Merge branches 'device-groups', 'logitech' and 'multitouch' into for-linus

drivers/hid/hid-lg.c

@@ -109,23 +109,23 @@ static __u8 dfp_rdesc_fixed[] = {
 static __u8 *lg_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 		unsigned int *rsize)
 {
-	unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
+	struct lg_drv_data *drv_data = (struct lg_drv_data *)hid_get_drvdata(hdev);
 
-	if ((quirks & LG_RDESC) && *rsize >= 90 && rdesc[83] == 0x26 &&
+	if ((drv_data->quirks & LG_RDESC) && *rsize >= 90 && rdesc[83] == 0x26 &&
 			rdesc[84] == 0x8c && rdesc[85] == 0x02) {
 		hid_info(hdev,
 			 "fixing up Logitech keyboard report descriptor\n");
 		rdesc[84] = rdesc[89] = 0x4d;
 		rdesc[85] = rdesc[90] = 0x10;
 	}
-	if ((quirks & LG_RDESC_REL_ABS) && *rsize >= 50 &&
+	if ((drv_data->quirks & LG_RDESC_REL_ABS) && *rsize >= 50 &&
 			rdesc[32] == 0x81 && rdesc[33] == 0x06 &&
 			rdesc[49] == 0x81 && rdesc[50] == 0x06) {
 		hid_info(hdev,
 			 "fixing up rel/abs in Logitech report descriptor\n");
 		rdesc[33] = rdesc[50] = 0x02;
 	}
-	if ((quirks & LG_FF4) && *rsize >= 101 &&
+	if ((drv_data->quirks & LG_FF4) && *rsize >= 101 &&
 			rdesc[41] == 0x95 && rdesc[42] == 0x0B &&
 			rdesc[47] == 0x05 && rdesc[48] == 0x09) {
 		hid_info(hdev, "fixing up Logitech Speed Force Wireless button descriptor\n");
@@ -278,7 +278,7 @@ static int lg_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 		  0,  0,  0,  0,  0,183,184,185,186,187,
 		188,189,190,191,192,193,194,  0,  0,  0
 	};
-	unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
+	struct lg_drv_data *drv_data = (struct lg_drv_data *)hid_get_drvdata(hdev);
 	unsigned int hid = usage->hid;
 
 	if (hdev->product == USB_DEVICE_ID_LOGITECH_RECEIVER &&
@@ -289,7 +289,7 @@ static int lg_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 			lg_dinovo_mapping(hi, usage, bit, max))
 		return 1;
 
-	if ((quirks & LG_WIRELESS) && lg_wireless_mapping(hi, usage, bit, max))
+	if ((drv_data->quirks & LG_WIRELESS) && lg_wireless_mapping(hi, usage, bit, max))
 		return 1;
 
 	if ((hid & HID_USAGE_PAGE) != HID_UP_BUTTON)
@@ -299,11 +299,11 @@ static int lg_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 
 	/* Special handling for Logitech Cordless Desktop */
 	if (field->application == HID_GD_MOUSE) {
-		if ((quirks & LG_IGNORE_DOUBLED_WHEEL) &&
+		if ((drv_data->quirks & LG_IGNORE_DOUBLED_WHEEL) &&
 				(hid == 7 || hid == 8))
 			return -1;
 	} else {
-		if ((quirks & LG_EXPANDED_KEYMAP) &&
+		if ((drv_data->quirks & LG_EXPANDED_KEYMAP) &&
 				hid < ARRAY_SIZE(e_keymap) &&
 				e_keymap[hid] != 0) {
 			hid_map_usage(hi, usage, bit, max, EV_KEY,
@@ -319,13 +319,13 @@ static int lg_input_mapped(struct hid_device *hdev, struct hid_input *hi,
 		struct hid_field *field, struct hid_usage *usage,
 		unsigned long **bit, int *max)
 {
-	unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
+	struct lg_drv_data *drv_data = (struct lg_drv_data *)hid_get_drvdata(hdev);
 
