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2e7ee8bb24
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> |
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.. | ||
atmel-isc-base.c | ||
atmel-isc-regs.h | ||
atmel-isc.h | ||
atmel-isi.c | ||
atmel-isi.h | ||
atmel-sama5d2-isc.c | ||
Kconfig | ||
Makefile |