[libcamera-devel] [PATCH v5 2/4] libcamera: Introduce V4L2Device base class

Laurent Pinchart laurent.pinchart at ideasonboard.com
Wed Jun 19 14:20:29 CEST 2019


Hi Jacopo,

Thank you for the patch.

On Wed, Jun 19, 2019 at 01:05:46PM +0200, Jacopo Mondi wrote:
> The V4L2 devices and subdevices share a few common operations,like
> opening and closing a device node, and perform IOCTLs on the device.
> 
> With the forthcoming introduction of support for V4L2 controls, the
> quantity of shared code will increase, as the control support
> implementation is identical for the two derived classes.
> 
> To maximize code re-use and avoid duplications, provide a V4L2Device
> base class which groups the common operations and members.
> 
> The newly introduced base class provides methods to open/close a device
> node, access the file descriptor, and perform IOCTLs on the device.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
>  src/libcamera/include/v4l2_device.h      |  43 +++++++
>  src/libcamera/include/v4l2_subdevice.h   |   9 +-
>  src/libcamera/include/v4l2_videodevice.h |  10 +-
>  src/libcamera/meson.build                |   2 +
>  src/libcamera/v4l2_device.cpp            | 144 +++++++++++++++++++++++
>  src/libcamera/v4l2_subdevice.cpp         |  84 +++----------
>  src/libcamera/v4l2_videodevice.cpp       | 103 +++++-----------
>  7 files changed, 239 insertions(+), 156 deletions(-)
>  create mode 100644 src/libcamera/include/v4l2_device.h
>  create mode 100644 src/libcamera/v4l2_device.cpp
> 
> diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
> new file mode 100644
> index 000000000000..2c26f3eae2b4
> --- /dev/null
> +++ b/src/libcamera/include/v4l2_device.h
> @@ -0,0 +1,43 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2019, Google Inc.
> + *
> + * v4l2_device.h - Common base for V4L2 video devices and subdevices
> + */
> +#ifndef __LIBCAMERA_V4L2_DEVICE_H__
> +#define __LIBCAMERA_V4L2_DEVICE_H__
> +
> +#include <string>
> +
> +#include "log.h"
> +
> +namespace libcamera {
> +
> +class V4L2Device : protected Loggable
> +{
> +public:
> +	void close();
> +	bool isOpen() const { return fd_ != -1; }
> +	const std::string &deviceNode() const { return deviceNode_; }
> +
> +protected:
> +	V4L2Device(const std::string &deviceNode, const std::string &logTag);
> +	~V4L2Device() {}
> +
> +	int fd() { return fd_; }
> +
> +	int open(unsigned int flags);
> +
> +	int ioctl(unsigned long request, void *argp);
> +
> +	std::string logPrefix() const { return "'" + logTag_ + "'"; }

Let's try not to inline methods that are more complex than just
returning a member of the class.

I didn't notice in my previous review that V4L2Subdevice was using the
entity name as a prefix. I'm afraid my comment about moving logPrefix()
to V4L2Device was a bad one :-/ However, V4L2Device should still inherit
from Loggable. It will thus have a pure virtual logPrefix() inherited
from Loggable, requiring the derived classes to implement that method,
but allowing LOG() statements in V4L2Device to use the log prefix.

Here's the diff I came up with, it can be squashed with this patch if
you agree on the comments.

diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
index 2c26f3eae2b4..8c83adab4d43 100644
--- a/src/libcamera/include/v4l2_device.h
+++ b/src/libcamera/include/v4l2_device.h
@@ -21,7 +21,7 @@ public:
 	const std::string &deviceNode() const { return deviceNode_; }

 protected:
-	V4L2Device(const std::string &deviceNode, const std::string &logTag);
+	V4L2Device(const std::string &deviceNode);
 	~V4L2Device() {}

 	int fd() { return fd_; }
@@ -30,11 +30,8 @@ protected:

 	int ioctl(unsigned long request, void *argp);

-	std::string logPrefix() const { return "'" + logTag_ + "'"; }
-
 private:
 	std::string deviceNode_;
-	std::string logTag_;
 	int fd_;
 };

diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
index b1da4a87c553..9c077674f997 100644
--- a/src/libcamera/include/v4l2_subdevice.h
+++ b/src/libcamera/include/v4l2_subdevice.h
@@ -52,6 +52,9 @@ public:
 	static V4L2Subdevice *fromEntityName(const MediaDevice *media,
 					     const std::string &entity);

+protected:
+	std::string logPrefix() const;
+
 private:
 	std::vector<unsigned int> enumPadCodes(unsigned int pad);
 	std::vector<SizeRange> enumPadSizes(unsigned int pad,
diff --git a/src/libcamera/include/v4l2_videodevice.h b/src/libcamera/include/v4l2_videodevice.h
index e73dec13f847..734b34f1dc53 100644
--- a/src/libcamera/include/v4l2_videodevice.h
+++ b/src/libcamera/include/v4l2_videodevice.h
@@ -147,6 +147,9 @@ public:
 	static V4L2VideoDevice *fromEntityName(const MediaDevice *media,
 					       const std::string &entity);

