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Diffstat (limited to 'Documentation/userspace-api/media/drivers')
4 files changed, 86 insertions, 21 deletions
diff --git a/Documentation/userspace-api/media/drivers/dw100.rst b/Documentation/userspace-api/media/drivers/dw100.rst new file mode 100644 index 000000000000..fceea6ece622 --- /dev/null +++ b/Documentation/userspace-api/media/drivers/dw100.rst @@ -0,0 +1,84 @@ +.. SPDX-License-Identifier: GPL-2.0 + +DW100 dewarp driver +=================== + +The Vivante DW100 Dewarp Processor IP core found on i.MX8MP SoC applies a +programmable geometrical transformation on the input image to correct distortion +introduced by lenses. + +The transformation function is exposed by the hardware as a grid map with 16x16 +pixel macroblocks indexed using X, Y vertex coordinates. +:: + + Image width + <---------------------------------------> + + ^ .-------.-------.-------.-------.-------. + | | 16x16 | | | | | + I | | pixel | | | | | + m | | block | | | | | + a | .-------.-------.-------.-------.-------. + g | | | | | | | + e | | | | | | | + | | | | | | | + h | .-------.-------.-------.-------.-------. + e | | | | | | | + i | | | | | | | + g | | | | | | | + h | .-------.-------.-------.-------.-------. + t | | | | | | | + | | | | | | | + | | | | | | | + v '-------'-------'-------'-------'-------' + + Grid of Image Blocks for Dewarping Map + + +Each x, y coordinate register uses 16 bits to record the coordinate address in +an unsigned 12.4 fixed point format (UQ12.4). +:: + + .----------------------.--------..----------------------.--------. + | 31~20 | 19~16 || 15~4 | 3~0 | + | (integer) | (frac) || (integer) | (frac) | + '----------------------'--------''----------------------'--------' + <-------------------------------><-------------------------------> + Y coordinate X coordinate + + Remap Register Layout + +The dewarping map is set from applications using the +V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP control. The control contains +an array of u32 values storing (x, y) destination coordinates for each +vertex of the grid. The x coordinate is stored in the 16 LSBs and the y +coordinate in the 16 MSBs. + +The number of elements in the array must match the image size: + +.. code-block:: C + + elems = (DIV_ROUND_UP(width, 16) + 1) * (DIV_ROUND_UP(height, 16) + 1); + +If the control has not been set by the application, the driver uses an identity +map. + +More details on the DW100 hardware operations can be found in +*chapter 13.15 DeWarp* of IMX8MP_ reference manual. + +The Vivante DW100 m2m driver implements the following driver-specific control: + +``V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP (__u32 array)`` + Specifies to DW100 driver its dewarping map (aka LUT) blob as described in + *chapter 13.15.2.3 Dewarping Remap* of IMX8MP_ reference manual as an U32 + dynamic array. The image is divided into many small 16x16 blocks. If the + width/height of the image is not divisible by 16, the size of the + rightmost/bottommost block is the remainder. The dewarping map only saves + the vertex coordinates of the block. The dewarping grid map is comprised of + vertex coordinates for x and y. Each x, y coordinate register uses 16 bits + (UQ12.4) to record the coordinate address, with the Y coordinate in the + upper bits and X in the lower bits. The driver modifies the dimensions of + this control when the sink format is changed, to reflect the new input + resolution. + +.. _IMX8MP: https://www.nxp.com/webapp/Download?colCode=IMX8MPRM diff --git a/Documentation/userspace-api/media/drivers/hantro.rst b/Documentation/userspace-api/media/drivers/hantro.rst deleted file mode 100644 index cd9754b4e005..000000000000 --- a/Documentation/userspace-api/media/drivers/hantro.rst +++ /dev/null @@ -1,19 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -Hantro video decoder driver -=========================== - -The Hantro video decoder driver implements the following driver-specific controls: - -``V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (integer)`` - Specifies to Hantro HEVC video decoder driver the number of data (in bits) to - skip in the slice segment header. - If non-IDR, the bits to be skipped go from syntax element "pic_output_flag" - to before syntax element "slice_temporal_mvp_enabled_flag". - If IDR, the skipped bits are just "pic_output_flag" - (separate_colour_plane_flag is not supported). - -.. note:: - - This control is not yet part of the public kernel API and - it is expected to change. diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst index 12e3c512d718..32f82aed47d9 100644 --- a/Documentation/userspace-api/media/drivers/index.rst +++ b/Documentation/userspace-api/media/drivers/index.rst @@ -33,7 +33,7 @@ For more details see the file COPYING in the source distribution of Linux. ccs cx2341x-uapi - hantro + dw100 imx-uapi max2175 meye-uapi diff --git a/Documentation/userspace-api/media/drivers/uvcvideo.rst b/Documentation/userspace-api/media/drivers/uvcvideo.rst index e5fd8fad333c..a290f9fadae9 100644 --- a/Documentation/userspace-api/media/drivers/uvcvideo.rst +++ b/Documentation/userspace-api/media/drivers/uvcvideo.rst @@ -7,7 +7,7 @@ This file documents some driver-specific aspects of the UVC driver, such as driver-specific ioctls and implementation notes. Questions and remarks can be sent to the Linux UVC development mailing list at -linux-uvc-devel@lists.berlios.de. +linux-media@vger.kernel.org. Extension Unit (XU) support |