From 79ab0e925a782a6781d38237435fcfc29ddd2e20 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 26 Apr 2020 02:08:37 +0300 Subject: libcamera: v4l2_device: Simplify usage of getControls() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The V4L2Device::getControls() function takes a ControlList that needs to be pre-populated with dummy entries for the controls that need to be read. This is a cumbersome API, especially when reading a single control. Make it nicer by passing the list of V4L2 controls as a vector of control IDs, and returning a ControlList. Signed-off-by: Laurent Pinchart Reviewed-by: Jacopo Mondi Reviewed-by: Niklas Söderlund --- src/libcamera/v4l2_device.cpp | 60 ++++++++++++++++++++++++------------------- 1 file changed, 33 insertions(+), 27 deletions(-) (limited to 'src/libcamera/v4l2_device.cpp') diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp index c134266e..d08ab531 100644 --- a/src/libcamera/v4l2_device.cpp +++ b/src/libcamera/v4l2_device.cpp @@ -147,46 +147,51 @@ void V4L2Device::close() /** * \brief Read controls from the device - * \param[inout] ctrls The list of controls to read + * \param[in] ids The list of controls to read, specified by their ID * - * This method reads the value of all controls contained in \a ctrls, and stores - * their values in the corresponding \a ctrls entry. + * This method reads the value of all controls contained in \a ids, and returns + * their values as a ControlList. * - * If any control in \a ctrls is not supported by the device, is disabled (i.e. + * If any control in \a ids is not supported by the device, is disabled (i.e. * has the V4L2_CTRL_FLAG_DISABLED flag set), 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. + * method returns an empty control list. * - * \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 + * \return The control values in a ControlList on success, or an empty list on + * error */ -int V4L2Device::getControls(ControlList *ctrls) +ControlList V4L2Device::getControls(const std::vector &ids) { - unsigned int count = ctrls->size(); + unsigned int count = ids.size(); if (count == 0) - return 0; + return {}; - struct v4l2_ext_control v4l2Ctrls[count]; - memset(v4l2Ctrls, 0, sizeof(v4l2Ctrls)); + ControlList ctrls{ controls_ }; - unsigned int i = 0; - for (auto &ctrl : *ctrls) { - unsigned int id = ctrl.first; + /* + * Start by filling the ControlList. This can't be combined with filling + * v4l2Ctrls, as updateControls() relies on both containers having the + * same order, and the control list is based on a map, which is not + * sorted by insertion order. + */ + for (uint32_t id : ids) { const auto iter = controls_.find(id); if (iter == controls_.end()) { LOG(V4L2, Error) << "Control " << utils::hex(id) << " not found"; - return -EINVAL; + return {}; } + ctrls.set(id, {}); + } + + struct v4l2_ext_control v4l2Ctrls[count]; + memset(v4l2Ctrls, 0, sizeof(v4l2Ctrls)); + + unsigned int i = 0; + for (auto &ctrl : ctrls) { + unsigned int id = ctrl.first; const struct v4l2_query_ext_ctrl &info = controlInfo_[id]; - ControlValue &value = ctrl.second; if (info.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD) { ControlType type; @@ -200,9 +205,10 @@ int V4L2Device::getControls(ControlList *ctrls) LOG(V4L2, Error) << "Unsupported payload control type " << info.type; - return -EINVAL; + return {}; } + ControlValue &value = ctrl.second; value.reserve(type, true, info.elems); Span data = value.data(); @@ -227,7 +233,7 @@ int V4L2Device::getControls(ControlList *ctrls) if (errorIdx == 0 || errorIdx >= count) { LOG(V4L2, Error) << "Unable to read controls: " << strerror(-ret); - return -EINVAL; + return {}; } /* A specific control failed. */ @@ -237,9 +243,9 @@ int V4L2Device::getControls(ControlList *ctrls) ret = errorIdx; } - updateControls(ctrls, v4l2Ctrls, count); + updateControls(&ctrls, v4l2Ctrls, count); - return ret; + return ctrls; } /** -- cgit v1.2.1