+protected:
+	std::string logPrefix() const;
+
 private:
 	int getFormatMeta(V4L2DeviceFormat *format);
 	int setFormatMeta(V4L2DeviceFormat *format);
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index eeed0a70fb0e..1f113780ba45 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -68,17 +68,15 @@ void V4L2Device::close()
 /**
  * \brief Construct a V4L2Device
  * \param[in] deviceNode The device node filesystem path
- * \param[in] logTag The tag to prefix log messages with. Helpful to identify
- * the device in the log output
  *
  * The V4L2Device constructor is protected and can only be accessed by the
  * V4L2VideoDevice and V4L2Subdevice derived classes.
  *
  * Initialize the file descriptor to -1 and store the \a deviceNode to be used
  * at open() time, and the \a logTag to prefix log messages with.
  */
-V4L2Device::V4L2Device(const std::string &deviceNode, const std::string &logTag)
-	: deviceNode_(deviceNode), logTag_(logTag), fd_(-1)
+V4L2Device::V4L2Device(const std::string &deviceNode)
+	: deviceNode_(deviceNode), fd_(-1)
 {
 }

@@ -99,6 +94,7 @@ V4L2Device::V4L2Device(const std::string &deviceNode, const std::string &logTag)
  */
 int V4L2Device::open(unsigned int flags)
 {
+	LOG(V4L2, Info) << "Opening device";
 	if (isOpen()) {
 		LOG(V4L2, Error) << "Device already open";
 		return -EBUSY;
@@ -135,10 +131,4 @@ int V4L2Device::ioctl(unsigned long request, void *argp)
 	return 0;
 }

-/**
- * \fn V4L2Device::logPrefix()
- * \brief Retrieve the tag to prefix log messages with
- * \return The tag to prefix log messages with
- */
-
 } /* namespace libcamera */
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index d0e1d717b26c..a188298de34c 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -102,7 +102,7 @@ const std::string V4L2SubdeviceFormat::toString() const
  * path
  */
 V4L2Subdevice::V4L2Subdevice(const MediaEntity *entity)
-	: V4L2Device(entity->deviceNode(), entity->name()), entity_(entity)
+	: V4L2Device(entity->deviceNode()), entity_(entity)
 {
 }

@@ -265,6 +265,11 @@ V4L2Subdevice *V4L2Subdevice::fromEntityName(const MediaDevice *media,
 	return new V4L2Subdevice(mediaEntity);
 }

+std::string V4L2Subdevice::logPrefix() const
+{
+	return "'" + entity_->name() + "'";
+}
+
 std::vector<unsigned int> V4L2Subdevice::enumPadCodes(unsigned int pad)
 {
 	std::vector<unsigned int> codes;
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index 403e0b2e0653..2de3751f467e 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -270,7 +270,7 @@ const std::string V4L2DeviceFormat::toString() const
  * \param[in] deviceNode The file-system path to the video device node
  */
 V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
-	: V4L2Device(deviceNode, deviceNode), bufferPool_(nullptr),
+	: V4L2Device(deviceNode), bufferPool_(nullptr),
 	  queuedBuffersCount_(0), fdEvent_(nullptr)
 {
 	/*
@@ -389,6 +389,11 @@ void V4L2VideoDevice::close()
  * \return The string containing the device location
  */

+std::string V4L2VideoDevice::logPrefix() const
+{
+	return deviceNode() + (V4L2_TYPE_IS_OUTPUT(bufferType_) ? "[out]" : "[cap]");
+}
+
 /**
  * \brief Retrieve the image format set on the V4L2 device
  * \param[out] format The image format applied on the device

