| Message ID | 20200728234225.3505868-1-niklas.soderlund@ragnatech.se |
|---|---|
| State | Superseded |
| Headers | show |
| Series |
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| Related | show |
Hi Niklas, On Wed, Jul 29, 2020 at 01:42:21AM +0200, Niklas Söderlund wrote: > Add a method to lookup a V4L2 devices path in sysfs. > > Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> > --- > include/libcamera/internal/v4l2_device.h | 1 + > src/libcamera/v4l2_device.cpp | 24 ++++++++++++++++++++++++ > 2 files changed, 25 insertions(+) > > diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h > index bf643f2ec966bb33..3b605aab343b3b94 100644 > --- a/include/libcamera/internal/v4l2_device.h > +++ b/include/libcamera/internal/v4l2_device.h > @@ -30,6 +30,7 @@ public: > int setControls(ControlList *ctrls); > > const std::string &deviceNode() const { return deviceNode_; } > + std::string devicePath() const; > > protected: > V4L2Device(const std::string &deviceNode); > diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp > index 56ea1ddda2c1425f..c186f246dbfaff66 100644 > --- a/src/libcamera/v4l2_device.cpp > +++ b/src/libcamera/v4l2_device.cpp > @@ -9,6 +9,7 @@ > > #include <fcntl.h> > #include <iomanip> > +#include <limits.h> > #include <string.h> > #include <sys/ioctl.h> > #include <sys/syscall.h> > @@ -350,6 +351,29 @@ int V4L2Device::setControls(ControlList *ctrls) > return ret; > } > > +/** > + * \brief Retrieve the device path "the device path in sysfs" or "under /sys" not sure which one is the most correct one. But I think it's worth pointing it out as when I read "the device path" I thought about the device node path in /dev/ > + * > + * The device path describes the device backing the V4L2 device. same > + * > + * \todo When switching to C++17 use std::filesystem:: in the implementation. > + * \todo Query udev for this information as the path created for vdev here > + * migh not be correct. > + * > + * \return The device path same here > + */ > +std::string V4L2Device::devicePath() const > +{ > + std::string vdev = basename(deviceNode_.c_str()); > + std::string sysfs = "/sys/class/video4linux/" + vdev + "/device"; > + > + char path[PATH_MAX]; > + if (!realpath(sysfs.c_str(), path)) > + LOG(V4L2, Fatal) << "Can not resolve path for " << deviceNode_; > + > + return path; > +} > + I think Laurent had a comment suggesting to have this go through the device enumerator sub-classes. I can't tell why both him and you say that "the path here might not be correct", so I'll just re-state his comment here. From my side Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Thanks j > /** > * \brief Perform an IOCTL system call on the device node > * \param[in] request The IOCTL request code > -- > 2.27.0 > > _______________________________________________ > libcamera-devel mailing list > libcamera-devel@lists.libcamera.org > https://lists.libcamera.org/listinfo/libcamera-devel
diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h index bf643f2ec966bb33..3b605aab343b3b94 100644 --- a/include/libcamera/internal/v4l2_device.h +++ b/include/libcamera/internal/v4l2_device.h @@ -30,6 +30,7 @@ public: int setControls(ControlList *ctrls); const std::string &deviceNode() const { return deviceNode_; } + std::string devicePath() const; protected: V4L2Device(const std::string &deviceNode); diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp index 56ea1ddda2c1425f..c186f246dbfaff66 100644 --- a/src/libcamera/v4l2_device.cpp +++ b/src/libcamera/v4l2_device.cpp @@ -9,6 +9,7 @@ #include <fcntl.h> #include <iomanip> +#include <limits.h> #include <string.h> #include <sys/ioctl.h> #include <sys/syscall.h> @@ -350,6 +351,29 @@ int V4L2Device::setControls(ControlList *ctrls) return ret; } +/** + * \brief Retrieve the device path + * + * The device path describes the device backing the V4L2 device. + * + * \todo When switching to C++17 use std::filesystem:: in the implementation. + * \todo Query udev for this information as the path created for vdev here + * migh not be correct. + * + * \return The device path + */ +std::string V4L2Device::devicePath() const +{ + std::string vdev = basename(deviceNode_.c_str()); + std::string sysfs = "/sys/class/video4linux/" + vdev + "/device"; + + char path[PATH_MAX]; + if (!realpath(sysfs.c_str(), path)) + LOG(V4L2, Fatal) << "Can not resolve path for " << deviceNode_; + + return path; +} + /** * \brief Perform an IOCTL system call on the device node * \param[in] request The IOCTL request code
Add a method to lookup a V4L2 devices path in sysfs. Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> --- include/libcamera/internal/v4l2_device.h | 1 + src/libcamera/v4l2_device.cpp | 24 ++++++++++++++++++++++++ 2 files changed, 25 insertions(+)