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-rw-r--r--src/libcamera/include/v4l2_device.h9
-rw-r--r--src/libcamera/v4l2_device.cpp190
2 files changed, 199 insertions, 0 deletions
diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
index 55696046..24a0134a 100644
--- a/src/libcamera/include/v4l2_device.h
+++ b/src/libcamera/include/v4l2_device.h
@@ -10,11 +10,14 @@
#include <map>
#include <string>
+#include <linux/videodev2.h>
+
#include "log.h"
namespace libcamera {
class V4L2ControlInfo;
+class V4L2ControlList;
class V4L2Device : protected Loggable
{
@@ -23,6 +26,8 @@ public:
bool isOpen() const { return fd_ != -1; }
const V4L2ControlInfo *getControlInfo(unsigned int id) const;
+ int getControls(V4L2ControlList *ctrls);
+ int setControls(V4L2ControlList *ctrls);
const std::string &deviceNode() const { return deviceNode_; }
@@ -38,6 +43,10 @@ protected:
private:
void listControls();
+ void updateControls(V4L2ControlList *ctrls,
+ const V4L2ControlInfo **controlInfo,
+ const struct v4l2_ext_control *v4l2Ctrls,
+ unsigned int count);
std::map<unsigned int, V4L2ControlInfo> controls_;
std::string deviceNode_;
diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index 51764b44..84758a81 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -126,6 +126,163 @@ const V4L2ControlInfo *V4L2Device::getControlInfo(unsigned int id) const
}
/**
+ * \brief Read controls from the device
+ * \param[inout] ctrls The list of controls to read
+ *
+ * This method reads the value of all controls contained in \a ctrls, and stores
+ * their values in the corresponding \a ctrls entry.
+ *
+ * If any control in \a ctrls is not supported by the device, is disabled (i.e.
+ * has the V4L2_CTRL_FLAG_DISABLED flag set), is a compound control, or if any
+ * other error occurs during validation of the requested controls, no control is
+ * read and this method returns -EINVAL.
+ *
+ * If an error occurs while reading the controls, the index of the first control
+ * that couldn't be read is returned. The value of all controls below that index
+ * are updated in \a ctrls, while the value of all the other controls are not
+ * changed.
+ *
+ * \return 0 on success or an error code otherwise
+ * \retval -EINVAL One of the control is not supported or not accessible
+ * \retval i The index of the control that failed
+ */
+int V4L2Device::getControls(V4L2ControlList *ctrls)
+{
+ unsigned int count = ctrls->size();
+ if (count == 0)
+ return 0;
+
+ const V4L2ControlInfo *controlInfo[count] = {};
+ struct v4l2_ext_control v4l2Ctrls[count] = {};
+ for (unsigned int i = 0; i < count; ++i) {
+ const V4L2Control *ctrl = ctrls->getByIndex(i);
+ const V4L2ControlInfo *info = getControlInfo(ctrl->id());
+ if (!info) {
+ LOG(V4L2, Error)
+ << "Control '" << ctrl->id() << "' not found";
+ return -EINVAL;
+ }
+
+ controlInfo[i] = info;
+ v4l2Ctrls[i].id = info->id();
+ }
+
+ struct v4l2_ext_controls v4l2ExtCtrls = {};
+ v4l2ExtCtrls.which = V4L2_CTRL_WHICH_CUR_VAL;
+ v4l2ExtCtrls.controls = v4l2Ctrls;
+ v4l2ExtCtrls.count = count;
+
+ int ret = ioctl(VIDIOC_G_EXT_CTRLS, &v4l2ExtCtrls);
+ if (ret) {
+ unsigned int errorIdx = v4l2ExtCtrls.error_idx;
+
+ /* Generic validation error. */
+ if (errorIdx == 0 || errorIdx >= count) {
+ LOG(V4L2, Error) << "Unable to read controls: "
+ << strerror(ret);
+ return -EINVAL;
+ }
+
+ /* A specific control failed. */
+ LOG(V4L2, Error) << "Unable to read control " << errorIdx
+ << ": " << strerror(ret);
+ count = errorIdx - 1;
+ ret = errorIdx;
+ }
+
+ updateControls(ctrls, controlInfo, v4l2Ctrls, count);
+
+ return ret;
+}
+
+/**
+ * \brief Write controls to the device
+ * \param[in] ctrls The list of controls to write
+ *
+ * This method writes the value of all controls contained in \a ctrls, and
+ * stores the values actually applied to the device in the corresponding
+ * \a ctrls entry.