> +
> +private:
> +	std::string deviceNode_;
> +	std::string logTag_;
> +	int fd_;
> +};
> +
> +} /* namespace libcamera */
> +
> +#endif /* __LIBCAMERA_V4L2_DEVICE_H__ */
> diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
> index 9afd28b6db02..b1da4a87c553 100644
> --- a/src/libcamera/include/v4l2_subdevice.h
> +++ b/src/libcamera/include/v4l2_subdevice.h
> @@ -16,6 +16,7 @@
>  #include "formats.h"
>  #include "log.h"
>  #include "media_object.h"
> +#include "v4l2_device.h"
>  
>  namespace libcamera {
>  
> @@ -28,7 +29,7 @@ struct V4L2SubdeviceFormat {
>  	const std::string toString() const;
>  };
>  
> -class V4L2Subdevice : protected Loggable
> +class V4L2Subdevice : public V4L2Device
>  {
>  public:
>  	explicit V4L2Subdevice(const MediaEntity *entity);
> @@ -37,8 +38,6 @@ public:
>  	~V4L2Subdevice();
>  
>  	int open();
> -	bool isOpen() const;
> -	void close();
>  
>  	const MediaEntity *entity() const { return entity_; }
>  
> @@ -53,9 +52,6 @@ public:
>  	static V4L2Subdevice *fromEntityName(const MediaDevice *media,
>  					     const std::string &entity);
>  
> -protected:
> -	std::string logPrefix() const;
> -
>  private:
>  	std::vector<unsigned int> enumPadCodes(unsigned int pad);
>  	std::vector<SizeRange> enumPadSizes(unsigned int pad,
> @@ -65,7 +61,6 @@ private:
>  			 Rectangle *rect);
>  
>  	const MediaEntity *entity_;
> -	int fd_;
>  };
>  
>  } /* namespace libcamera */
> diff --git a/src/libcamera/include/v4l2_videodevice.h b/src/libcamera/include/v4l2_videodevice.h
> index 895658805b47..e73dec13f847 100644
> --- a/src/libcamera/include/v4l2_videodevice.h
> +++ b/src/libcamera/include/v4l2_videodevice.h
> @@ -18,6 +18,7 @@
>  
>  #include "formats.h"
>  #include "log.h"
> +#include "v4l2_device.h"
>  
>  namespace libcamera {
>  
> @@ -112,7 +113,7 @@ public:
>  	const std::string toString() const;
>  };
>  
> -class V4L2VideoDevice : protected Loggable
> +class V4L2VideoDevice : public V4L2Device
>  {
>  public:
>  	explicit V4L2VideoDevice(const std::string &deviceNode);
> @@ -123,13 +124,11 @@ public:
>  	V4L2VideoDevice &operator=(const V4L2VideoDevice &) = delete;
>  
>  	int open();
> -	bool isOpen() const;
>  	void close();
>  
>  	const char *driverName() const { return caps_.driver(); }
>  	const char *deviceName() const { return caps_.card(); }
>  	const char *busName() const { return caps_.bus_info(); }
> -	const std::string &deviceNode() const { return deviceNode_; }
>  
>  	int getFormat(V4L2DeviceFormat *format);
>  	int setFormat(V4L2DeviceFormat *format);
> @@ -148,9 +147,6 @@ public:
>  	static V4L2VideoDevice *fromEntityName(const MediaDevice *media,
>  					       const std::string &entity);
>  
> -protected:
> -	std::string logPrefix() const;
> -
>  private:
>  	int getFormatMeta(V4L2DeviceFormat *format);
>  	int setFormatMeta(V4L2DeviceFormat *format);
> @@ -171,8 +167,6 @@ private:
>  	Buffer *dequeueBuffer();
>  	void bufferAvailable(EventNotifier *notifier);
>  
> -	std::string deviceNode_;
> -	int fd_;
>  	V4L2Capability caps_;
>  
>  	enum v4l2_buf_type bufferType_;
> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> index 15ab53b1abbe..f26ad5b2dc57 100644
> --- a/src/libcamera/meson.build
> +++ b/src/libcamera/meson.build
> @@ -23,6 +23,7 @@ libcamera_sources = files([
>      'stream.cpp',
>      'timer.cpp',
>      'utils.cpp',
> +    'v4l2_device.cpp',
>      'v4l2_subdevice.cpp',
>      'v4l2_videodevice.cpp',
>  ])
> @@ -41,6 +42,7 @@ libcamera_headers = files([
>      'include/media_object.h',
>      'include/pipeline_handler.h',
>      'include/utils.h',
> +    'include/v4l2_device.h',
>      'include/v4l2_subdevice.h',
>      'include/v4l2_videodevice.h',
>  ])
> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> new file mode 100644
> index 000000000000..eeed0a70fb0e
> --- /dev/null
> +++ b/src/libcamera/v4l2_device.cpp
> @@ -0,0 +1,144 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2019, Google Inc.
> + *
> + * v4l2_device.cpp - Common base for V4L2 video devices and subdevices
> + */
> +
> +#include "v4l2_device.h"
> +
> +#include <fcntl.h>
> +#include <string.h>
> +#include <sys/ioctl.h>
> +#include <unistd.h>
> +
> +#include "log.h"
> +
> +/**
> + * \file v4l2_device.h
> + * \brief Common base for V4L2 devices and subdevices
> + */
> +
> +namespace libcamera {
> +
> +LOG_DEFINE_CATEGORY(V4L2)
> +
> +/**
> + * \class V4L2Device
> + * \brief Base class for V4L2VideoDevice and V4L2Subdevice
> + *
> + * The V4L2Device class groups together the methods and fields common to
> + * both the V4L2VideoDevice and V4L2Subdevice classes, and provides a base
> + * class whith methods to open and close the device node associated with the
> + * device and to perform IOCTL system calls on it.
> + *
> + * The V4L2Device class cannot be instantiated directly, as its constructor
> + * is protected. Users should instead create instances of one the derived
> + * classes to model either a V4L2 video device or a V4L2 subdevice.
> + */
> +
> +/**
> + * \brief Close the device node
> + *
> + * Reset the file descriptor to -1
> + */
> +void V4L2Device::close()
> +{
> +	if (!isOpen())
> +		return;
> +
> +	if (::close(fd_) < 0)
> +		LOG(V4L2, Error) << "Failed to close V4L2 device: "
> +				 << strerror(errno);
> +	fd_ = -1;
> +}
> +
> +/**
> + * \fn V4L2Device::isOpen()
> + * \brief Check if the V4L2 device node is open
> + * \return True if the V4L2 device node is open, false otherwise
> + */
> +
> +/**
> + * \fn V4L2Device::deviceNode()
> + * \brief Retrieve the device node path
> + * \return The device node path
> + */
> +
> +/**
> + * \brief Construct a V4L2Device
> + * \param[in] deviceNode The device node filesystem path
> + * \param[in] logTag The tag to prefix log messages with. Helpful to identify
> + * the device in the log output
> + *
> + * The V4L2Device constructor is protected and can only be accessed by the
> + * V4L2VideoDevice and V4L2Subdevice derived classes.