-	if ((quirks & LG_BAD_RELATIVE_KEYS) && usage->type == EV_KEY &&
+	if ((drv_data->quirks & LG_BAD_RELATIVE_KEYS) && usage->type == EV_KEY &&
 			(field->flags & HID_MAIN_ITEM_RELATIVE))
 		field->flags &= ~HID_MAIN_ITEM_RELATIVE;
 
-	if ((quirks & LG_DUPLICATE_USAGES) && (usage->type == EV_KEY ||
+	if ((drv_data->quirks & LG_DUPLICATE_USAGES) && (usage->type == EV_KEY ||
 			 usage->type == EV_REL || usage->type == EV_ABS))
 		clear_bit(usage->code, *bit);
 
@@ -335,9 +335,9 @@ static int lg_input_mapped(struct hid_device *hdev, struct hid_input *hi,
 static int lg_event(struct hid_device *hdev, struct hid_field *field,
 		struct hid_usage *usage, __s32 value)
 {
-	unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
+	struct lg_drv_data *drv_data = (struct lg_drv_data *)hid_get_drvdata(hdev);
 
-	if ((quirks & LG_INVERT_HWHEEL) && usage->code == REL_HWHEEL) {
+	if ((drv_data->quirks & LG_INVERT_HWHEEL) && usage->code == REL_HWHEEL) {
 		input_event(field->hidinput->input, usage->type, usage->code,
 				-value);
 		return 1;
@@ -348,13 +348,20 @@ static int lg_event(struct hid_device *hdev, struct hid_field *field,
 
 static int lg_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
-	unsigned long quirks = id->driver_data;
 	unsigned int connect_mask = HID_CONNECT_DEFAULT;
+	struct lg_drv_data *drv_data;
 	int ret;
 
-	hid_set_drvdata(hdev, (void *)quirks);
+	drv_data = kzalloc(sizeof(struct lg_drv_data), GFP_KERNEL);
+	if (!drv_data) {
+		hid_err(hdev, "Insufficient memory, cannot allocate driver data\n");
+		return -ENOMEM;
+	}
+	drv_data->quirks = id->driver_data;
+	
+	hid_set_drvdata(hdev, (void *)drv_data);
 
-	if (quirks & LG_NOGET)
+	if (drv_data->quirks & LG_NOGET)
 		hdev->quirks |= HID_QUIRK_NOGET;
 
 	ret = hid_parse(hdev);
@@ -363,7 +370,7 @@ static int lg_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		goto err_free;
 	}
 
-	if (quirks & (LG_FF | LG_FF2 | LG_FF3 | LG_FF4))
+	if (drv_data->quirks & (LG_FF | LG_FF2 | LG_FF3 | LG_FF4))
 		connect_mask &= ~HID_CONNECT_FF;
 
 	ret = hid_hw_start(hdev, connect_mask);
@@ -392,27 +399,29 @@ static int lg_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		}
 	}
 
-	if (quirks & LG_FF)
+	if (drv_data->quirks & LG_FF)
 		lgff_init(hdev);
-	if (quirks & LG_FF2)
+	if (drv_data->quirks & LG_FF2)
 		lg2ff_init(hdev);
-	if (quirks & LG_FF3)
+	if (drv_data->quirks & LG_FF3)
 		lg3ff_init(hdev);
-	if (quirks & LG_FF4)
+	if (drv_data->quirks & LG_FF4)
 		lg4ff_init(hdev);
 
 	return 0;
 err_free:
+	kfree(drv_data);
 	return ret;
 }
 
 static void lg_remove(struct hid_device *hdev)
 {
-	unsigned long quirks = (unsigned long)hid_get_drvdata(hdev);
-	if(quirks & LG_FF4)
+	struct lg_drv_data *drv_data = (struct lg_drv_data *)hid_get_drvdata(hdev);
+	if (drv_data->quirks & LG_FF4)
 		lg4ff_deinit(hdev);
 
 	hid_hw_stop(hdev);
+	kfree(drv_data);
 }
 
 static const struct hid_device_id lg_devices[] = {

drivers/hid/hid-lg.h

 #ifndef __HID_LG_H
 #define __HID_LG_H
 
+struct lg_drv_data {
+	unsigned long quirks;
+	void *device_props;	/* Device specific properties */
+};
+
 #ifdef CONFIG_LOGITECH_FF
 int lgff_init(struct hid_device *hdev);
 #else

