[libcamera-devel] [PATCH v6 2/6] libcamera: v4l2_device: List valid controls at open

[Laurent Pinchart]

Hi Jacopo,

Thank you for the patch.

On Mon, Jun 24, 2019 at 04:28:55PM +0200, Jacopo Mondi wrote:
> Enumerate all the valid controls a device supports at open() time.
> A control is valid only if its type is supported.
> 
> Store the control information in a map inside the device to save
> querying the control when setting or getting its value from the device
> and provide an operation to retrieve information by control ID.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> ---
>  src/libcamera/include/v4l2_device.h |  8 ++++
>  src/libcamera/v4l2_device.cpp       | 57 +++++++++++++++++++++++++++++
>  2 files changed, 65 insertions(+)
> 
> diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
> index 75f23a05b903..556960467e10 100644
> --- a/src/libcamera/include/v4l2_device.h
> +++ b/src/libcamera/include/v4l2_device.h
> @@ -7,18 +7,23 @@
>  #ifndef __LIBCAMERA_V4L2_DEVICE_H__
>  #define __LIBCAMERA_V4L2_DEVICE_H__
>  
> +#include <map>
>  #include <string>
>  
>  #include "log.h"
>  
>  namespace libcamera {
>  
> +class V4L2ControlInfo;
> +
>  class V4L2Device : protected Loggable
>  {
>  public:
>  	void close();
>  	bool isOpen() const { return fd_ != -1; }
>  
> +	const V4L2ControlInfo *getControlInfo(unsigned int id) const;
> +
>  	const std::string &deviceNode() const { return deviceNode_; }
>  
>  protected:
> @@ -32,6 +37,9 @@ protected:
>  	int fd() { return fd_; }
>  
>  private:
> +	void listControls();
> +
> +	std::map<unsigned int, V4L2ControlInfo> controls_;
>  	std::string deviceNode_;
>  	int fd_;
>  };
> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> index 99621a724b96..51764b441f92 100644
> --- a/src/libcamera/v4l2_device.cpp
> +++ b/src/libcamera/v4l2_device.cpp
> @@ -13,6 +13,7 @@
>  #include <unistd.h>
>  
>  #include "log.h"
> +#include "v4l2_controls.h"
>  
>  /**
>   * \file v4l2_device.h
> @@ -82,6 +83,8 @@ int V4L2Device::open(unsigned int flags)
>  
>  	fd_ = ret;
>  
> +	listControls();
> +
>  	return 0;
>  }
>  
> @@ -107,6 +110,21 @@ void V4L2Device::close()
>   * \return True if the V4L2 device node is open, false otherwise
>   */
>  
> +/**
> + * \brief Retrieve information about a control
> + * \param[in] id The control ID
> + * \return A pointer to the V4L2ControlInfo for control \a id, or nullptr
> + * if the device doesn't have such a control
> + */
> +const V4L2ControlInfo *V4L2Device::getControlInfo(unsigned int id) const
> +{
> +	auto it = controls_.find(id);
> +	if (it == controls_.end())
> +		return nullptr;
> +
> +	return &it->second;
> +}
> +
>  /**
>   * \brief Perform an IOCTL system call on the device node
>   * \param[in] request The IOCTL request code
> @@ -137,4 +155,43 @@ int V4L2Device::ioctl(unsigned long request, void *argp)
>   * \return The V4L2 device file descriptor, -1 if the device node is not open
>   */
>  
> +/*
> + * \brief List and store information about all controls supported by the
> + * V4L2 device
> + */
> +void V4L2Device::listControls()
> +{
> +	struct v4l2_query_ext_ctrl ctrl = {};
> +
> +	/* \todo Add support for menu and compound controls. */
> +	ctrl.id = V4L2_CTRL_FLAG_NEXT_CTRL;
> +	while (ioctl(VIDIOC_QUERY_EXT_CTRL, &ctrl) == 0) {
> +		if (ctrl.type == V4L2_CTRL_TYPE_CTRL_CLASS ||
> +		    ctrl.flags & V4L2_CTRL_FLAG_DISABLED) {
> +			ctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
> +			continue;
> +		}
> +
> +		V4L2ControlInfo info(ctrl);
> +		switch (info.type()) {
> +		case V4L2_CTRL_TYPE_INTEGER:
> +		case V4L2_CTRL_TYPE_BOOLEAN:
> +		case V4L2_CTRL_TYPE_MENU:
> +		case V4L2_CTRL_TYPE_BUTTON:
> +		case V4L2_CTRL_TYPE_INTEGER64:
> +		case V4L2_CTRL_TYPE_BITMASK:
> +		case V4L2_CTRL_TYPE_INTEGER_MENU:
> +			break;
> +		/* \todo Support compound controls. */
> +		default:
> +			LOG(V4L2, Error) << "Control type '" << info.type()
> +					 << "' not supported";
> +			continue;
> +		}
> +
> +		controls_.emplace(ctrl.id, info);
> +		ctrl.id |= V4L2_CTRL_FLAG_NEXT_CTRL;
> +	}
> +}
> +
>  } /* namespace libcamera */

-- 
Regards,

Laurent Pinchart