I would drop this sentence.

> + *
> + * Initialize the file descriptor to -1 and store the \a deviceNode to be used
> + * at open() time, and the \a logTag to prefix log messages with.
> + */
> +V4L2Device::V4L2Device(const std::string &deviceNode, const std::string &logTag)
> +	: deviceNode_(deviceNode), logTag_(logTag), fd_(-1)
> +{
> +}
> +
> +/**
> + * \fn V4L2Device::fd()
> + * \brief Retrieve the V4L2 device file descriptor
> + * \return The V4L2 device file descriptor, -1 if the device node is not open
> + */
> +
> +/**
> + * \brief Open a V4L2 device node
> + * \param[in] flags Access mode flags
> + *
> + * Open the device node path with the provided access mode \a flags and
> + * initialize the file descriptor, which was initially set to -1.
> + *
> + * \return 0 on success or a negative error code otherwise
> + */
> +int V4L2Device::open(unsigned int flags)
> +{
> +	if (isOpen()) {
> +		LOG(V4L2, Error) << "Device already open";
> +		return -EBUSY;
> +	}
> +
> +	int ret = ::open(deviceNode_.c_str(), flags);
> +	if (ret < 0) {
> +		ret = -errno;
> +		LOG(V4L2, Error) << "Failed to open V4L2 device: "
> +				 << strerror(-ret);
> +		return ret;
> +	}
> +
> +	fd_ = ret;
> +
> +	return 0;
> +}
> +
> +/**
> + * \brief Perform an IOCTL system call on the device node
> + * \param[in] request The IOCTL request code
> + * \param[in] argp A pointer to the IOCTL argument
> + * \return 0 on success or a negative error code otherwise
> + */
> +int V4L2Device::ioctl(unsigned long request, void *argp)
> +{
> +	/*
> +	 * Printing out an error message is usually better performed
> +	 * in the caller, which can provide more context.
> +	 */
> +	if (::ioctl(fd_, request, argp) < 0)
> +		return -errno;
> +
> +	return 0;
> +}
> +
> +/**
> + * \fn V4L2Device::logPrefix()
> + * \brief Retrieve the tag to prefix log messages with
> + * \return The tag to prefix log messages with
> + */
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
> index 48f1fcb30ed4..d0e1d717b26c 100644
> --- a/src/libcamera/v4l2_subdevice.cpp
> +++ b/src/libcamera/v4l2_subdevice.cpp
> @@ -29,7 +29,7 @@
>  
>  namespace libcamera {
>  
> -LOG_DEFINE_CATEGORY(V4L2Subdev)
> +LOG_DECLARE_CATEGORY(V4L2)
>  
>  /**
>   * \struct V4L2SubdeviceFormat
> @@ -102,7 +102,7 @@ const std::string V4L2SubdeviceFormat::toString() const
>   * path
>   */
>  V4L2Subdevice::V4L2Subdevice(const MediaEntity *entity)
> -	: entity_(entity), fd_(-1)
> +	: V4L2Device(entity->deviceNode(), entity->name()), entity_(entity)
>  {
>  }
>  
> @@ -117,45 +117,7 @@ V4L2Subdevice::~V4L2Subdevice()
>   */
>  int V4L2Subdevice::open()
>  {
> -	int ret;
> -
> -	if (isOpen()) {
> -		LOG(V4L2Subdev, Error) << "Device already open";
> -		return -EBUSY;
> -	}
> -
> -	ret = ::open(entity_->deviceNode().c_str(), O_RDWR);
> -	if (ret < 0) {
> -		ret = -errno;
> -		LOG(V4L2Subdev, Error)
> -			<< "Failed to open V4L2 subdevice '"
> -			<< entity_->deviceNode() << "': " << strerror(-ret);
> -		return ret;
> -	}
> -	fd_ = ret;
> -
> -	return 0;
> -}
> -
> -/**
> - * \brief Check if the subdevice is open
> - * \return True if the subdevice is open, false otherwise
> - */
> -bool V4L2Subdevice::isOpen() const
> -{
> -	return fd_ != -1;
> -}
> -
> -/**
> - * \brief Close the subdevice, releasing any resources acquired by open()
> - */
> -void V4L2Subdevice::close()
> -{
> -	if (!isOpen())
> -		return;
> -
