HID: multitouch: create sysfs attribute to control quirks from user-space

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

2 files changed, 68 insertions, 18 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-hid-multitouch b/Documentation/ABI/testing/sysfs-driver-hid-multitouch
new file mode 100644
index 00000000000..f79839d1af3
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-hid-multitouch
@@ -0,0 +1,9 @@
+What:           /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/<hid-bus>:<vendor-id>:<product-id>.<num>/quirks
+Date:           November 2011
+Contact:        Benjamin Tissoires <benjamin.tissoires@gmail.com>
+Description:    The integer value of this attribute corresponds to the
+                quirks actually in place to handle the device's protocol.
+                When read, this attribute returns the current settings (see
+                MT_QUIRKS_* in hid-multitouch.c).
+                When written this attribute change on the fly the quirks, then
+                the protocol to handle the device.
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index a59d939dd16..a51e62efbac 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -60,9 +60,19 @@ struct mt_slot {
         bool seen_in_this_frame;/* has this slot been updated */
 };
 
+struct mt_class {
+        __s32 name;     /* MT_CLS */
+        __s32 quirks;
+        __s32 sn_move;  /* Signal/noise ratio for move events */
+        __s32 sn_width; /* Signal/noise ratio for width events */
+        __s32 sn_height;        /* Signal/noise ratio for height events */
+        __s32 sn_pressure;      /* Signal/noise ratio for pressure events */
+        __u8 maxcontacts;
+};
+
 struct mt_device {
         struct mt_slot curdata; /* placeholder of incoming data */
-        struct mt_class *mtclass;       /* our mt device class */
+        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 */
         int last_mt_collection; /* last known mt-related collection */
@@ -74,16 +84,6 @@ struct mt_device {
         struct mt_slot *slots;
 };
 
-struct mt_class {
-        __s32 name;     /* MT_CLS */
-        __s32 quirks;
-        __s32 sn_move;  /* Signal/noise ratio for move events */
-        __s32 sn_width; /* Signal/noise ratio for width events */
-        __s32 sn_height;        /* Signal/noise ratio for height events */
-        __s32 sn_pressure;      /* Signal/noise ratio for pressure events */
-        __u8 maxcontacts;
-};
-
 /* classes of device behavior */
 #define MT_CLS_DEFAULT                          0x0001
 
@@ -181,6 +181,44 @@ struct mt_class mt_classes[] = {
         { }
 };
 
+static ssize_t mt_show_quirks(struct device *dev,
+                           struct device_attribute *attr,
+                           char *buf)
+{
+        struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+        struct mt_device *td = hid_get_drvdata(hdev);
+
+        return sprintf(buf, "%u\n", td->mtclass.quirks);
+}
+
+static ssize_t mt_set_quirks(struct device *dev,
+                          struct device_attribute *attr,
+                          const char *buf, size_t count)
+{
+        struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+        struct mt_device *td = hid_get_drvdata(hdev);
+
+        unsigned long val;
+
+        if (kstrtoul(buf, 0, &val))
+                return -EINVAL;
+
+        td->mtclass.quirks = val;
+
+        return count;
+}
+
+static DEVICE_ATTR(quirks, S_IWUSR | S_IRUGO, mt_show_quirks, mt_set_quirks);
+
+static struct attribute *sysfs_attrs[] = {
+        &dev_attr_quirks.attr,
+        NULL
+};
+
+static struct attribute_group mt_attribute_group = {
+        .attrs = sysfs_attrs
+};
+
 static void mt_feature_mapping(struct hid_device *hdev,
                 struct hid_field *field, struct hid_usage *usage)
 {
@@ -192,9 +230,9 @@ static void mt_feature_mapping(struct hid_device *hdev,
                 break;
         case HID_DG_CONTACTMAX:
                 td->maxcontacts = field->value[0];
-                if (td->mtclass->maxcontacts)
+                if (td->mtclass.maxcontacts)
                         /* check if the maxcontacts is given by the class */
-                        td->maxcontacts = td->mtclass->maxcontacts;
+                        td->maxcontacts = td->mtclass.maxcontacts;
 
                 break;
         }
@@ -214,7 +252,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
                 unsigned long **bit, int *max)
 {
         struct mt_device *td = hid_get_drvdata(hdev);
-        struct mt_class *cls = td->mtclass;
+        struct mt_class *cls = &td->mtclass;
         __s32 quirks = cls->quirks;
 
         /* Only map fields from TouchScreen or TouchPad collections.
@@ -363,7 +401,7 @@ static int mt_input_mapped(struct hid_device *hdev, struct hid_input *hi,
 
 static int mt_compute_slot(struct mt_device *td)
 {
-        __s32 quirks = td->mtclass->quirks;
+        __s32 quirks = td->mtclass.quirks;
 
         if (quirks & MT_QUIRK_SLOT_IS_CONTACTID)
                 return td->curdata.contactid;
@@ -407,7 +445,7 @@ static void mt_emit_event(struct mt_device *td, struct input_dev *input)
 
         for (i = 0; i < td->maxcontacts; ++i) {
                 struct mt_slot *s = &(td->slots[i]);
-                if ((td->mtclass->quirks & MT_QUIRK_NOT_SEEN_MEANS_UP) &&
+                if ((td->mtclass.quirks & MT_QUIRK_NOT_SEEN_MEANS_UP) &&
                         !s->seen_in_this_frame) {
                         s->touch_state = false;
                 }
@@ -444,7 +482,7 @@ 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);
-        __s32 quirks = td->mtclass->quirks;
+        __s32 quirks = td->mtclass.quirks;
 
         if (hid->claimed & HID_CLAIMED_INPUT && td->slots) {
                 switch (usage->hid) {
@@ -552,7 +590,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
                 dev_err(&hdev->dev, "cannot allocate multitouch data\n");
                 return -ENOMEM;
         }
-        td->mtclass = mtclass;
+        td->mtclass = *mtclass;
         td->inputmode = -1;
         td->last_mt_collection = -1;
         hid_set_drvdata(hdev, td);
@@ -574,6 +612,8 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
                 goto fail;
         }
 
+        ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
+
         mt_set_input_mode(hdev);
 
         return 0;
@@ -594,6 +634,7 @@ static int mt_reset_resume(struct hid_device *hdev)
 static void mt_remove(struct hid_device *hdev)
 {
         struct mt_device *td = hid_get_drvdata(hdev);
+        sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
         hid_hw_stop(hdev);
         kfree(td->slots);
         kfree(td);