[Letux-kernel] [Gta04-owner] On camera driver

H. Nikolaus Schaller hns at goldelico.com
Tue Aug 9 23:29:16 CEST 2016


> Am 09.08.2016 um 23:05 schrieb Andrey Utkin <andrey_utkin at fastmail.com>:
> 
> On Tue, Aug 09, 2016 at 10:16:09PM +0200, H. Nikolaus Schaller wrote:
>> 
>>> Am 09.08.2016 um 20:12 schrieb Andrey Utkin <andrey_utkin at fastmail.com>:
>>> 
>>> On Tue, Aug 09, 2016 at 08:02:22PM +0200, H. Nikolaus Schaller wrote:
>>>> I think the ISP driver should create them...
>>> 
>>> I'll look at it later when I have time.
>>> ISP is synonymous to the camera, right? And the only driver involved is
>>> ov9650?
>> 
>> ISP is the Image Signal Processor within the OMAP3/DM3730 SoC. It
>> can transcode between pixel formats.
>> 
>> The camera is an external module connected to some OMAP3 interface.
>> 
>> Both have separate drivers for power control and parameter settings.
> 
> Thanks for explanation. What is the driver for ISP?

drivers/media/platform/omap3isp

I did find some more info:

root at letux:~# find /dev -name '*isp*'
/dev/v4l/by-path/platform-480bc000.isp-video-index6
/dev/v4l/by-path/platform-480bc000.isp-video-index5
/dev/v4l/by-path/platform-480bc000.isp-video-index4
/dev/v4l/by-path/platform-480bc000.isp-video-index3
/dev/v4l/by-path/platform-480bc000.isp-video-index2
/dev/v4l/by-path/platform-480bc000.isp-video-index1
/dev/v4l/by-path/platform-480bc000.isp-video-index0

and

root at letux:~# ls -l /dev/v4l/by-path/platform-480bc000.isp-video-index0
lrwxrwxrwx 1 root root 12 Aug  9 21:10 /dev/v4l/by-path/platform-480bc000.isp-video-index0 -> ../../video0
root at letux:~#

So the isp does not longer create /dev/media0 but a link to /dev/video0

This means I should try media-ctl -d /dev/video0 -p...

Next interesting thing is

eoot at letux:/sys/bus/platform/devices/480bc000.isp# ls -l  video4linux/video*/name
-r--r--r-- 1 root root 4096 Aug  9 21:18 video4linux/video0/name
-r--r--r-- 1 root root 4096 Aug  9 21:19 video4linux/video1/name
-r--r--r-- 1 root root 4096 Aug  9 21:19 video4linux/video2/name
-r--r--r-- 1 root root 4096 Aug  9 21:19 video4linux/video3/name
-r--r--r-- 1 root root 4096 Aug  9 21:19 video4linux/video4/name
-r--r--r-- 1 root root 4096 Aug  9 21:19 video4linux/video5/name
-r--r--r-- 1 root root 4096 Aug  9 21:19 video4linux/video6/name
root at letux:/sys/bus/platform/devices/480bc000.isp# cat video4linux/video*/name
OMAP3 ISP CCP2 input
OMAP3 ISP CSI2a output
OMAP3 ISP CCDC output
OMAP3 ISP preview input
OMAP3 ISP preview output
OMAP3 ISP resizer input
OMAP3 ISP resizer output
root at letux:/sys/bus/platform/devices/480bc000.isp# 

This confirms that the ISP stages are now available as /dev/video*

And video0 is the camera interface (CCP2 input).

Hm...

root at letux:~# media-ctl  '"ov9655 2-0030":0 [UYVY2X8 1280x1024]' -d /dev/media0
Failed to enumerate /dev/media0 (-2)
root at letux:~# media-ctl  '"ov9655 2-0030":0 [UYVY2X8 1280x1024]' -d /dev/video0
Failed to enumerate /dev/video0 (-25)
root at letux:~# 

-2 is ENOENT. Well, the file does not exist.
-25 is ENOTTY. That is strange. I didn't expect a tty...

root at letux:~# media-ctl -v -d /dev/video0 -p
Opening media device /dev/video0
media_device_enumerate: Unable to retrieve media device information for device /dev/video0 (Inappropriate ioctl for device)
Failed to enumerate /dev/video0 (-25)
root at letux:~# 

Hm. Something is wrong. Mismatch between media-ctl version and kernel?

One thing that is suspicious is that media-ctl tries /dev/media0 by default.

So the v4l2-utils package of Debian Jessie might be simply incompatible to the kernel!

Do you know some release notes about such compatibility?

BR,
Nikolaus
 


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