> -	::close(fd_);
> -	fd_ = -1;
> +	return V4L2Device::open(O_RDWR);
>  }
>  
>  /**
> @@ -200,7 +162,7 @@ ImageFormats V4L2Subdevice::formats(unsigned int pad)
>  	ImageFormats formats;
>  
>  	if (pad >= entity_->pads().size()) {
> -		LOG(V4L2Subdev, Error) << "Invalid pad: " << pad;
> +		LOG(V4L2, Error) << "Invalid pad: " << pad;
>  		return {};
>  	}
>  
> @@ -210,7 +172,7 @@ ImageFormats V4L2Subdevice::formats(unsigned int pad)
>  			return {};
>  
>  		if (formats.addFormat(code, sizes)) {
> -			LOG(V4L2Subdev, Error)
> +			LOG(V4L2, Error)
>  				<< "Could not add sizes for media bus code "
>  				<< code << " on pad " << pad;
>  			return {};
> @@ -232,10 +194,9 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
>  	subdevFmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
>  	subdevFmt.pad = pad;
>  
> -	int ret = ioctl(fd_, VIDIOC_SUBDEV_G_FMT, &subdevFmt);
> +	int ret = ioctl(VIDIOC_SUBDEV_G_FMT, &subdevFmt);
>  	if (ret) {
> -		ret = -errno;
> -		LOG(V4L2Subdev, Error)
> +		LOG(V4L2, Error)
>  			<< "Unable to get format on pad " << pad
>  			<< ": " << strerror(-ret);
>  		return ret;
> @@ -268,10 +229,9 @@ int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format)
>  	subdevFmt.format.height = format->size.height;
>  	subdevFmt.format.code = format->mbus_code;
>  
> -	int ret = ioctl(fd_, VIDIOC_SUBDEV_S_FMT, &subdevFmt);
> +	int ret = ioctl(VIDIOC_SUBDEV_S_FMT, &subdevFmt);
>  	if (ret) {
> -		ret = -errno;
> -		LOG(V4L2Subdev, Error)
> +		LOG(V4L2, Error)
>  			<< "Unable to set format on pad " << pad
>  			<< ": " << strerror(-ret);
>  		return ret;
> @@ -305,11 +265,6 @@ V4L2Subdevice *V4L2Subdevice::fromEntityName(const MediaDevice *media,
>  	return new V4L2Subdevice(mediaEntity);
>  }
>  
> -std::string V4L2Subdevice::logPrefix() const
> -{
> -	return "'" + entity_->name() + "'";
> -}
> -
>  std::vector<unsigned int> V4L2Subdevice::enumPadCodes(unsigned int pad)
>  {
>  	std::vector<unsigned int> codes;
> @@ -321,18 +276,17 @@ std::vector<unsigned int> V4L2Subdevice::enumPadCodes(unsigned int pad)
>  		mbusEnum.index = index;
>  		mbusEnum.which = V4L2_SUBDEV_FORMAT_ACTIVE;
>  
> -		ret = ioctl(fd_, VIDIOC_SUBDEV_ENUM_MBUS_CODE, &mbusEnum);
> +		ret = ioctl(VIDIOC_SUBDEV_ENUM_MBUS_CODE, &mbusEnum);
>  		if (ret)
>  			break;
>  
>  		codes.push_back(mbusEnum.code);
>  	}
>  
> -	if (ret && errno != EINVAL) {
> -		ret = errno;
> -		LOG(V4L2Subdev, Error)
> +	if (ret < 0 && ret != -EINVAL) {
> +		LOG(V4L2, Error)
>  			<< "Unable to enumerate formats on pad " << pad
> -			<< ": " << strerror(ret);
> +			<< ": " << strerror(-ret);
>  		return {};
>  	}
>  
> @@ -352,7 +306,7 @@ std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
>  		sizeEnum.code = code;
>  		sizeEnum.which = V4L2_SUBDEV_FORMAT_ACTIVE;
>  
> -		ret = ioctl(fd_, VIDIOC_SUBDEV_ENUM_FRAME_SIZE, &sizeEnum);
> +		ret = ioctl(VIDIOC_SUBDEV_ENUM_FRAME_SIZE, &sizeEnum);
>  		if (ret)
>  			break;
>  
> @@ -360,9 +314,8 @@ std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
>  				   sizeEnum.max_width, sizeEnum.max_height);
>  	}
>  
> -	if (ret && (errno != EINVAL && errno != ENOTTY)) {
> -		ret = -errno;
> -		LOG(V4L2Subdev, Error)
> +	if (ret < 0 && ret != -EINVAL && ret != -ENOTTY) {
> +		LOG(V4L2, Error)
>  			<< "Unable to enumerate sizes on pad " << pad
>  			<< ": " << strerror(-ret);
>  		return {};
