[media] s5p-fimc: Add support for alpha component configuration
On Exynos SoCs the FIMC IP allows to configure globally the alpha component of all pixels for V4L2_PIX_FMT_RGB32, V4L2_PIX_FMT_RGB555 and V4L2_PIX_FMT_RGB444 image formats. This patch adds a v4l2 control in order to let the applications control the alpha component value. The alpha value range depends on the pixel format, for RGB32 it's 0..255 (8-bits), for RGB555 - 0..1 (1-bit) and for RGB444 - 0..15 (4-bits). The v4l2 control range is always 0..255 and the alpha component data width is determined by currently set format on the V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE buffer queue. The applications need to match the alpha channel value range and the pixel format since the driver will clamp the alpha component. Depending on fourcc the valid alpha bits are: - V4L2_PIX_FMT_RGB555 [0] - V4L2_PIX_FMT_RGB444 [3:0] - V4L2_PIX_FMT_RGB32 [7:0] When switching to a pixel format with smaller alpha component width the currently set alpha value will be clamped to maximum value valid for current format. When switching to a format with wider alpha the alpha value remains unchanged. The variant description data structure is extended with a new entry so an additional control is created only where really supported by the hardware. V4L2_PIX_FMT_RGB555 and V4L2_PIX_FMT_RGB444 formats are only valid for V4L2_BUF_TYPE_VIDEO_CAPTURE buffer queue. Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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