libcamera: libcamera::ipa::V4L2Params< Traits > Class Template Reference

libcamera v0.7.2 Supporting cameras in Linux since 2019

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libcamera::ipa::V4L2Params< Traits > Class Template Reference

Helper class that represent an ISP configuration buffer. More...

Inheritance diagram for libcamera::ipa::V4L2Params< Traits >:
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Collaboration diagram for libcamera::ipa::V4L2Params< Traits >:
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## Public Member Functions
| V4L2Params (Span< uint8_t > data, unsigned int version)
| Construct an instance of V4L2Params.
template<typename Traits::id_type Id>
auto | block ()
| Retrieve the location of an ISP configuration block a return it.
Public Member Functions inherited from libcamera::ipa::V4L2ParamsBase
size_t | bytesused () const
| Retrieve the used size of the parameters buffer (in bytes).

## Additional Inherited Members
Protected Member Functions inherited from libcamera::ipa::V4L2ParamsBase
| V4L2ParamsBase (Span< uint8_t > data, unsigned int version)
| Construct an instance of V4L2ParamsBase.
Span< uint8_t > | block (uint16_t type, unsigned int blockType, size_t blockSize)
| Populate an ISP configuration block a returns a reference to its memory.
Protected Attributes inherited from libcamera::ipa::V4L2ParamsBase
Span< uint8_t > | data_
| The ISP parameters buffer memory.
size_t | used_
| The number of bytes used in the parameters buffer.
std::map< uint16_t, Span< uint8_t > > | blocks_
| Cache of ISP configuration blocks.

## Detailed Description

template<typename Traits>
class libcamera::ipa::V4L2Params< Traits >

Helper class that represent an ISP configuration buffer.

This class represents an ISP configuration buffer. It is constructed with a reference to the memory mapped buffer that will be queued to the ISP driver.

This class is templated with the type of the enumeration of ISP blocks that each IPA module is expected to support. IPA modules are expected to derive this class by providing a 'param_traits' type that helps the class associate a block type with the actual memory area that represents the ISP configuration block.

// Define the supported ISP blocks
enum class myISPBlocks {
Agc,
Awb,
...
};
// Maps the C++ enum type to the kernel enum type and concrete parameter type
template<myISPBlocks B>
struct block_type {
};
template<>
struct block_type<myISPBlocks::Agc> {
using type = struct my_isp_kernel_config_type_agc;
static constexpr kernel_enum_type blockType = MY_ISP_TYPE_AGC;
};
template<>
struct block_type<myISPBlocks::Awb> {
using type = struct my_isp_kernel_config_type_awb;
static constexpr kernel_enum_type blockType = MY_ISP_TYPE_AWB;
};
// Convenience type to associate a block id to the 'block_type' overload
struct params_traits {
using id_type = myISPBlocks;
template<id_type Id> using id_to_details = block_type<Id>;
};
...
// Derive the V4L2Params class by providing params_traits
class MyISPParams : public V4L2Params<params_traits>
{
public:
MyISPParams::MyISPParams(Span<uint8_t> data)
: V4L2Params(data, kVersion)
{
}
};
libcamera::ipa::V4L2Params::V4L2Params
V4L2Params(Span< uint8_t > data, unsigned int version)
Construct an instance of V4L2Params.
Definition v4l2_params.h:96

Users of this class can then easily access an ISP configuration block as a V4L2ParamsBlock instance.

MyISPParams params(data);
auto awb = params.block<myISPBlocks::AWB>();
awb->gain00 = ...;
awb->gain01 = ...;
awb->gain10 = ...;
awb->gain11 = ...;

## Constructor & Destructor Documentation

## ◆ V4L2Params()

template<typename Traits>

libcamera::ipa::V4L2Params< Traits >::V4L2Params | ( | Span< uint8_t > | data,
|  | unsigned int | version )
| inline

Construct an instance of V4L2Params.

Parameters

  [in] | data | Reference to the v4l2-buffer memory mapped area
  [in] | version | The ISP parameters version the implementation supports

## Member Function Documentation

## ◆ block()

template<typename Traits>
template<typename Traits::id_type Id>

auto libcamera::ipa::V4L2Params< Traits >::block | ( |  | ) |
| inline

Retrieve the location of an ISP configuration block a return it.

Returns
  A V4L2ParamsBlock instance that points to the ISP configuration block

The documentation for this class was generated from the following files:

- src/ipa/libipa/v4l2_params.h
- src/ipa/libipa/v4l2_params.cpp