> @@ -386,10 +339,9 @@ int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
>  	sel.r.width = rect->w;
>  	sel.r.height = rect->h;
>  
> -	int ret = ioctl(fd_, VIDIOC_SUBDEV_S_SELECTION, &sel);
> +	int ret = ioctl(VIDIOC_SUBDEV_S_SELECTION, &sel);
>  	if (ret < 0) {
> -		ret = -errno;
> -		LOG(V4L2Subdev, Error)
> +		LOG(V4L2, Error)
>  			<< "Unable to set rectangle " << target << " on pad "
>  			<< pad << ": " << strerror(-ret);
>  		return ret;
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index 0e70498c8bb1..403e0b2e0653 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -30,7 +30,7 @@
>   */
>  namespace libcamera {
>  
> -LOG_DEFINE_CATEGORY(V4L2)
> +LOG_DECLARE_CATEGORY(V4L2)
>  
>  /**
>   * \struct V4L2Capability
> @@ -270,7 +270,7 @@ const std::string V4L2DeviceFormat::toString() const
>   * \param[in] deviceNode The file-system path to the video device node
>   */
>  V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
> -	: deviceNode_(deviceNode), fd_(-1), bufferPool_(nullptr),
> +	: V4L2Device(deviceNode, deviceNode), bufferPool_(nullptr),
>  	  queuedBuffersCount_(0), fdEvent_(nullptr)
>  {
>  	/*
> @@ -305,23 +305,12 @@ int V4L2VideoDevice::open()
>  {
>  	int ret;
>  
> -	if (isOpen()) {
> -		LOG(V4L2, Error) << "Device already open";
> -		return -EBUSY;
> -	}
> -
> -	ret = ::open(deviceNode_.c_str(), O_RDWR | O_NONBLOCK);
> -	if (ret < 0) {
> -		ret = -errno;
> -		LOG(V4L2, Error)
> -			<< "Failed to open V4L2 device: " << strerror(-ret);
> +	ret = V4L2Device::open(O_RDWR | O_NONBLOCK);
> +	if (ret < 0)
>  		return ret;
> -	}
> -	fd_ = ret;
>  
> -	ret = ioctl(fd_, VIDIOC_QUERYCAP, &caps_);
> +	ret = ioctl(VIDIOC_QUERYCAP, &caps_);
>  	if (ret < 0) {
> -		ret = -errno;
>  		LOG(V4L2, Error)
>  			<< "Failed to query device capabilities: "
>  			<< strerror(-ret);
> @@ -342,20 +331,20 @@ int V4L2VideoDevice::open()
>  	 * (POLLIN), and write notifications for OUTPUT devices (POLLOUT).
>  	 */
>  	if (caps_.isVideoCapture()) {
> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Read);
> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Read);
>  		bufferType_ = caps_.isMultiplanar()
>  			    ? V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE
>  			    : V4L2_BUF_TYPE_VIDEO_CAPTURE;
>  	} else if (caps_.isVideoOutput()) {
> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Write);
> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Write);
>  		bufferType_ = caps_.isMultiplanar()
>  			    ? V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE
>  			    : V4L2_BUF_TYPE_VIDEO_OUTPUT;
>  	} else if (caps_.isMetaCapture()) {
> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Read);
> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Read);
>  		bufferType_ = V4L2_BUF_TYPE_META_CAPTURE;
>  	} else if (caps_.isMetaOutput()) {
> -		fdEvent_ = new EventNotifier(fd_, EventNotifier::Write);
> +		fdEvent_ = new EventNotifier(fd(), EventNotifier::Write);
>  		bufferType_ = V4L2_BUF_TYPE_META_OUTPUT;
>  	} else {
>  		LOG(V4L2, Error) << "Device is not a supported type";
> @@ -368,28 +357,18 @@ int V4L2VideoDevice::open()
>  	return 0;
>  }
>  
> -/**
> - * \brief Check if device is successfully opened
> - * \return True if the device is open, false otherwise
> - */
> -bool V4L2VideoDevice::isOpen() const
> -{
> -	return fd_ != -1;
> -}
> -
>  /**
>   * \brief Close the device, releasing any resources acquired by open()
