs(hi->input, ABS_PRESSURE, field,
+				cls->sn_pressure);
+			td->last_slot_field = usage->hid;
+			return 1;
+		case HID_DG_CONTACTCOUNT:
+			td->last_field_index = field->report->maxfield - 1;
+			return 1;
+		case HID_DG_CONTACTMAX:
+			/* we don't set td->last_slot_field as contactcount and
+			 * contact max are global to the report */
+			return -1;
+		}
+		/* let hid-input decide for the others */
+		return 0;
+
+	case 0xff000000:
+		/* we do not want to map these: no input-oriented meaning */
+		return -1;
+	}
+
+	return 0;
+}
+
+static int mt_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)
+		set_bit(usage->type, hi->input->evbit);
+
+	return -1;
+}
+
+static int mt_compute_slot(struct mt_device *td)
+{
+	struct mt_class *cls = td->mtclass;
+
+	if (cls->quirks & MT_QUIRK_SLOT_IS_CONTACTID)
+		return slot_is_contactid(td);
+
+	return find_slot_from_contactid(td);
+}
+
+/*
+ * this function is called when a whole contact has been processed,
+ * so that it can assign it to a slot and store the data there
+ */
+static void mt_complete_slot(struct mt_device *td)
+{
+	if (td->curvalid) {
+		struct mt_slot *slot;
+		int slotnum = mt_compute_slot(td);
+
+		if (slotnum >= 0 && slotnum < td->mtclass->maxcontacts) {
+			slot = td->slots + slotnum;
+
+			memcpy(slot, &(td->curdata), sizeof(struct mt_slot));
+			slot->seen_in_this_frame = true;
+		}
+	}
+	td->num_received++;
+}
+
+
+/*
+ * this function is called when a whole packet has been received and processed,
+ * so that it can decide what to send to the input layer.
+ */
+static void mt_emit_event(struct mt_device *td, struct input_dev *input)
+{
+	int i;
+
+	for (i = 0; i < td->mtclass->maxcontacts; ++i) {
+		struct mt_slot *s = &(td->slots[i]);
+		if ((td->mtclass->quirks & MT_QUIRK_NOT_SEEN_MEANS_UP) &&
+			!s->seen_in_this_frame) {
+			/*
+			 * this slot does not contain useful data,
+			 * notify its closure
+			 */
+			s->touch_state = false;
+		}
+
+		input_mt_slot(input, i);
+		input_mt_report_slot_state(input, MT_TOOL_FINGER,
+			s->touch_state);
+		input_event(input, EV_ABS, ABS_MT_POSITION_X, s->x);
+		input_event(input, EV_ABS, ABS_MT_POSITION_Y, s->y);
+		input_event(input, EV_ABS, ABS_MT_PRESSURE, s->p);
+		input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, s->w);
+		input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, s->h);
+		s->seen_in_this_frame = false;
+
+	}
+
+	input_mt_report_pointer_emulation(input, true);
+	input_sync(input);
+	td->num_received = 0;
+}
+
+
+
+static int mt_event(struct hid_device *hid, struct hid_field *field,
+				struct hid_usage *usage, __s32 value)
+{
+	struct mt_device *td = hid_get_drvdata(hid);
+
+	if (hid->claimed & HID_CLAIMED_INPUT) {
+		switch (usage->hid) {
+		case HID_DG_INRANGE:
+			break;
+		case HID_DG_TIPSWITCH:
+			td->curvalid = value;
+			td->curdata.touch_state = value;
+			break;
+		case HID_DG_CONFIDENCE:
+			break;
+		case HID_DG_CONTACTID:
+			td->curdata.contactid = value;
+			break;
+		case HID_DG_TIPPRESSURE:
+			td->curdata.p = value;
+			break;
+		case HID_GD_X:
+			td->curdata.x = value;
+			break;
+		case HID_GD_Y:
+			td->curdata.y = value;
+			break;
+		case HID_DG_WIDTH:
+			td->curdata.w = value;
