On 28/03/2022 16:13, Xavier Roumegue wrote: > Add user documentation for the DW100 driver. > > Signed-off-by: Xavier Roumegue <xavier.roumegue@xxxxxxxxxxx> > --- > .../userspace-api/media/drivers/dw100.rst | 23 +++++++++++++++++++ > .../userspace-api/media/drivers/index.rst | 1 + > 2 files changed, 24 insertions(+) > create mode 100644 Documentation/userspace-api/media/drivers/dw100.rst > > diff --git a/Documentation/userspace-api/media/drivers/dw100.rst b/Documentation/userspace-api/media/drivers/dw100.rst > new file mode 100644 > index 000000000000..4cd55c75628e > --- /dev/null > +++ b/Documentation/userspace-api/media/drivers/dw100.rst > @@ -0,0 +1,23 @@ > +.. 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 input image to correct distorsion > +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. Each x, y coordinate > +register uses 16 bits to record the coordinate address in UQ12.4 fixed point 'UQ12.4' is a mostly TI notation it seems: https://en.wikipedia.org/wiki/Q_(number_format) I would replace this with: ...in an unsigned 12.4 fixed point format And in the control documentation this can be documented more precisely (I'll comment on that patch). Regards, Hans > +format. > + > +The dewarping map can be set from application through a dedicated v4l2 control. > +If not set or invalid, the driver computes an identity map prior to start the > +processing engine. The map is evaluated as invalid if the array size does not > +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. > + > +.. _IMX8MP: https://www.nxp.com/webapp/Download?colCode=IMX8MPRM > diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst > index 12e3c512d718..8826777321b0 100644 > --- a/Documentation/userspace-api/media/drivers/index.rst > +++ b/Documentation/userspace-api/media/drivers/index.rst > @@ -33,6 +33,7 @@ For more details see the file COPYING in the source distribution of Linux. > > ccs > cx2341x-uapi > + dw100 > hantro > imx-uapi > max2175