>   */
>  void V4L2VideoDevice::close()
>  {
> -	if (fd_ < 0)
> +	if (!isOpen())
>  		return;
>  
>  	releaseBuffers();
>  	delete fdEvent_;
>  
> -	::close(fd_);
> -	fd_ = -1;
> +	V4L2Device::close();
>  }
>  
>  /**
> @@ -410,17 +389,6 @@ void V4L2VideoDevice::close()
>   * \return The string containing the device location
>   */
>  
> -/**
> - * \fn V4L2VideoDevice::deviceNode()
> - * \brief Retrieve the video device node path
> - * \return The video device device node path
> - */
> -
> -std::string V4L2VideoDevice::logPrefix() const
> -{
> -	return deviceNode_ + (V4L2_TYPE_IS_OUTPUT(bufferType_) ? "[out]" : "[cap]");
> -}
> -
>  /**
>   * \brief Retrieve the image format set on the V4L2 device
>   * \param[out] format The image format applied on the device
> @@ -462,9 +430,8 @@ int V4L2VideoDevice::getFormatMeta(V4L2DeviceFormat *format)
>  	int ret;
>  
>  	v4l2Format.type = bufferType_;
> -	ret = ioctl(fd_, VIDIOC_G_FMT, &v4l2Format);
> +	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
>  	if (ret) {
> -		ret = -errno;
>  		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
>  		return ret;
>  	}
> @@ -488,9 +455,8 @@ int V4L2VideoDevice::setFormatMeta(V4L2DeviceFormat *format)
>  	v4l2Format.type = bufferType_;
>  	pix->dataformat = format->fourcc;
>  	pix->buffersize = format->planes[0].size;
> -	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
> +	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
>  	if (ret) {
> -		ret = -errno;
>  		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
>  		return ret;
>  	}
> @@ -516,9 +482,8 @@ int V4L2VideoDevice::getFormatMultiplane(V4L2DeviceFormat *format)
>  	int ret;
>  
>  	v4l2Format.type = bufferType_;
> -	ret = ioctl(fd_, VIDIOC_G_FMT, &v4l2Format);
> +	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
>  	if (ret) {
> -		ret = -errno;
>  		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
>  		return ret;
>  	}
> @@ -554,9 +519,8 @@ int V4L2VideoDevice::setFormatMultiplane(V4L2DeviceFormat *format)
>  		pix->plane_fmt[i].sizeimage = format->planes[i].size;
>  	}
>  
> -	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
> +	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
>  	if (ret) {
> -		ret = -errno;
>  		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
>  		return ret;
>  	}
> @@ -584,9 +548,8 @@ int V4L2VideoDevice::getFormatSingleplane(V4L2DeviceFormat *format)
>  	int ret;
>  
>  	v4l2Format.type = bufferType_;
> -	ret = ioctl(fd_, VIDIOC_G_FMT, &v4l2Format);
> +	ret = ioctl(VIDIOC_G_FMT, &v4l2Format);
>  	if (ret) {
> -		ret = -errno;
>  		LOG(V4L2, Error) << "Unable to get format: " << strerror(-ret);
>  		return ret;
>  	}
> @@ -613,9 +576,8 @@ int V4L2VideoDevice::setFormatSingleplane(V4L2DeviceFormat *format)
>  	pix->pixelformat = format->fourcc;
>  	pix->bytesperline = format->planes[0].bpl;
>  	pix->field = V4L2_FIELD_NONE;
> -	ret = ioctl(fd_, VIDIOC_S_FMT, &v4l2Format);
> +	ret = ioctl(VIDIOC_S_FMT, &v4l2Format);
>  	if (ret) {
> -		ret = -errno;
>  		LOG(V4L2, Error) << "Unable to set format: " << strerror(-ret);
>  		return ret;
>  	}
> @@ -670,9 +632,8 @@ int V4L2VideoDevice::requestBuffers(unsigned int count)
>  	rb.type = bufferType_;
>  	rb.memory = memoryType_;
>  
> -	ret = ioctl(fd_, VIDIOC_REQBUFS, &rb);
> +	ret = ioctl(VIDIOC_REQBUFS, &rb);
>  	if (ret < 0) {
> -		ret = -errno;
>  		LOG(V4L2, Error)
