[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>

2 files changed, 22 insertions, 26 deletions

diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c
index ba2d986c6dfc..263b6c91adb5 100644
--- a/drivers/media/video/em28xx/em28xx-core.c
+++ b/drivers/media/video/em28xx/em28xx-core.c
@@ -430,30 +430,22 @@ int em2820_capture_area_set(struct em2820 *dev, u8 hstart, u8 vstart,
 
 int em2820_scaler_set(struct em2820 *dev, u16 h, u16 v)
 {
-        u8 buf[2];
-        buf[0] = h;
-        buf[1] = h >> 8;
-        em2820_write_regs(dev, HSCALELOW_REG, (char *)buf, 2);
-        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);
+        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;
+                em2820_write_regs(dev, HSCALELOW_REG, (char *)buf, 2);
+                buf[0] = v;
+                buf[1] = v >> 8;
+                em2820_write_regs(dev, VSCALELOW_REG, (char *)buf, 2);
+                /* it seems that both H and V scalers must be active to work correctly */
+                mode = (h || v)? 0x30: 0x00;
         }
-        /* 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);
+        return em2820_write_reg_bits(dev, COMPR_REG, mode, 0x30);
 }
 
 /* FIXME: this only function read values from dev */
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index 9f79c39349fb..a569be3e2f29 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/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;
                         }