[media] em28xx: introduce #define for maximum supported scaling values (register...

The maximum supported scaling value for registers 0x30+0x31 (horizontal scaling)
and 0x32+0x33 (vertical scaling) is 0x3fff, which corresponds to 20% of the
input frame size.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/usb/em28xx/em28xx-reg.h b/drivers/media/usb/em28xx/em28xx-reg.h
index 885089e..0a3cb04 100644 (file)
--- a/drivers/media/usb/em28xx/em28xx-reg.h
+++ b/drivers/media/usb/em28xx/em28xx-reg.h
@@ -152,6 +152,8 @@
 #define EM28XX_R31_HSCALEHIGH  0x31
 #define EM28XX_R32_VSCALELOW   0x32
 #define EM28XX_R33_VSCALEHIGH  0x33
+#define   EM28XX_HVSCALE_MAX   0x3fff /* => 20% */
+
 #define EM28XX_R34_VBI_START_H 0x34
 #define EM28XX_R35_VBI_START_V 0x35
 #define EM28XX_R36_VBI_WIDTH   0x36

diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
index 6d26123..9451e1e 100644 (file)
--- a/drivers/media/usb/em28xx/em28xx-video.c
+++ b/drivers/media/usb/em28xx/em28xx-video.c
@@ -807,12 +807,12 @@ static void get_scale(struct em28xx *dev,
        unsigned int          maxh = norm_maxh(dev);
 
        *hscale = (((unsigned long)maxw) << 12) / width - 4096L;
-       if (*hscale >= 0x4000)
-               *hscale = 0x3fff;
+       if (*hscale > EM28XX_HVSCALE_MAX)
+               *hscale = EM28XX_HVSCALE_MAX;
 
        *vscale = (((unsigned long)maxh) << 12) / height - 4096L;
-       if (*vscale >= 0x4000)
-               *vscale = 0x3fff;
+       if (*vscale > EM28XX_HVSCALE_MAX)
+               *vscale = EM28XX_HVSCALE_MAX;
 }
 
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