>  			<< "Unable to request " << count << " buffers: "
>  			<< strerror(-ret);
> @@ -722,9 +683,8 @@ int V4L2VideoDevice::exportBuffers(BufferPool *pool)
>  		buf.length = VIDEO_MAX_PLANES;
>  		buf.m.planes = planes;
>  
> -		ret = ioctl(fd_, VIDIOC_QUERYBUF, &buf);
> +		ret = ioctl(VIDIOC_QUERYBUF, &buf);
>  		if (ret < 0) {
> -			ret = -errno;
>  			LOG(V4L2, Error)
>  				<< "Unable to query buffer " << i << ": "
>  				<< strerror(-ret);
> @@ -775,9 +735,8 @@ int V4L2VideoDevice::createPlane(Buffer *buffer, unsigned int planeIndex,
>  	expbuf.plane = planeIndex;
>  	expbuf.flags = O_RDWR;
>  
> -	ret = ioctl(fd_, VIDIOC_EXPBUF, &expbuf);
> +	ret = ioctl(VIDIOC_EXPBUF, &expbuf);
>  	if (ret < 0) {
> -		ret = -errno;
>  		LOG(V4L2, Error)
>  			<< "Failed to export buffer: " << strerror(-ret);
>  		return ret;
> @@ -801,15 +760,14 @@ std::vector<unsigned int> V4L2VideoDevice::enumPixelformats()
>  		pixelformatEnum.index = index;
>  		pixelformatEnum.type = bufferType_;
>  
> -		ret = ioctl(fd_, VIDIOC_ENUM_FMT, &pixelformatEnum);
> +		ret = ioctl(VIDIOC_ENUM_FMT, &pixelformatEnum);
>  		if (ret)
>  			break;
>  
>  		formats.push_back(pixelformatEnum.pixelformat);
>  	}
>  
> -	if (ret && errno != EINVAL) {
> -		ret = -errno;
> +	if (ret && ret != -EINVAL) {
>  		LOG(V4L2, Error)
>  			<< "Unable to enumerate pixel formats: "
>  			<< strerror(-ret);
> @@ -829,7 +787,7 @@ std::vector<SizeRange> V4L2VideoDevice::enumSizes(unsigned int pixelFormat)
>  		frameSize.index = index;
>  		frameSize.pixel_format = pixelFormat;
>  
> -		ret = ioctl(fd_, VIDIOC_ENUM_FRAMESIZES, &frameSize);
> +		ret = ioctl(VIDIOC_ENUM_FRAMESIZES, &frameSize);
>  		if (ret)
>  			break;
>  
> @@ -867,8 +825,7 @@ std::vector<SizeRange> V4L2VideoDevice::enumSizes(unsigned int pixelFormat)
>  		}
>  	}
>  
> -	if (ret && errno != EINVAL) {
> -		ret = -errno;
> +	if (ret && ret != -EINVAL) {
>  		LOG(V4L2, Error)
>  			<< "Unable to enumerate frame sizes: "
>  			<< strerror(-ret);
> @@ -969,9 +926,8 @@ int V4L2VideoDevice::queueBuffer(Buffer *buffer)
>  
>  	LOG(V4L2, Debug) << "Queueing buffer " << buf.index;
>  
> -	ret = ioctl(fd_, VIDIOC_QBUF, &buf);
> +	ret = ioctl(VIDIOC_QBUF, &buf);
>  	if (ret < 0) {
> -		ret = -errno;
>  		LOG(V4L2, Error)
>  			<< "Failed to queue buffer " << buf.index << ": "
>  			<< strerror(-ret);
> @@ -1006,9 +962,8 @@ Buffer *V4L2VideoDevice::dequeueBuffer()
>  		buf.m.planes = planes;
>  	}
>  
> -	ret = ioctl(fd_, VIDIOC_DQBUF, &buf);
> +	ret = ioctl(VIDIOC_DQBUF, &buf);
>  	if (ret < 0) {
> -		ret = -errno;
>  		LOG(V4L2, Error)
>  			<< "Failed to dequeue buffer: " << strerror(-ret);
>  		return nullptr;
> @@ -1066,9 +1021,8 @@ int V4L2VideoDevice::streamOn()
>  {
>  	int ret;
>  
> -	ret = ioctl(fd_, VIDIOC_STREAMON, &bufferType_);
> +	ret = ioctl(VIDIOC_STREAMON, &bufferType_);
>  	if (ret < 0) {
> -		ret = -errno;
>  		LOG(V4L2, Error)
>  			<< "Failed to start streaming: " << strerror(-ret);
>  		return ret;
> @@ -1089,9 +1043,8 @@ int V4L2VideoDevice::streamOff()
>  {
>  	int ret;
>  
> -	ret = ioctl(fd_, VIDIOC_STREAMOFF, &bufferType_);
> +	ret = ioctl(VIDIOC_STREAMOFF, &bufferType_);
>  	if (ret < 0) {
> -		ret = -errno;
>  		LOG(V4L2, Error)
>  			<< "Failed to stop streaming: " << strerror(-ret);
>  		return ret;

-- 
Regards,

Laurent Pinchart


More information about the libcamera-devel mailing list