From 39d491761956b9c0e8c01ba5fc0a27558b90016e Mon Sep 17 00:00:00 2001 From: Jacopo Mondi Date: Wed, 30 Mar 2022 11:08:43 +0200 Subject: libcamera: v4l2_subdevice: Collect subdev capabilities Collect subdev capabilities at open() time. Model the V4L2SubdevCapabilties as V4L2Capability from the video device class. Signed-off-by: Jacopo Mondi Signed-off-by: Laurent Pinchart Tested-by: Jacopo Mondi Reviewed-by: Paul Elder Reviewed-by: Kieran Bingham --- include/libcamera/internal/v4l2_subdevice.h | 13 ++++++++ src/libcamera/v4l2_subdevice.cpp | 50 ++++++++++++++++++++++++++++- 2 files changed, 62 insertions(+), 1 deletion(-) diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h index 2db392d5..a1d3144c 100644 --- a/include/libcamera/internal/v4l2_subdevice.h +++ b/include/libcamera/internal/v4l2_subdevice.h @@ -29,6 +29,17 @@ namespace libcamera { class MediaDevice; +struct V4L2SubdeviceCapability final : v4l2_subdev_capability { + bool isReadOnly() const + { + return capabilities & V4L2_SUBDEV_CAP_RO_SUBDEV; + } + bool hasStreams() const + { + return capabilities & V4L2_SUBDEV_CAP_MPLEXED; + } +}; + struct V4L2SubdeviceFormat { uint32_t mbus_code; Size size; @@ -70,6 +81,7 @@ public: Whence whence = ActiveFormat); const std::string &model(); + const V4L2SubdeviceCapability &caps() const { return caps_; } static std::unique_ptr fromEntityName(const MediaDevice *media, const std::string &entity); @@ -87,6 +99,7 @@ private: const MediaEntity *entity_; std::string model_; + struct V4L2SubdeviceCapability caps_; }; } /* namespace libcamera */ diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp index 37960b76..a1672b23 100644 --- a/src/libcamera/v4l2_subdevice.cpp +++ b/src/libcamera/v4l2_subdevice.cpp @@ -133,6 +133,30 @@ const std::map formatInfoMap = { } /* namespace */ +/** + * \struct V4L2SubdeviceCapability + * \brief struct v4l2_subdev_capability object wrapper and helpers + * + * The V4L2SubdeviceCapability structure manages the information returned by the + * VIDIOC_SUBDEV_QUERYCAP ioctl. + */ + +/** + * \fn V4L2SubdeviceCapability::isReadOnly() + * \brief Retrieve if a subdevice is registered as read-only + * + * A V4L2 subdevice is registered as read-only if V4L2_SUBDEV_CAP_RO_SUBDEV + * is listed as part of its capabilities. + * + * \return True if the subdevice is registered as read-only, false otherwise + */ + +/** + * \fn V4L2SubdeviceCapability::hasStreams() + * \brief Retrieve if a subdevice supports the V4L2 streams API + * \return True if the subdevice supports the streams API, false otherwise + */ + /** * \struct V4L2SubdeviceFormat * \brief The V4L2 sub-device image format and sizes @@ -284,7 +308,25 @@ V4L2Subdevice::~V4L2Subdevice() */ int V4L2Subdevice::open() { - return V4L2Device::open(O_RDWR); + int ret = V4L2Device::open(O_RDWR); + if (ret) + return ret; + + /* + * Try to query the subdev capabilities. The VIDIOC_SUBDEV_QUERYCAP API + * was introduced in kernel v5.8, ENOTTY errors must be ignored to + * support older kernels. + */ + caps_ = {}; + ret = ioctl(VIDIOC_SUBDEV_QUERYCAP, &caps_); + if (ret < 0 && errno != ENOTTY) { + ret = -errno; + LOG(V4L2, Error) + << "Unable to query capabilities: " << strerror(-ret); + return ret; + } + + return 0; } /** @@ -527,6 +569,12 @@ const std::string &V4L2Subdevice::model() return model_; } +/** + * \fn V4L2Subdevice::caps() + * \brief Retrieve the subdevice V4L2 capabilities + * \return The subdevice V4L2 capabilities + */ + /** * \brief Create a new video subdevice instance from \a entity in media device * \a media -- cgit v1.2.1