drivers/hid/hid-lg4ff.c

 /*
- *  Force feedback support for Logitech Speed Force Wireless
+ *  Force feedback support for Logitech Gaming Wheels
  *
- *  http://wiibrew.org/wiki/Logitech_USB_steering_wheel
+ *  Including G27, G25, DFP, DFGT, FFEX, Momo, Momo2 &
+ *  Speed Force Wireless (WiiWheel)
  *
  *  Copyright (c) 2010 Simon Wood <simon@mungewell.org>
  */
@@ -51,20 +52,18 @@ static ssize_t lg4ff_range_store(struct device *dev, struct device_attribute *at
 
 static DEVICE_ATTR(range, S_IRWXU | S_IRWXG | S_IRWXO, lg4ff_range_show, lg4ff_range_store);
 
-static bool list_inited;
-
 struct lg4ff_device_entry {
-	char  *device_id;	/* Use name in respective kobject structure's address as the ID */
 	__u16 range;
 	__u16 min_range;
 	__u16 max_range;
-	__u8  leds;
+#ifdef CONFIG_LEDS_CLASS
+	__u8  led_state;
+	struct led_classdev *led[5];
+#endif
 	struct list_head list;
 	void (*set_range)(struct hid_device *hid, u16 range);
 };
 
-static struct lg4ff_device_entry device_list;
-
 static const signed short lg4ff_wheel_effects[] = {
 	FF_CONSTANT,
 	FF_AUTOCENTER,
@@ -285,18 +284,20 @@ static void hid_lg4ff_switch_native(struct hid_device *hid, const struct lg4ff_n
 /* Read current range and display it in terminal */
 static ssize_t lg4ff_range_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
-	struct lg4ff_device_entry *uninitialized_var(entry);
-	struct list_head *h;
 	struct hid_device *hid = to_hid_device(dev);
+	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
 	size_t count;
 
-	list_for_each(h, &device_list.list) {
-		entry = list_entry(h, struct lg4ff_device_entry, list);
-		if (strcmp(entry->device_id, (&hid->dev)->kobj.name) == 0)
-			break;
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Private driver data not found!\n");
+		return 0;
 	}
-	if (h == &device_list.list) {
-		dbg_hid("Device not found!");
+
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Device properties not found!\n");
 		return 0;
 	}
 
@@ -308,19 +309,21 @@ static ssize_t lg4ff_range_show(struct device *dev, struct device_attribute *att
  * according to the type of the wheel */
 static ssize_t lg4ff_range_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 {
-	struct lg4ff_device_entry *uninitialized_var(entry);
-	struct list_head *h;
 	struct hid_device *hid = to_hid_device(dev);
+	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
 	__u16 range = simple_strtoul(buf, NULL, 10);
 
-	list_for_each(h, &device_list.list) {
-		entry = list_entry(h, struct lg4ff_device_entry, list);
-		if (strcmp(entry->device_id, (&hid->dev)->kobj.name) == 0)
-			break;
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Private driver data not found!\n");
+		return 0;
 	}
-	if (h == &device_list.list) {
-		dbg_hid("Device not found!");
-		return count;
+
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Device properties not found!\n");
+		return 0;
 	}
 
 	if (range == 0)
@@ -336,6 +339,88 @@ static ssize_t lg4ff_range_store(struct device *dev, struct device_attribute *at
 	return count;
 }
 
