[media] davinci: vpfe: Add documentation and TODO
Add documentation on the Davinci VPFE driver. Document the subdevs, and private IOTCLs the driver implements. This patch also includes the TODO's to fit into drivers/media/ folder. Signed-off-by: Manjunath Hadli <manjunath.hadli@ti.com> Signed-off-by: Lad, Prabhakar <prabhakar.lad@ti.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Acked-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Manjunath Hadli
Mauro Carvalho Chehab
parent
44261e3805
commit
5a89fac7e9
|
|
@ -0,0 +1,37 @@
|
|||
TODO (general):
|
||||
==================================
|
||||
|
||||
- User space interface refinement
|
||||
- Controls should be used when possible rather than private ioctl
|
||||
- No enums should be used
|
||||
- Use of MC and V4L2 subdev APIs when applicable
|
||||
- Single interface header might suffice
|
||||
- Current interface forces to configure everything at once
|
||||
- Get rid of the dm365_ipipe_hw.[ch] layer
|
||||
- Active external sub-devices defined by link configuration; no strcmp
|
||||
needed
|
||||
- More generic platform data (i2c adapters)
|
||||
- The driver should have no knowledge of possible external subdevs; see
|
||||
struct vpfe_subdev_id
|
||||
- Some of the hardware control should be refactorede
|
||||
- Check proper serialisation (through mutexes and spinlocks)
|
||||
- Names that are visible in kernel global namespace should have a common
|
||||
prefix (or a few)
|
||||
- While replacing the older driver in media folder, provide a compatibility
|
||||
layer and compatibility tests that warrants (using the libv4l's LD_PRELOAD
|
||||
approach) there is no regression for the users using the older driver.
|
||||
|
||||
Building of uImage and Applications:
|
||||
==================================
|
||||
|
||||
As of now since the interface will undergo few changes all the include
|
||||
files are present in staging itself, to build for dm365 follow below steps,
|
||||
|
||||
- copy vpfe.h from drivers/staging/media/davinci_vpfe/ to
|
||||
include/media/davinci/ folder for building the uImage.
|
||||
- copy davinci_vpfe_user.h from drivers/staging/media/davinci_vpfe/ to
|
||||
include/uapi/linux/davinci_vpfe.h, and add a entry in Kbuild (required
|
||||
for building application).
|
||||
- copy dm365_ipipeif_user.h from drivers/staging/media/davinci_vpfe/ to
|
||||
include/uapi/linux/dm365_ipipeif.h and a entry in Kbuild (required
|
||||
for building application).
|
||||
|
|
@ -0,0 +1,154 @@
|
|||
Davinci Video processing Front End (VPFE) driver
|
||||
|
||||
Copyright (C) 2012 Texas Instruments Inc
|
||||
|
||||
Contacts: Manjunath Hadli <manjunath.hadli@ti.com>
|
||||
Prabhakar Lad <prabhakar.lad@ti.com>
|
||||
|
||||
|
||||
Introduction
|
||||
============
|
||||
|
||||
This file documents the Texas Instruments Davinci Video processing Front End
|
||||
(VPFE) driver located under drivers/media/platform/davinci. The original driver
|
||||
exists for Davinci VPFE, which is now being changed to Media Controller
|
||||
Framework.
|
||||
|
||||
Currently the driver has been successfully used on the following
|
||||
version of Davinci:
|
||||
|
||||
DM365/DM368
|
||||
|
||||
The driver implements V4L2, Media controller and v4l2_subdev interfaces. Sensor,
|
||||
lens and flash drivers using the v4l2_subdev interface in the kernel are
|
||||
supported.
|
||||
|
||||
|
||||
Split to subdevs
|
||||
================
|
||||
|
||||
The Davinci VPFE is split into V4L2 subdevs, each of the blocks inside the VPFE
|
||||
having one subdev to represent it. Each of the subdevs provide a V4L2 subdev
|
||||
interface to userspace.
|
||||
|
||||
DAVINCI ISIF
|
||||
DAVINCI IPIPEIF
|
||||
DAVINCI IPIPE
|
||||
DAVINCI CROP RESIZER
|
||||
DAVINCI RESIZER A
|
||||
DAVINCI RESIZER B
|
||||
|
||||
Each possible link in the VPFE is modeled by a link in the Media controller
|
||||
interface. For an example program see [1].
|
||||
|
||||
|
||||
ISIF, IPIPE, and RESIZER block IOCTLs
|
||||
======================================
|
||||
|
||||
The Davinci Video processing Front End (VPFE) driver supports standard V4L2
|
||||
IOCTLs and controls where possible and practical. Much of the functions provided
|
||||
by the VPFE, however, does not fall under the standard IOCTL's.
|
||||
|
||||
In general, there is a private ioctl for configuring each of the blocks
|
||||
containing hardware-dependent functions.
|
||||
|
||||
The following private IOCTLs are supported:
|
||||
|
||||
VIDIOC_VPFE_ISIF_[S/G]_RAW_PARAMS
|
||||
VIDIOC_VPFE_IPIPE_[S/G]_CONFIG
|
||||
VIDIOC_VPFE_RSZ_[S/G]_CONFIG
|
||||
|
||||
The parameter structures used by these ioctl's are described in
|
||||
include/uapi/linux/davinci_vpfe.h.