+			break;
+		case HID_DG_HEIGHT:
+			td->curdata.h = value;
+			break;
+		case HID_DG_CONTACTCOUNT:
+			/*
+			 * We must not overwrite the previous value (some
+			 * devices send one sequence splitted over several
+			 * messages)
+			 */
+			if (value)
+				td->num_expected = value - 1;
+			break;
+
+		default:
+			/* fallback to the generic hidinput handling */
+			return 0;
+		}
+	}
+
+	if (usage->hid == td->last_slot_field)
+		mt_complete_slot(td);
+
+	if (field->index == td->last_field_index
+		&& td->num_received > td->num_expected)
+		mt_emit_event(td, field->hidinput->input);
+
+	/* 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 void mt_set_input_mode(struct hid_device *hdev)
+{
+	struct mt_device *td = hid_get_drvdata(hdev);
+	struct hid_report *r;
+	struct hid_report_enum *re;
+
+	if (td->inputmode < 0)
+		return;
+
+	re = &(hdev->report_enum[HID_FEATURE_REPORT]);
+	r = re->report_id_hash[td->inputmode];
+	if (r) {
+		r->field[0]->value[0] = 0x02;
+		usbhid_submit_report(hdev, r, USB_DIR_OUT);
+	}
+}
+
+static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+	struct mt_device *td;
+	struct mt_class *mtclass = mt_classes + id->driver_data;
+
+	/* This allows the driver to correctly support devices
+	 * that emit events over several HID messages.
+	 */
+	hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
+
+	td = kzalloc(sizeof(struct mt_device) +
+				mtclass->maxcontacts * sizeof(struct mt_slot),
+				GFP_KERNEL);
+	if (!td) {
+		dev_err(&hdev->dev, "cannot allocate multitouch data\n");
+		return -ENOMEM;
+	}
+	td->mtclass = mtclass;
+	td->inputmode = -1;
+	hid_set_drvdata(hdev, td);
+
+	ret = hid_parse(hdev);
+	if (ret != 0)
+		goto fail;
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret != 0)
+		goto fail;
+
+	mt_set_input_mode(hdev);
+
+	return 0;
+
+fail:
+	kfree(td);
+	return ret;
+}
+
+#ifdef CONFIG_PM
+static int mt_reset_resume(struct hid_device *hdev)
+{
+	mt_set_input_mode(hdev);
+	return 0;
+}
+#endif
+
+static void mt_remove(struct hid_device *hdev)
+{
+	struct mt_device *td = hid_get_drvdata(hdev);
+	hid_hw_stop(hdev);
+	kfree(td);
+	hid_set_drvdata(hdev, NULL);
+}
+
+static const struct hid_device_id mt_devices[] = {
+
+	/* PixCir-based panels */
+	{ .driver_data = MT_CLS_DUAL1,
+		HID_USB_DEVICE(USB_VENDOR_ID_HANVON,
+			USB_DEVICE_ID_HANVON_MULTITOUCH) },
+	{ .driver_data = MT_CLS_DUAL1,
+		HID_USB_DEVICE(USB_VENDOR_ID_CANDO,
+			USB_DEVICE_ID_CANDO_PIXCIR_MULTI_TOUCH) },
+
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, mt_devices);
+
+static const struct hid_usage_id mt_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 mt_driver = {
+	.name = "hid-multitouch",
+	.id_table = mt_devices,
+	.probe = mt_probe,
+	.remove = mt_remove,
+	.input_mapping = mt_input_mapping,
+	.input_mapped = mt_input_mapped,
+	.feature_mapping = mt_feature_mapping,
+	.usage_table = mt_grabbed_usages,
+	.event = mt_event,
+#ifdef CONFIG_PM
+	.reset_resume = mt_reset_resume,
+#endif
+};
+
+static int __init mt_init(void)
+{
+	return hid_register_driver(&mt_driver);
+}
+
+static void __exit mt_exit(void)
+{
+	hid_unregister_driver(&mt_driver);
+}
+
+module_init(mt_init);
+module_exit(mt_exit);