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authorLinus Torvalds <torvalds@woody.osdl.org>2006-12-10 09:59:18 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-10 09:59:18 -0800
commitbb7320d1d96dc2e479180ae8e7a112caf0726ace (patch)
tree65a81fefd82d188f5496b70439db73ca911b3f76 /Documentation/video4linux/cafe_ccic
parent6aa8b732ca01c3d7a54e93f4d701b8aabbe60fb7 (diff)
parent1de1bf06330920802d3b7646a088965bdd918356 (diff)
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb
* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb: (132 commits) V4L/DVB 4949b: Fix container_of pointer retreival V4L/DVB (4949a): Fix INIT_WORK V4L/DVB (4949): Cxusb: codingstyle cleanups V4L/DVB (4948): Cxusb: Convert tuner functions to use dvb_pll_attach V4L/DVB (4947): Cx88: trivial cleanups V4L/DVB (4946): Cx88: Move cx88_dvb_bus_ctrl out of the card-specific area V4L/DVB (4945): Cx88: consolidate cx22702_config structs V4L/DVB (4944): Cx88: Convert DViCO FusionHDTV Hybrid to use dvb_pll_attach V4L/DVB (4943): Cx88: cleanup dvb_pll_attach for lgdt3302 tuners V4L/DVB (4953): Usbvision minor fixes V4L/DVB (4951): Add version.h, since it is required for VIDIOC_QUERYCAP V4L/DVB (4940): Or51211: Changed SNR and signal strength calculations V4L/DVB (4939): Or51132: Changed SNR and signal strength reporting V4L/DVB (4938): Cx88: Convert lgdt3302 tuning function to use dvb_pll_attach V4L/DVB (4941): Remove LINUX_VERSION_CODE and fix identations V4L/DVB (4942): Whitespace cleanups V4L/DVB (4937): Usbvision cleanup and code reorganization V4L/DVB (4936): Make MT4049FM5 tuner to set FM Gain to Normal V4L/DVB (4935): Added the capability of selecting fm gain by tuner V4L/DVB (4934): Usbvision radio requires GainNormal at e register ...
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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