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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/video4linux/cafe_ccic
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
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+"cafe_ccic" is a driver for the Marvell 88ALP01 "cafe" CMOS camera
+controller. This is the controller found in first-generation OLPC systems,
+and this driver was written with support from the OLPC project.
+
+Current status: the core driver works. It can generate data in YUV422,
+RGB565, and RGB444 formats. (Anybody looking at the code will see RGB32 as
+well, but that is a debugging aid which will be removed shortly). VGA and
+QVGA modes work; CIF is there but the colors remain funky. Only the OV7670
+sensor is known to work with this controller at this time.
+
+To try it out: either of these commands will work:
+
+ mplayer tv:// -tv driver=v4l2:width=640:height=480 -nosound
+ mplayer tv:// -tv driver=v4l2:width=640:height=480:outfmt=bgr16 -nosound
+
+The "xawtv" utility also works; gqcam does not, for unknown reasons.
+
+There are a few load-time options, most of which can be changed after
+loading via sysfs as well:
+
+ - alloc_bufs_at_load: Normally, the driver will not allocate any DMA
+ buffers until the time comes to transfer data. If this option is set,
+ then worst-case-sized buffers will be allocated at module load time.
+ This option nails down the memory for the life of the module, but
+ perhaps decreases the chances of an allocation failure later on.
+
+ - dma_buf_size: The size of DMA buffers to allocate. Note that this
+ option is only consulted for load-time allocation; when buffers are
+ allocated at run time, they will be sized appropriately for the current
+ camera settings.
+
+ - n_dma_bufs: The controller can cycle through either two or three DMA
+ buffers. Normally, the driver tries to use three buffers; on faster
+ systems, however, it will work well with only two.
+
+ - min_buffers: The minimum number of streaming I/O buffers that the driver
+ will consent to work with. Default is one, but, on slower systems,
+ better behavior with mplayer can be achieved by setting to a higher
+ value (like six).
+
+ - max_buffers: The maximum number of streaming I/O buffers; default is
+ ten. That number was carefully picked out of a hat and should not be
+ assumed to actually mean much of anything.
+
+ - flip: If this boolean parameter is set, the sensor will be instructed to
+ invert the video image. Whether it makes sense is determined by how
+ your particular camera is mounted.
+
+Work is ongoing with this driver, stay tuned.
+
+jon
+
+Jonathan Corbet
+corbet@lwn.net