[PATCH] v4l: 850: update em2800 scaler code and comments based on info from empiatech

- Update em2800 scaler code and comments based on info from empiatech
Signed-off-by: Sascha Sommer <saschasommer@freenet.de>
Signed-off-by: Markus Rechberger <mrechberger@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/media/video/em28xx/em28xx-core.c

@@ -430,6 +430,11 @@ int em2820_capture_area_set(struct em2820 *dev, u8 hstart, u8 vstart,
 
 int em2820_scaler_set(struct em2820 *dev, u16 h, u16 v)
 {
+	u8 mode;
+	/* the em2800 scaler only supports scaling down to 50% */
+	if(dev->is_em2800)
+		mode = (v ? 0x20 : 0x00) | (h ? 0x10 : 0x00);
+	else {
 		u8 buf[2];
 		buf[0] = h;
 		buf[1] = h >> 8;
@@ -437,23 +442,10 @@ int em2820_scaler_set(struct em2820 *dev, u16 h, u16 v)
 		buf[0] = v;
 		buf[1] = v >> 8;
 		em2820_write_regs(dev, VSCALELOW_REG, (char *)buf, 2);
-	if(dev->is_em2800){
-		/* FIXME */
-		/* random ratio scaling and 720x567 doesn't seem to work */
-		/* the maximum we can get is 640x480 with disabled scaler */
-		/* and norm_maxw set to 640 */
-		if(dev->width == 640 && dev->height == 480)
-			return em2820_write_regs(dev, COMPR_REG,"\x00",1);
-		if(dev->height > 288)
-			return em2820_write_regs(dev, COMPR_REG,"\x10",1);
-		if(dev->width > 360)
-			return em2820_write_regs(dev, COMPR_REG,"\x20",1);
-	}
-	/* when H and V mixershould be used? */
-	/*	return em2820_write_reg_bits(dev, COMPR_REG, (h ? 0x20 : 0x00) | (v ? 0x10 : 0x00), 0x30); */
 		/* it seems that both H and V scalers must be active to work correctly */
-	return em2820_write_reg_bits(dev, COMPR_REG, h
-			|| v ? 0x30 : 0x00, 0x30);
+		mode = (h || v)? 0x30: 0x00;
+	}
+	return em2820_write_reg_bits(dev, COMPR_REG, mode, 0x30);
 }
 
 /* FIXME: this only function read values from dev */

drivers/media/video/em28xx/em28xx-video.c

@@ -1308,14 +1308,18 @@ static int em2820_video_do_ioctl(struct inode *inode, struct file *filp,
 			if (width > maxw)
 				width = maxw;
 
-			/* FIXME*/
 			if(dev->is_em2800){
-				/* we only know how to scale to 50% */
+				/* the em2800 can only scale down to 50% */
 				if(height % (maxh / 2))
 					height=maxh;
 				if(width % (maxw / 2))
 					width=maxw;
-				/* larger resoltion don't seem to work either */
+				/* according to empiatech support */
+				/* the MaxPacketSize is to small to support */
+				/* framesizes larger than 640x480 @ 30 fps */
+				/* or 640x576 @ 25 fps. As this would cut */
+				/* of a part of the image we prefer */
+				/* 360x576 or 360x480 for now */
 				if(width == maxw && height == maxh)
 					width /= 2;
 			}