|
||||
|
||||
The VIDIOC_VPFE_ISIF_S_RAW_PARAMS, VIDIOC_VPFE_IPIPE_S_CONFIG and
|
||||
VIDIOC_VPFE_RSZ_S_CONFIG are used to configure, enable and disable functions in
|
||||
the isif, ipipe and resizer blocks respectively. These IOCTL's control several
|
||||
functions in the blocks they control. VIDIOC_VPFE_ISIF_S_RAW_PARAMS IOCTL
|
||||
accepts a pointer to struct vpfe_isif_raw_config as its argument. Similarly
|
||||
VIDIOC_VPFE_IPIPE_S_CONFIG accepts a pointer to struct vpfe_ipipe_config. And
|
||||
VIDIOC_VPFE_RSZ_S_CONFIG accepts a pointer to struct vpfe_rsz_config as its
|
||||
argument. Similarly VIDIOC_VPFE_ISIF_G_RAW_PARAMS, VIDIOC_VPFE_IPIPE_G_CONFIG
|
||||
and VIDIOC_VPFE_RSZ_G_CONFIG are used to get the current configuration set in
|
||||
the isif, ipipe and resizer blocks respectively.
|
||||
|
||||
The detailed functions of the VPFE itself related to a given VPFE block is
|
||||
described in the Technical Reference Manuals (TRMs) --- see the end of the
|
||||
document for those.
|
||||
|
||||
|
||||
IPIPEIF block IOCTLs
|
||||
======================================
|
||||
|
||||
The following private IOCTLs are supported:
|
||||
|
||||
VIDIOC_VPFE_IPIPEIF_[S/G]_CONFIG
|
||||
|
||||
The parameter structures used by these ioctl's are described in
|
||||
include/uapi/linux/dm365_ipipeif.h
|
||||
|
||||
The VIDIOC_VPFE_IPIPEIF_S_CONFIG is used to configure the ipipeif
|
||||
hardware block. The VIDIOC_VPFE_IPIPEIF_S_CONFIG and
|
||||
VIDIOC_VPFE_IPIPEIF_G_CONFIG accepts a pointer to struct ipipeif_params
|
||||
as its argument.
|
||||
|
||||
|
||||
VPFE Operating Modes
|
||||
==========================================
|
||||
|
||||
a: Continuous Modes
|
||||
------------------------
|
||||
|
||||
1: tvp514x/tvp7002/mt9p031---> DAVINCI ISIF---> SDRAM
|
||||
|
||||
2: tvp514x/tvp7002/mt9p031---> DAVINCI ISIF---> DAVINCI IPIPEIF--->|
|
||||
|
|
||||
<--------------------<----------------<---------------------<---|
|
||||
|
|
||||
V
|
||||
DAVINCI CROP RESIZER--->DAVINCI RESIZER [A/B]---> SDRAM
|
||||
|
||||
3: tvp514x/tvp7002/mt9p031---> DAVINCI ISIF---> DAVINCI IPIPEIF--->|
|
||||
|
|
||||
<--------------------<----------------<---------------------<---|
|
||||
|
|
||||
V
|
||||
DAVINCI IPIPE---> DAVINCI CROP RESIZER--->DAVINCI RESIZER [A/B]---> SDRAM
|
||||
|
||||
a: Single Shot Modes
|
||||
------------------------
|
||||
|
||||
1: SDRAM---> DAVINCI IPIPEIF---> DAVINCI IPIPE---> DAVINCI CROP RESIZER--->|
|
||||
|
|
||||
<----------------<----------------<------------------<---------------<--|
|
||||
|
|
||||
V
|
||||
DAVINCI RESIZER [A/B]---> SDRAM
|
||||
|
||||
2: SDRAM---> DAVINCI IPIPEIF---> DAVINCI CROP RESIZER--->|
|
||||
|
|
||||
<----------------<----------------<---------------<---|
|
||||
|
|
||||
V
|
||||
DAVINCI RESIZER [A/B]---> SDRAM
|
||||
|
||||
|
||||
Technical reference manuals (TRMs) and other documentation
|
||||
==========================================================
|
||||
|
||||
Davinci DM365 TRM:
|
||||
<URL:http://www.ti.com/lit/ds/sprs457e/sprs457e.pdf>
|
||||
Referenced MARCH 2009-REVISED JUNE 2011
|
||||
|
||||
Davinci DM368 TRM:
|
||||
<URL:http://www.ti.com/lit/ds/sprs668c/sprs668c.pdf>
|
||||
Referenced APRIL 2010-REVISED JUNE 2011
|
||||
|
||||
Davinci Video Processing Front End (VPFE) DM36x
|
||||
<URL:http://www.ti.com/lit/ug/sprufg8c/sprufg8c.pdf>
|
||||
|
||||
|
||||
References
|
||||
==========
|
||||
|
||||
[1] http://git.ideasonboard.org/?p=media-ctl.git;a=summary
|
||||
Loading…
Reference in New Issue