Documentation/userspace-api/media/drivers/omap3isp-uapi.rst

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Linux kernel

Corpus path

Documentation/userspace-api/media/drivers/omap3isp-uapi.rst

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.rst

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8016 bytes

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209

Domain

Support Tooling And Documentation

Bucket

Documentation

Inferred role

Support Tooling And Documentation: documentation

Status

atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• No C-style include directives detected by the generator.

Detected Declarations

• No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

.. SPDX-License-Identifier: GPL-2.0

.. include:: <isonum.txt>

OMAP 3 Image Signal Processor (ISP) driver
==========================================

Copyright |copy| 2010 Nokia Corporation

Copyright |copy| 2009 Texas Instruments, Inc.

Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Sakari Ailus <sakari.ailus@iki.fi>, David Cohen <dacohen@gmail.com>


Events
------

The OMAP 3 ISP driver does support the V4L2 event interface on CCDC and
statistics (AEWB, AF and histogram) subdevs.

The CCDC subdev produces V4L2_EVENT_FRAME_SYNC type event on HS_VS
interrupt which is used to signal frame start. Earlier version of this
driver used V4L2_EVENT_OMAP3ISP_HS_VS for this purpose. The event is
triggered exactly when the reception of the first line of the frame starts
in the CCDC module. The event can be subscribed on the CCDC subdev.

(When using parallel interface one must pay account to correct configuration
of the VS signal polarity. This is automatically correct when using the serial
receivers.)

Each of the statistics subdevs is able to produce events. An event is
generated whenever a statistics buffer can be dequeued by a user space
application using the VIDIOC_OMAP3ISP_STAT_REQ IOCTL. The events available
are:

- V4L2_EVENT_OMAP3ISP_AEWB
- V4L2_EVENT_OMAP3ISP_AF
- V4L2_EVENT_OMAP3ISP_HIST

The type of the event data is struct omap3isp_stat_event_status for these
ioctls. If there is an error calculating the statistics, there will be an
event as usual, but no related statistics buffer. In this case
omap3isp_stat_event_status.buf_err is set to non-zero.


Private IOCTLs
--------------

The OMAP 3 ISP driver supports standard V4L2 IOCTLs and controls where
possible and practical. Much of the functions provided by the ISP, however,
does not fall under the standard IOCTLs --- gamma tables and configuration of
statistics collection are examples of such.

In general, there is a private ioctl for configuring each of the blocks
containing hardware-dependent functions.

The following private IOCTLs are supported:

- VIDIOC_OMAP3ISP_CCDC_CFG
- VIDIOC_OMAP3ISP_PRV_CFG
- VIDIOC_OMAP3ISP_AEWB_CFG
- VIDIOC_OMAP3ISP_HIST_CFG
- VIDIOC_OMAP3ISP_AF_CFG
- VIDIOC_OMAP3ISP_STAT_REQ
- VIDIOC_OMAP3ISP_STAT_EN

The parameter structures used by these ioctls are described in
include/linux/omap3isp.h. The detailed functions of the ISP itself related to
a given ISP block is described in the Technical Reference Manuals (TRMs) ---

Annotation

• Atlas domain: Support Tooling And Documentation / Documentation.
• Implementation status: atlas-only.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.