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authorHans de Goede <hdegoede@redhat.com>2012-04-27 20:00:57 +0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-05-07 23:15:39 +0400
commit48bb7315f8205272c69fa49c732adb20b2f08614 (patch)
treea1baf253d1d5229795f3b6fbc7c4a15f6629c5a9 /drivers/media/video/gspca
parent895d464db68a98fe877f724cafb4c1f84b67492f (diff)
downloadlinux-48bb7315f8205272c69fa49c732adb20b2f08614.tar.xz
[media] gspca_pac7302: Document some more registers
Note like all info on the pac73xx chips, this info was found by trial and error, so it is not necessarily 100% correct. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/gspca')
-rw-r--r--drivers/media/video/gspca/pac7302.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/media/video/gspca/pac7302.c b/drivers/media/video/gspca/pac7302.c
index 1e88d3a574d9..a2a42f61d3c0 100644
--- a/drivers/media/video/gspca/pac7302.c
+++ b/drivers/media/video/gspca/pac7302.c
@@ -30,6 +30,14 @@
*
* Address Description
* 0x78 Global control, bit 6 controls the LED (inverted)
+ * 0x80 Compression balance, 2 interesting settings:
+ * 0x0f Default
+ * 0x50 Values >= this switch the camera to a lower compression,
+ * using the same table for both luminance and chrominance.
+ * This gives a sharper picture. Only usable when running
+ * at < 15 fps! Note currently the driver does not use this
+ * as the quality gain is small and the generated JPG-s are
+ * only understood by v4l-utils >= 0.8.9
*
* Register page 3:
*
@@ -43,8 +51,14 @@
* 1 -> ~30 fps, 2 -> ~20 fps
* 0x0e Exposure bits 0-7, 0-448, 0 = use full frame time
* 0x0f Exposure bit 8, 0-448, 448 = no exposure at all
- * 0x10 Master gain 0-31
+ * 0x10 Gain 0-31
+ * 0x12 Another gain 0-31, unlike 0x10 this one seems to start with an
+ * amplification value of 1 rather then 0 at its lowest setting
* 0x21 Bitfield: 0-1 unused, 2-3 vflip/hflip, 4-5 unknown, 6-7 unused
+ * 0x80 Another framerate control, best left at 1, moving it from 1 to
+ * 2 causes the framerate to become 3/4th of what it was, and
+ * also seems to cause pixel averaging, resulting in an effective
+ * resolution of 320x240 and thus a much blockier image
*
* The registers are accessed in the following functions:
*