20ea6adbf1
Build system: x86_64 Build-tested: bcm2708, bcm2709, bcm2710, bcm2711 Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B Signed-off-by: Marty Jones <mj8263788@gmail.com> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
49 lines
2.1 KiB
Diff
49 lines
2.1 KiB
Diff
From dd91fe58de578570d49fe644eb05398a27510478 Mon Sep 17 00:00:00 2001
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From: David Plowman <david.plowman@raspberrypi.com>
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Date: Mon, 16 Aug 2021 13:39:09 +0200
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Subject: [PATCH] media: v4l2-ctrls: Document V4L2_CID_NOTIFY_GAINS
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control
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commit 311a839a1ad255ebcb7291fb4e0d2ec2f32312a7 upstream.
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Add documentation for the V4L2_CID_NOTIFY_GAINS control.
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This control is required by sensors that need to know what colour
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gains will be applied to pixels by downstream processing (such as by
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an ISP), though the sensor does not apply these gains itself.
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Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
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Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
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Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
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---
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.../media/v4l/ext-ctrls-image-source.rst | 20 +++++++++++++++++++
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1 file changed, 20 insertions(+)
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--- a/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
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+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-image-source.rst
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@@ -72,3 +72,23 @@ Image Source Control IDs
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* - __u32
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- ``height``
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- Height of the area.
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+
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+``V4L2_CID_NOTIFY_GAINS (integer array)``
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+ The sensor is notified what gains will be applied to the different
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+ colour channels by subsequent processing (such as by an ISP). The
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+ sensor is merely informed of these values in case it performs
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+ processing that requires them, but it does not apply them itself to
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+ the output pixels.
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+
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+ Currently it is defined only for Bayer sensors, and is an array
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+ control taking 4 gain values, being the gains for each of the
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+ Bayer channels. The gains are always in the order B, Gb, Gr and R,
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+ irrespective of the exact Bayer order of the sensor itself.
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+
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+ The use of an array allows this control to be extended to sensors
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+ with, for example, non-Bayer CFAs (colour filter arrays).
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+
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+ The units for the gain values are linear, with the default value
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+ representing a gain of exactly 1.0. For example, if this default value
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+ is reported as being (say) 128, then a value of 192 would represent
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+ a gain of exactly 1.5.
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