+#ifdef CONFIG_LEDS_CLASS
+static void lg4ff_set_leds(struct hid_device *hid, __u8 leds)
+{
+	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
+
+	report->field[0]->value[0] = 0xf8;
+	report->field[0]->value[1] = 0x12;
+	report->field[0]->value[2] = leds;
+	report->field[0]->value[3] = 0x00;
+	report->field[0]->value[4] = 0x00;
+	report->field[0]->value[5] = 0x00;
+	report->field[0]->value[6] = 0x00;
+	usbhid_submit_report(hid, report, USB_DIR_OUT);
+}
+
+static void lg4ff_led_set_brightness(struct led_classdev *led_cdev,
+			enum led_brightness value)
+{
+	struct device *dev = led_cdev->dev->parent;
+	struct hid_device *hid = container_of(dev, struct hid_device, dev);
+	struct lg_drv_data *drv_data = (struct lg_drv_data *)hid_get_drvdata(hid);
+	struct lg4ff_device_entry *entry;
+	int i, state = 0;
+
+	if (!drv_data) {
+		hid_err(hid, "Device data not found.");
+		return;
+	}
+
+	entry = (struct lg4ff_device_entry *)drv_data->device_props;
+
+	if (!entry) {
+		hid_err(hid, "Device properties not found.");
+		return;
+	}
+
+	for (i = 0; i < 5; i++) {
+		if (led_cdev != entry->led[i])
+			continue;
+		state = (entry->led_state >> i) & 1;
+		if (value == LED_OFF && state) {
+			entry->led_state &= ~(1 << i);
+			lg4ff_set_leds(hid, entry->led_state);
+		} else if (value != LED_OFF && !state) {
+			entry->led_state |= 1 << i;
+			lg4ff_set_leds(hid, entry->led_state);
+		}
+		break;
+	}
+}
+
+static enum led_brightness lg4ff_led_get_brightness(struct led_classdev *led_cdev)
+{
+	struct device *dev = led_cdev->dev->parent;
+	struct hid_device *hid = container_of(dev, struct hid_device, dev);
+	struct lg_drv_data *drv_data = (struct lg_drv_data *)hid_get_drvdata(hid);
+	struct lg4ff_device_entry *entry;
+	int i, value = 0;
+
+	if (!drv_data) {
+		hid_err(hid, "Device data not found.");
+		return LED_OFF;
+	}
+
+	entry = (struct lg4ff_device_entry *)drv_data->device_props;
+
+	if (!entry) {
+		hid_err(hid, "Device properties not found.");
+		return LED_OFF;
+	}
+
+	for (i = 0; i < 5; i++)
+		if (led_cdev == entry->led[i]) {
+			value = (entry->led_state >> i) & 1;
+			break;
+		}
+
+	return value ? LED_FULL : LED_OFF;
+}
+#endif
+
 int lg4ff_init(struct hid_device *hid)
 {
 	struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
@@ -344,6 +429,7 @@ int lg4ff_init(struct hid_device *hid)
 	struct hid_report *report;
 	struct hid_field *field;
 	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
 	struct usb_device_descriptor *udesc;
 	int error, i, j;
 	__u16 bcdDevice, rev_maj, rev_min;
@@ -423,28 +509,24 @@ int lg4ff_init(struct hid_device *hid)
 		dev->ff->set_autocenter(dev, 0);
 	}
 
-		/* Initialize device_list if this is the first device to handle by lg4ff */
-	if (!list_inited) {
-		INIT_LIST_HEAD(&device_list.list);
-		list_inited = 1;
+	/* Get private driver data */
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Cannot add device, private driver data not allocated\n");
+		return -1;
 	}
 
-	/* Add the device to device_list */
+	/* Initialize device properties */
 	entry = kzalloc(sizeof(struct lg4ff_device_entry), GFP_KERNEL);
 	if (!entry) {
-		hid_err(hid, "Cannot add device, insufficient memory.\n");
-		return -ENOMEM;
-	}
-	entry->device_id = kstrdup((&hid->dev)->kobj.name, GFP_KERNEL);
-	if (!entry->device_id) {
-		hid_err(hid, "Cannot set device_id, insufficient memory.\n");
-		kfree(entry);
+		hid_err(hid, "Cannot add device, insufficient memory to allocate device properties.\n");
 		return -ENOMEM;
 	}
+	drv_data->device_props = entry;
+
 	entry->min_range = lg4ff_devices[i].min_range;
 	entry->max_range = lg4ff_devices[i].max_range;
 	entry->set_range = lg4ff_devices[i].set_range;
-	list_add(&entry->list, &device_list.list);
 