+ *
+ * If any control in \a ctrls is not supported by the device, is disabled (i.e.
+ * has the V4L2_CTRL_FLAG_DISABLED flag set), is read-only, is a
+ * compound control, or if any other error occurs during validation of
+ * the requested controls, no control is written and this method returns
+ * -EINVAL.
+ *
+ * If an error occurs while writing the controls, the index of the first
+ * control that couldn't be written is returned. All controls below that index
+ * are written and their values are updated in \a ctrls, while all other
+ * controls are not written and their values are not changed.
+ *
+ * \return 0 on success or an error code otherwise
+ * \retval -EINVAL One of the control is not supported or not accessible
+ * \retval i The index of the control that failed
+ */
+int V4L2Device::setControls(V4L2ControlList *ctrls)
+{
+ unsigned int count = ctrls->size();
+ if (count == 0)
+ return 0;
+
+ const V4L2ControlInfo *controlInfo[count] = {};
+ struct v4l2_ext_control v4l2Ctrls[count] = {};
+
+ for (unsigned int i = 0; i < count; ++i) {
+ const V4L2Control *ctrl = ctrls->getByIndex(i);
+ const V4L2ControlInfo *info = getControlInfo(ctrl->id());
+ if (!info) {
+ LOG(V4L2, Error)
+ << "Control '" << ctrl->id() << "' not found";
+ return -EINVAL;
+ }
+
+ controlInfo[i] = info;
+ v4l2Ctrls[i].id = info->id();
+
+ /* Set the v4l2_ext_control value for the write operation. */
+ switch (info->type()) {
+ case V4L2_CTRL_TYPE_INTEGER64:
+ v4l2Ctrls[i].value64 = ctrl->value();
+ break;
+ default:
+ /*
+ * \todo To be changed when support for string and
+ * compound controls will be added.
+ */
+ v4l2Ctrls[i].value = ctrl->value();
+ break;
+ }
+ }
+
+ struct v4l2_ext_controls v4l2ExtCtrls = {};
+ v4l2ExtCtrls.which = V4L2_CTRL_WHICH_CUR_VAL;
+ v4l2ExtCtrls.controls = v4l2Ctrls;
+ v4l2ExtCtrls.count = count;
+
+ int ret = ioctl(VIDIOC_S_EXT_CTRLS, &v4l2ExtCtrls);
+ if (ret) {
+ unsigned int errorIdx = v4l2ExtCtrls.error_idx;
+
+ /* Generic validation error. */
+ if (errorIdx == 0 || errorIdx >= count) {
+ LOG(V4L2, Error) << "Unable to read controls: "
+ << strerror(ret);
+ return -EINVAL;
+ }
+
+ /* A specific control failed. */
+ LOG(V4L2, Error) << "Unable to read control " << errorIdx
+ << ": " << strerror(ret);
+ count = errorIdx - 1;
+ ret = errorIdx;
+ }
+
+ updateControls(ctrls, controlInfo, v4l2Ctrls, count);
+
+ return ret;
+}
+
+/**
* \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
@@ -194,4 +351,37 @@ void V4L2Device::listControls()
}
}
+/*
+ * \brief Update the value of the first \a count V4L2 controls in \a ctrls using
+ * values in \a v4l2Ctrls
+ * \param[inout] ctrls List of V4L2 controls to update
+ * \param[in] controlInfo List of V4L2 control information
+ * \param[in] v4l2Ctrls List of V4L2 extended controls as returned by the driver
+ * \param[in] count The number of controls to update
+ */
+void V4L2Device::updateControls(V4L2ControlList *ctrls,
+ const V4L2ControlInfo **controlInfo,
+ const struct v4l2_ext_control *v4l2Ctrls,
+ unsigned int count)
+{
+ for (unsigned int i = 0; i < count; ++i) {
+ const struct v4l2_ext_control *v4l2Ctrl = &v4l2Ctrls[i];
+ const V4L2ControlInfo *info = controlInfo[i];
+ V4L2Control *ctrl = ctrls->getByIndex(i);
+
+ switch (info->type()) {
+ case V4L2_CTRL_TYPE_INTEGER64:
+ ctrl->setValue(v4l2Ctrl->value64);
+ break;
+ default:
+ /*
+ * \todo To be changed when support for string and
+ * compound controls will be added.
+ */
+ ctrl->setValue(v4l2Ctrl->value);
+ break;
+ }
+ }
+}
+
} /* namespace libcamera */
generated by cgit v1.2.1 (git 2.18.0) at 2024-11-10 08:14:24 +0000