HID: multitouch: fix LG Melfas touchscreen

The LG Melfas touchscreen has a bad firmware where it declares the Contact ID
field as constant while it shouldn't. This messes up the autodetection and the
reporting of the events by hid-multitouch given that hid-input ignores constant
fields.

The autodetection is simply worked around by manually adding the device to
hid_have_special_driver[].

The processing of the events requires either a report fixup, or some specific
case handling. Given that the report fixup would require to basically rewrite
all the report descriptor, I went for the programatic way of fixing that after
the report descriptors are loaded.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1416181
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index ea36b557d5eea87b27171937fe9bc05f680b15a8..1f6d0c0003815d97d6fc4f59d1ae41ede88fb74c 100644 (file)
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1933,6 +1933,7 @@ static const struct hid_device_id hid_have_special_driver[] = {
        { HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_CBTKBD) },
        { HID_USB_DEVICE(USB_VENDOR_ID_LENOVO, USB_DEVICE_ID_LENOVO_TPPRODOCK) },
 #endif
+       { HID_USB_DEVICE(USB_VENDOR_ID_LG, USB_DEVICE_ID_LG_MELFAS_MT) },
        { HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_MX3000_RECEIVER) },
        { HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_S510_RECEIVER) },
        { HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH, USB_DEVICE_ID_S510_RECEIVER_2) },

diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 350accfee8e85b2e545c0171f6582f4e62655b50..8943a58c626d36f6ae626dd84c2795e8615f56c1 100644 (file)
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -633,6 +633,7 @@
 
 #define USB_VENDOR_ID_LG               0x1fd2
 #define USB_DEVICE_ID_LG_MULTITOUCH    0x0064
+#define USB_DEVICE_ID_LG_MELFAS_MT     0x6007
 
 #define USB_VENDOR_ID_LOGITECH         0x046d
 #define USB_DEVICE_ID_LOGITECH_AUDIOHUB 0x0a0e

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 6dca668068440213d837f69c7763bddbe91e561b..692647485a53b3316ec442518b0b84648113dda9 100644 (file)
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -68,6 +68,7 @@ MODULE_LICENSE("GPL");
 #define MT_QUIRK_HOVERING              (1 << 11)
 #define MT_QUIRK_CONTACT_CNT_ACCURATE  (1 << 12)
 #define MT_QUIRK_FORCE_GET_FEATURE     (1 << 13)
+#define MT_QUIRK_FIX_CONST_CONTACT_ID  (1 << 14)
 
 #define MT_INPUTMODE_TOUCHSCREEN       0x02
 #define MT_INPUTMODE_TOUCHPAD          0x03
@@ -157,6 +158,7 @@ static void mt_post_parse(struct mt_device *td);
 #define MT_CLS_FLATFROG                                0x0107
 #define MT_CLS_GENERALTOUCH_TWOFINGERS         0x0108
 #define MT_CLS_GENERALTOUCH_PWT_TENFINGERS     0x0109
+#define MT_CLS_LG                              0x010a
 #define MT_CLS_VTL                             0x0110
 
 #define MT_DEFAULT_MAXCONTACT  10
@@ -263,6 +265,12 @@ static struct mt_class mt_classes[] = {
                .sn_move = 2048,
                .maxcontacts = 40,
        },
+       { .name = MT_CLS_LG,
+               .quirks = MT_QUIRK_ALWAYS_VALID |
+                       MT_QUIRK_FIX_CONST_CONTACT_ID |
+                       MT_QUIRK_IGNORE_DUPLICATES |
+                       MT_QUIRK_HOVERING |
+                       MT_QUIRK_CONTACT_CNT_ACCURATE },
        { .name = MT_CLS_VTL,
                .quirks = MT_QUIRK_ALWAYS_VALID |
                        MT_QUIRK_CONTACT_CNT_ACCURATE |
@@ -1078,6 +1086,34 @@ static int mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
        return 0;
 }
 
+static void mt_fix_const_field(struct hid_field *field, unsigned int usage)
+{
+       if (field->usage[0].hid != usage ||
+           !(field->flags & HID_MAIN_ITEM_CONSTANT))
+               return;
+
+       field->flags &= ~HID_MAIN_ITEM_CONSTANT;
+       field->flags |= HID_MAIN_ITEM_VARIABLE;
+}
+
+static void mt_fix_const_fields(struct hid_device *hdev, unsigned int usage)
+{
+       struct hid_report *report;
+       int i;
+
+       list_for_each_entry(report,
+                           &hdev->report_enum[HID_INPUT_REPORT].report_list,
+                           list) {
+
+               if (!report->maxfield)
+                       continue;
+
+               for (i = 0; i < report->maxfield; i++)
+                       if (report->field[i]->maxusage >= 1)
+                               mt_fix_const_field(report->field[i], usage);
+       }
+}
+
 static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
        int ret, i;
@@ -1151,6 +1187,9 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
        if (ret != 0)
                return ret;
 
+       if (mtclass->quirks & MT_QUIRK_FIX_CONST_CONTACT_ID)
+               mt_fix_const_fields(hdev, HID_DG_CONTACTID);
+
        ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
        if (ret)
                return ret;
@@ -1398,6 +1437,11 @@ static const struct hid_device_id mt_devices[] = {
                MT_USB_DEVICE(USB_VENDOR_ID_ILITEK,
                        USB_DEVICE_ID_ILITEK_MULTITOUCH) },
 
+       /* LG Melfas panel */
+       { .driver_data = MT_CLS_LG,
+               HID_USB_DEVICE(USB_VENDOR_ID_LG,
+                       USB_DEVICE_ID_LG_MELFAS_MT) },
+
        /* MosArt panels */
        { .driver_data = MT_CLS_CONFIDENCE_MINUS_ONE,
                MT_USB_DEVICE(USB_VENDOR_ID_ASUS,