On 20/06/2016 17:09, Hans Verkuil wrote:

On 06/17/2016 04:16 PM, Nick Dyer wrote:

quoted

@@ -2325,11 +2344,20 @@ static int mxt_vidioc_querycap(struct file *file, void *priv,
 static int mxt_vidioc_enum_input(struct file *file, void *priv,
 				   struct v4l2_input *i)
 {
-	if (i->index > 0)
+	if (i->index >= MXT_V4L_INPUT_MAX)
 		return -EINVAL;
 
 	i->type = V4L2_INPUT_TYPE_TOUCH_SENSOR;
-	strlcpy(i->name, "Mutual References", sizeof(i->name));
+
+	switch (i->index) {
+	case MXT_V4L_INPUT_REFS:
+		strlcpy(i->name, "Mutual References", sizeof(i->name));
+		break;
+	case MXT_V4L_INPUT_DELTAS:
+		strlcpy(i->name, "Mutual Deltas", sizeof(i->name));

I don't think this name is very clear. I have no idea how to interpret "Mutual"
in this context.

"Mutual" is a touch domain specific term, it means the delta value is for
the capacitance between the horizontal and vertical lines at a particular
"node" on the touchscreen matrix, see
https://en.wikipedia.org/wiki/Touchscreen#Mutual_capacitance

I'll put in a comment.

quoted

+		break;
+	}
+
 	return 0;
 }
 

@@ -2337,12 +2365,16 @@ static int mxt_set_input(struct mxt_data *data, unsigned int i)
 {
 	struct v4l2_pix_format *f = &data->dbg.format;
 
-	if (i > 0)
+	if (i >= MXT_V4L_INPUT_MAX)
 		return -EINVAL;
 
+	if (i == MXT_V4L_INPUT_DELTAS)
+		f->pixelformat = V4L2_PIX_FMT_YS16;
+	else
+		f->pixelformat = V4L2_PIX_FMT_Y16;

You probably need a V4L2_TOUCH_FMT_U16 or something for this as well. It certainly
needs to be documented.

OK, will change this.