 	/* Create sysfs interface */
 	error = device_create_file(&hid->dev, &dev_attr_range);
@@ -457,32 +539,100 @@ int lg4ff_init(struct hid_device *hid)
 	if (entry->set_range != NULL)
 		entry->set_range(hid, entry->range);
 
-	hid_info(hid, "Force feedback for Logitech Speed Force Wireless by Simon Wood <simon@mungewell.org>\n");
+#ifdef CONFIG_LEDS_CLASS
+	/* register led subsystem - G27 only */
+	entry->led_state = 0;
+	for (j = 0; j < 5; j++)
+		entry->led[j] = NULL;
+
+	if (lg4ff_devices[i].product_id == USB_DEVICE_ID_LOGITECH_G27_WHEEL) {
+		struct led_classdev *led;
+		size_t name_sz;
+		char *name;
+
+		lg4ff_set_leds(hid, 0);
+
+		name_sz = strlen(dev_name(&hid->dev)) + 8;
+
+		for (j = 0; j < 5; j++) {
+			led = kzalloc(sizeof(struct led_classdev)+name_sz, GFP_KERNEL);
+			if (!led) {
+				hid_err(hid, "can't allocate memory for LED %d\n", j);
+				goto err;
+			}
+
+			name = (void *)(&led[1]);
+			snprintf(name, name_sz, "%s::RPM%d", dev_name(&hid->dev), j+1);
+			led->name = name;
+			led->brightness = 0;
+			led->max_brightness = 1;
+			led->brightness_get = lg4ff_led_get_brightness;
+			led->brightness_set = lg4ff_led_set_brightness;
+
+			entry->led[j] = led;
+			error = led_classdev_register(&hid->dev, led);
+
+			if (error) {
+				hid_err(hid, "failed to register LED %d. Aborting.\n", j);
+err:
+				/* Deregister LEDs (if any) */
+				for (j = 0; j < 5; j++) {
+					led = entry->led[j];
+					entry->led[j] = NULL;
+					if (!led)
+						continue;
+					led_classdev_unregister(led);
+					kfree(led);
+				}
+				goto out;	/* Let the driver continue without LEDs */
+			}
+		}
+	}
+out:
+#endif
+	hid_info(hid, "Force feedback support for Logitech Gaming Wheels\n");
 	return 0;
 }
 
 int lg4ff_deinit(struct hid_device *hid)
 {
-	bool found = 0;
 	struct lg4ff_device_entry *entry;
-	struct list_head *h, *g;
-	list_for_each_safe(h, g, &device_list.list) {
-		entry = list_entry(h, struct lg4ff_device_entry, list);
-		if (strcmp(entry->device_id, (&hid->dev)->kobj.name) == 0) {
-			list_del(h);
-			kfree(entry->device_id);
-			kfree(entry);
-			found = 1;
-			break;
+	struct lg_drv_data *drv_data;
+
+	device_remove_file(&hid->dev, &dev_attr_range);
+
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Error while deinitializing device, no private driver data.\n");
+		return -1;
 	}
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Error while deinitializing device, no device properties data.\n");
+		return -1;
 	}
 
-	if (!found) {
-		dbg_hid("Device entry not found!\n");
-		return -1;
+#ifdef CONFIG_LEDS_CLASS
+	{
+		int j;
+		struct led_classdev *led;
+
+		/* Deregister LEDs (if any) */
+		for (j = 0; j < 5; j++) {
+
+			led = entry->led[j];
+			entry->led[j] = NULL;
+			if (!led)
+				continue;
+			led_classdev_unregister(led);
+			kfree(led);
+		}
 	}
+#endif
+
+	/* Deallocate memory */
+	kfree(entry);
 
-	device_remove_file(&hid->dev, &dev_attr_range);
 	dbg_hid("Device successfully unregistered\n");
 	return 0;
 }

drivers/hid/hid-multitouch.c

@@ -70,9 +70,16 @@ struct mt_class {
 	bool is_indirect;	/* true for touchpads */
 };
 
