On 28/03/2022 16:13, Xavier Roumegue wrote: > The DW100 driver gets the dewarping mapping as a binary blob from the > userspace application through a custom control. > The blob format is hardware specific so create a dedicated control for > this purpose. > > Signed-off-by: Xavier Roumegue <xavier.roumegue@xxxxxxxxxxx> > --- > Documentation/userspace-api/media/drivers/dw100.rst | 12 ++++++++++++ > include/uapi/linux/dw100.h | 11 +++++++++++ > 2 files changed, 23 insertions(+) > create mode 100644 include/uapi/linux/dw100.h > > diff --git a/Documentation/userspace-api/media/drivers/dw100.rst b/Documentation/userspace-api/media/drivers/dw100.rst > index 4cd55c75628e..f6d684cadf26 100644 > --- a/Documentation/userspace-api/media/drivers/dw100.rst > +++ b/Documentation/userspace-api/media/drivers/dw100.rst > @@ -20,4 +20,16 @@ match the expected size inherited from the destination image resolution. > More details on the DW100 hardware operations can be found in > *chapter 13.15 DeWarp* of IMX8MP_ reference manuel. > > +The Vivante DW100 m2m driver implements the following driver-specific control: > + > +``V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP (integer)`` (integer) -> (__u32 array) But should this be a __u32 array at all? Wouldn't a __u16 array make more sense? > + 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 of the image is not divisible by 16, the size of the rightmost block > + is the remainder. Isn't the same true for the height? 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 As mentioned before, UQ12.4 is not necessarily a standard notation. 'unsigned 12.4 fixed point' is better, but you also need to specify exactly where the bits are stored inside the __u16. I.e.: 'the integer part is stored in the 12 most significant bits, and the fractional part is stored in the 4 least significant bits of the __u16.' > + address, with the Y coordinate in the upper bits and X in the lower bits. And with a __u16 array this becomes: 'The array contains pairs of X, Y coordinates.' Or something along those lines. > + > .. _IMX8MP: https://www.nxp.com/webapp/Download?colCode=IMX8MPRM > diff --git a/include/uapi/linux/dw100.h b/include/uapi/linux/dw100.h > new file mode 100644 > index 000000000000..7fdcf2bf42e5 > --- /dev/null > +++ b/include/uapi/linux/dw100.h > @@ -0,0 +1,11 @@ > +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */ > +/* Copyright 2022 NXP */ > + > +#ifndef __UAPI_DW100_H__ > +#define __UAPI_DW100_H__ > + > +#include <linux/v4l2-controls.h> > + Add a comment referring to the Documentation/userspace-api/media/drivers/dw100.rst documentation so users of this control know where to find the associated documentation. > +#define V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP (V4L2_CID_USER_DW100_BASE + 1) > + > +#endif Regards, Hans
