[media] solo6x10: Approximate frame intervals with non-standard denominator

Instead of falling back to 1/25 (PAL) or 1/30 (NTSC).
Signed-off-by: Ismael Luceno <ismael.luceno@corp.bluecherry.net>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/staging/media/solo6x10/solo6x10-v4l2-enc.c

@@ -996,12 +996,11 @@ static int solo_g_parm(struct file *file, void *priv,
 		       struct v4l2_streamparm *sp)
 {
 	struct solo_enc_dev *solo_enc = video_drvdata(file);
-	struct solo_dev *solo_dev = solo_enc->solo_dev;
 	struct v4l2_captureparm *cp = &sp->parm.capture;
 
 	cp->capability = V4L2_CAP_TIMEPERFRAME;
 	cp->timeperframe.numerator = solo_enc->interval;
-	cp->timeperframe.denominator = solo_dev->fps;
+	cp->timeperframe.denominator = solo_enc->solo_dev->fps;
 	cp->capturemode = 0;
 	/* XXX: Shouldn't we be able to get/set this from videobuf? */
 	cp->readbuffers = 2;
@@ -1009,36 +1008,29 @@ static int solo_g_parm(struct file *file, void *priv,
 	return 0;
 }
 
+static inline int calc_interval(u8 fps, u32 n, u32 d)
+{
+	if (!n || !d)
+		return 1;
+	if (d == fps)
+		return n;
+	n *= fps;
+	return min(15U, n / d + (n % d >= (fps >> 1)));
+}
+
 static int solo_s_parm(struct file *file, void *priv,
 		       struct v4l2_streamparm *sp)
 {
 	struct solo_enc_dev *solo_enc = video_drvdata(file);
-	struct solo_dev *solo_dev = solo_enc->solo_dev;
-	struct v4l2_captureparm *cp = &sp->parm.capture;
+	struct v4l2_fract *t = &sp->parm.capture.timeperframe;
+	u8 fps = solo_enc->solo_dev->fps;
 
 	if (vb2_is_streaming(&solo_enc->vidq))
 		return -EBUSY;
 
-	if ((cp->timeperframe.numerator == 0) ||
-	    (cp->timeperframe.denominator == 0)) {
-		/* reset framerate */
-		cp->timeperframe.numerator = 1;
-		cp->timeperframe.denominator = solo_dev->fps;
-	}
-
-	if (cp->timeperframe.denominator != solo_dev->fps)
-		cp->timeperframe.denominator = solo_dev->fps;
-
-	if (cp->timeperframe.numerator > 15)
-		cp->timeperframe.numerator = 15;
-
-	solo_enc->interval = cp->timeperframe.numerator;
-
-	cp->capability = V4L2_CAP_TIMEPERFRAME;
-	cp->readbuffers = 2;
-
+	solo_enc->interval = calc_interval(fps, t->numerator, t->denominator);
 	solo_update_mode(solo_enc);
-	return 0;
+	return solo_g_parm(file, priv, sp);
 }
 
 static long solo_enc_default(struct file *file, void *fh,