+struct mt_fields {
+	unsigned usages[HID_MAX_FIELDS];
+	unsigned int length;
+};
+
 struct mt_device {
 	struct mt_slot curdata;	/* placeholder of incoming data */
 	struct mt_class mtclass;	/* our mt device class */
+	struct mt_fields *fields;	/* temporary placeholder for storing the
+					   multitouch fields */
 	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 */
@@ -278,11 +285,15 @@ static void set_abs(struct input_dev *input, unsigned int code,
 	input_set_abs_params(input, code, fmin, fmax, fuzz, 0);
 }
 
-static void set_last_slot_field(struct hid_usage *usage, struct mt_device *td,
+static void mt_store_field(struct hid_usage *usage, struct mt_device *td,
 		struct hid_input *hi)
 {
-	if (!test_bit(usage->hid, hi->input->absbit))
-		td->last_slot_field = usage->hid;
+	struct mt_fields *f = td->fields;
+
+	if (f->length >= HID_MAX_FIELDS)
+		return;
+
+	f->usages[f->length++] = usage->hid;
 }
 
 static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
@@ -333,7 +344,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 				cls->sn_move);
 			/* touchscreen emulation */
 			set_abs(hi->input, ABS_X, field, cls->sn_move);
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
 		case HID_GD_Y:
@@ -343,7 +354,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 				cls->sn_move);
 			/* touchscreen emulation */
 			set_abs(hi->input, ABS_Y, field, cls->sn_move);
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
 		}
@@ -352,24 +363,24 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 	case HID_UP_DIGITIZER:
 		switch (usage->hid) {
 		case HID_DG_INRANGE:
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
 		case HID_DG_CONFIDENCE:
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			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);
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
 		case HID_DG_CONTACTID:
 			if (!td->maxcontacts)
 				td->maxcontacts = MT_DEFAULT_MAXCONTACT;
 			input_mt_init_slots(hi->input, td->maxcontacts);
-			td->last_slot_field = usage->hid;
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			td->touches_by_report++;
 			return 1;
@@ -378,7 +389,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 					EV_ABS, ABS_MT_TOUCH_MAJOR);
 			set_abs(hi->input, ABS_MT_TOUCH_MAJOR, field,
 				cls->sn_width);
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
 		case HID_DG_HEIGHT:
@@ -388,7 +399,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 				cls->sn_height);
 			input_set_abs_params(hi->input,
 					ABS_MT_ORIENTATION, 0, 1, 0, 0);
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
 		case HID_DG_TIPPRESSURE:
@@ -399,7 +410,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 			/* touchscreen emulation */
 			set_abs(hi->input, ABS_PRESSURE, field,
 				cls->sn_pressure);
-			set_last_slot_field(usage, td, hi);
+			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
 		case HID_DG_CONTACTCOUNT:
@@ -653,6 +664,16 @@ static void mt_post_parse_default_settings(struct mt_device *td)
 	td->mtclass.quirks = quirks;
 }
 
+static void mt_post_parse(struct mt_device *td)
+{
+	struct mt_fields *f = td->fields;
+
+	if (td->touches_by_report > 0) {
+		int field_count_per_touch = f->length / td->touches_by_report;
+		td->last_slot_field = f->usages[field_count_per_touch - 1];
+	}
+}
+
 static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	int ret, i;
@@ -683,6 +704,13 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	td->maxcontact_report_id = -1;
 	hid_set_drvdata(hdev, td);
 
+	td->fields = kzalloc(sizeof(struct mt_fields), GFP_KERNEL);
+	if (!td->fields) {
+		dev_err(&hdev->dev, "cannot allocate multitouch fields data\n");
+		ret = -ENOMEM;
+		goto fail;
+	}
+
 	ret = hid_parse(hdev);
 	if (ret != 0)
 		goto fail;
@@ -691,6 +719,8 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	if (ret)
 		goto fail;
 
+	mt_post_parse(td);
+
 	if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
 		mt_post_parse_default_settings(td);
 
@@ -708,9 +738,13 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	mt_set_maxcontacts(hdev);
 	mt_set_input_mode(hdev);
 
+	kfree(td->fields);
+	td->fields = NULL;
+
 	return 0;
 
 fail:
+	kfree(td->fields);
 	kfree(td);
 	return ret;
 }