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Maxime Ripard dfbfb7aa83 media: ov5640: Compute the clock rate at runtime
The clock rate, while hardcoded until now, is actually a function of the
resolution, framerate and bytes per pixel. Now that we have an algorithm to
adjust our clock rate, we can select it dynamically when we change the
mode.

This changes a bit the clock rate being used, with the following effect:

+------+------+------+------+-----+-----------------+----------------+-----------+
| Hact | Vact | Htot | Vtot | FPS | Hardcoded clock | Computed clock | Deviation |
+------+------+------+------+-----+-----------------+----------------+-----------+
|  640 |  480 | 1896 | 1080 |  15 |        56000000 |       61430400 | 8.84 %    |
|  640 |  480 | 1896 | 1080 |  30 |       112000000 |      122860800 | 8.84 %    |
| 1024 |  768 | 1896 | 1080 |  15 |        56000000 |       61430400 | 8.84 %    |
| 1024 |  768 | 1896 | 1080 |  30 |       112000000 |      122860800 | 8.84 %    |
|  320 |  240 | 1896 |  984 |  15 |        56000000 |       55969920 | 0.05 %    |
|  320 |  240 | 1896 |  984 |  30 |       112000000 |      111939840 | 0.05 %    |
|  176 |  144 | 1896 |  984 |  15 |        56000000 |       55969920 | 0.05 %    |
|  176 |  144 | 1896 |  984 |  30 |       112000000 |      111939840 | 0.05 %    |
|  720 |  480 | 1896 |  984 |  15 |        56000000 |       55969920 | 0.05 %    |
|  720 |  480 | 1896 |  984 |  30 |       112000000 |      111939840 | 0.05 %    |
|  720 |  576 | 1896 |  984 |  15 |        56000000 |       55969920 | 0.05 %    |
|  720 |  576 | 1896 |  984 |  30 |       112000000 |      111939840 | 0.05 %    |
| 1280 |  720 | 1892 |  740 |  15 |        42000000 |       42002400 | 0.01 %    |
| 1280 |  720 | 1892 |  740 |  30 |        84000000 |       84004800 | 0.01 %    |
| 1920 | 1080 | 2500 | 1120 |  15 |        84000000 |       84000000 | 0.00 %    |
| 1920 | 1080 | 2500 | 1120 |  30 |       168000000 |      168000000 | 0.00 %    |
| 2592 | 1944 | 2844 | 1944 |  15 |        84000000 |      165862080 | 49.36 %   |
+------+------+------+------+-----+-----------------+----------------+-----------+

Only the 640x480, 1024x768 and 2592x1944 modes are significantly affected
by the new formula.

In this case, 640x480 and 1024x768 are actually fixed by this change.
Indeed, the sensor was sending data at, for example, 27.33fps instead of
30fps. This is -9%, which is roughly what we're seeing in the array.
Testing these modes with the new clock setup actually fix that error, and
data are now sent at around 30fps.

2592x1944, on the other hand, is probably due to the fact that this mode
can only be used using MIPI-CSI2, in a two lane mode, and never really
tested with a DVP bus.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Adam Ford <aford173@gmail.com> #imx6dq
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2018-12-05 06:47:33 -05:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-11-03 18:25:17 -07:00
block for-linus-20181102 2018-11-02 11:25:48 -07:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto KEYS: asym_tpm: Add support for the sign operation [ver #2] 2018-10-26 09:30:47 +01:00
Documentation media: dt-bindings: media: mt9m111: add pclk-sample property 2018-12-05 06:40:34 -05:00
drivers media: ov5640: Compute the clock rate at runtime 2018-12-05 06:47:33 -05:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.