The component offsets were computed in a negative way: they were
subtracted from the actual color component value.
So, a higher offset was reducing the component value.
This is not really desirable, as the offset is a 2's complements
number with 1 bit for sign and 12 value bits, so we would like to be able
to also add to the component, not only subtract.
The reported number in v4l2 is fine, a range from -4095 to +4095.
However when configuring a negative value for the offset, this would in
fact not function, because with the old code, the number was subtracted
from the max value. By setting something negative, it was overflowing in
fact. Reworked the component offsets by placing the real value as the
v4l2 ctrls.
Now, the values are the real number that is added or subtracted from
the component.
The negative values received from v4l2 are already in 2's complements, so
there is no need for conversion.
This actually simplifies a lot the computation procedure, eliminating the
need for the macros that convert from v4l2 values to ISC values and
viceversa.
Also the ZERO_VAL is eliminated, as 0 is now 0, as it's supposed to be.
Example after this change:
# v4l2-ctl --set-ctrl=red_component_offset=-150 -L
User Controls
brightness 0x00980900 (int) : min=-1024 max=1023 step=1 default=0 value=0 flags=slider
contrast 0x00980901 (int) : min=-2048 max=2047 step=1 default=16 value=20 flags=slider
white_balance_automatic 0x0098090c (bool) : default=1 value=0 flags=update
do_white_balance 0x0098090d (button) : flags=inactive, write-only, execute-on-write
gamma 0x00980910 (int) : min=0 max=3 step=1 default=3 value=3 flags=slider
red_component_gain 0x009819c0 (int) : min=0 max=8191 step=1 default=512 value=512 flags=slider
blue_component_gain 0x009819c1 (int) : min=0 max=8191 step=1 default=512 value=512 flags=slider
green_red_component_gain 0x009819c2 (int) : min=0 max=8191 step=1 default=512 value=512 flags=slider
green_blue_component_gain 0x009819c3 (int) : min=0 max=8191 step=1 default=512 value=512 flags=slider
red_component_offset 0x009819c4 (int) : min=-4095 max=4095 step=1 default=0 value=-150 flags=slider
blue_component_offset 0x009819c5 (int) : min=-4095 max=4095 step=1 default=0 value=0 flags=slider
green_red_component_offset 0x009819c6 (int) : min=-4095 max=4095 step=1 default=0 value=0 flags=slider
green_blue_component_offset 0x009819c7 (int) : min=-4095 max=4095 step=1 default=0 value=0 flags=slider
The auto white balance algorithm is unchanged, but the obtained value to
'subtract' is now converted to negative and saved as a v4l2 control and
displayed properly.
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This exposes the white balance configuration of the ISC as v4l2 controls
into userspace.
There are 8 controls available:
4 gain controls, sliders, for each of the BAYER components: R, B, GR, GB.
These gains are multipliers for each component, in format unsigned 0:4:9
with a default value of 512 (1.0 multiplier).
4 offset controls, sliders, for each of the BAYER components: R, B, GR, GB.
These offsets are added/substracted from each component, in format signed
1:12:0 with a default value of 0 (+/- 0)
To expose this to userspace, added 8 custom controls, in an auto cluster.
To summarize the functionality:
The auto cluster switch is the auto white balance control, and it works
like this:
AWB == 1: autowhitebalance is on, the do_white_balance button is inactive,
the gains/offsets are inactive, but volatile and readable.
Thus, the results of the whitebalance algorithm are available to userspace
to read at any time.
AWB == 0: autowhitebalance is off, cluster is in manual mode, user can
configure the gain/offsets directly. More than that, if the
do_white_balance button is pressed, the driver will perform
one-time-adjustment, (preferably with color checker card) and the userspace
can read again the new values.
With this feature, the userspace can save the coefficients and reinstall
them for example after reboot or reprobing the driver.
[hverkuil: fix checkpatch warning]
[hverkuil: minor spacing adjustments in the functionality description]
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Fixed issues that can lead to potential bugs.
Cleanup order in the driver
Taking into consideration std control creation can fail
mutex_destroy call
changing controller_formats with const specifier
some cosmetic cleanups
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This splits the Atmel ISC driver into a common base: atmel-isc-base.c
and the driver probe/dt part , atmel-sama5d2-isc.c
This is needed to keep a common ground for the sensor controller which will
be reused.
The atmel-isc will use the common symbols inside the atmel-isc-base
Future driver will also use the same symbols and redefine different aspects,
for a different version of the ISC.
This is done to avoid complete code duplication by creating a totally
different driver for the new variant of the ISC.
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil-cisco@xs4all.nl: folded 'atmel: atmel-sama5d2-isc: fixed checkpatch warnings' into this patch]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Eugen Hristev