[{"id":35837,"web_url":"https://patchwork.libcamera.org/comment/35837/","msgid":"<175802075894.103890.17224447851472181739@isaac-ThinkPad-T16-Gen-2>","date":"2025-09-16T11:05:58","subject":"Re: [PATCH v2 2/5] libcamera: Add support for camera flash devices","submitter":{"id":215,"url":"https://patchwork.libcamera.org/api/people/215/","name":"Isaac Scott","email":"isaac.scott@ideasonboard.com"},"content":"Hi Matthias,\n\nThank you for the patch!\n\nQuoting Matthias Fend (2025-09-12 08:13:21)\n> Add a class to model camera flash devices. Currently, only v4l2 flash\n> devices are supported. The v4l2 flash devices are implemented similar to\n> the camera lenses.\n> \n> Signed-off-by: Matthias Fend \n> ---\n> include/libcamera/internal/camera_flash.h | 72 ++++++++\n> include/libcamera/internal/camera_sensor.h | 2 +\n> src/libcamera/camera_flash.cpp | 249 ++++++++++++++++++++++++++\n> src/libcamera/meson.build | 1 +\n> src/libcamera/sensor/camera_sensor_legacy.cpp | 13 ++\n> src/libcamera/sensor/camera_sensor_raw.cpp | 13 ++\n> 6 files changed, 350 insertions(+)\n> \n> diff --git a/include/libcamera/internal/camera_flash.h b/include/libcamera/internal/camera_flash.h\n> new file mode 100644\n> index 0000000000000000000000000000000000000000..70234ca96d98dd88a084e2c6804a66e455d87ef8\n> --- /dev/null\n> +++ b/include/libcamera/internal/camera_flash.h\n> @@ -0,0 +1,72 @@\n> +/* SPDX-License-Identifier: LGPL-2.1-or-later */\n> +/*\n> + * Copyright (C) 2025, matthias.fend@emfend.at\n> + *\n> + * Camera flash support\n> + */\n> +#pragma once\n> +\n> +#include \n> +#include \n> +#include \n> +\n> +#include \n> +#include \n> +\n> +#include \n> +\n> +namespace libcamera {\n> +\n> +class MediaEntity;\n> +class V4L2Subdevice;\n> +\n> +class CameraFlash : protected Loggable\n> +{\n> +public:\n> + enum class Mode {\n> + None,\n> + Flash,\n> + Torch,\n> + };\n> +\n> + enum class StrobeSource {\n> + Software,\n> + External,\n> + };\n> +\n> + explicit CameraFlash(const MediaEntity *entity);\n> + ~CameraFlash();\n> + int init();\n> + std::optional getMode() const;\n> + int setMode(Mode mode);\n> + const ControlInfo &getFlashIntensityInfo() const;\n> + std::optional getFlashIntensity() const;\n> + int setFlashIntensity(int32_t intensity);\n> + const ControlInfo &getFlashTimeoutInfo() const;\n> + std::optional getFlashTimeout() const;\n> + int setFlashTimeout(int32_t timeout_us);\n> + std::optional getStrobeSource() const;\n> + int setStrobeSource(StrobeSource source);\n> + int startStrobe();\n> + int stopStrobe();\n> + const ControlInfo &getTorchIntensityInfo() const;\n> + std::optional getTorchIntensity() const;\n> + int setTorchIntensity(int32_t intensity);\n> +\n> +protected:\n> + std::string logPrefix() const override;\n> +\n> +private:\n> + LIBCAMERA_DISABLE_COPY_AND_MOVE(CameraFlash)\n> +\n> + std::optional getSubdevControl(uint32_t id) const;\n> + int setSubdevControl(uint32_t id, int32_t value);\n> + int validateDriver();\n> +\n> + const MediaEntity *entity_;\n> + std::unique_ptr subdev_;\n> + std::string model_;\n> + const ControlInfoMap *controlInfoMap_ = nullptr;\n> +};\n> +\n> +} /* namespace libcamera */\n> diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h\n> index f6ef4df170d43500bc652762e9a575010a6c1cbd..faeecf244c8d42a43eca52ae04813e0c2f80e516 100644\n> --- a/include/libcamera/internal/camera_sensor.h\n> +++ b/include/libcamera/internal/camera_sensor.h\n> @@ -28,6 +28,7 @@\n> \n> namespace libcamera {\n> \n> +class CameraFlash;\n> class CameraLens;\n> class MediaEntity;\n> class SensorConfiguration;\n> @@ -48,6 +49,7 @@ public:\n> virtual V4L2Subdevice *device() = 0;\n> \n> virtual CameraLens *focusLens() = 0;\n> + virtual CameraFlash *flash() = 0;\n> \n> virtual const std::vector &mbusCodes() const = 0;\n> virtual std::vector sizes(unsigned int mbusCode) const = 0;\n> diff --git a/src/libcamera/camera_flash.cpp b/src/libcamera/camera_flash.cpp\n> new file mode 100644\n> index 0000000000000000000000000000000000000000..d3b9fbf78f063ae0cb67635c4cda667508479534\n> --- /dev/null\n> +++ b/src/libcamera/camera_flash.cpp\n> @@ -0,0 +1,249 @@\n> +/* SPDX-License-Identifier: LGPL-2.1-or-later */\n> +/*\n> + * Copyright (C) 2025, matthias.fend@emfend.at\n> + *\n> + * Camera flash support\n> + */\n> +\n> +#include \"libcamera/internal/camera_flash.h\"\n> +\n> +#include \n> +\n> +#include \"libcamera/internal/v4l2_subdevice.h\"\n> +\n> +namespace libcamera {\n> +\n> +LOG_DEFINE_CATEGORY(CameraFlash)\n> +\n> +CameraFlash::CameraFlash(const MediaEntity *entity)\n> + : entity_(entity)\n> +{\n> +}\n> +\n> +CameraFlash::~CameraFlash() = default;\n> +\n> +int CameraFlash::init()\n> +{\n> + if (entity_->function() != MEDIA_ENT_F_FLASH) {\n> + LOG(CameraFlash, Error)\n> + << \"Invalid flash function \"\n> + << utils::hex(entity_->function());\n> + return -EINVAL;\n> + }\n> +\n> + subdev_ = std::make_unique(entity_);\n> + int ret = subdev_->open();\n> + if (ret < 0)\n> + return ret;\n> +\n> + controlInfoMap_ = &subdev_->controls();\n> +\n> + ret = validateDriver();\n> + if (ret)\n> + return ret;\n> +\n> + model_ = subdev_->model();\n> +\n> + return 0;\n> +}\n> +\n> +std::optional CameraFlash::getMode() const\n> +{\n> + Mode mode;\n> +\n> + auto v4l2Mode = getSubdevControl(V4L2_CID_FLASH_LED_MODE);\n> + if (!v4l2Mode)\n> + return std::nullopt;\n> +\n> + switch (*v4l2Mode) {\n> + case V4L2_FLASH_LED_MODE_FLASH:\n> + mode = Mode::Flash;\n> + break;\n> + case V4L2_FLASH_LED_MODE_TORCH:\n> + mode = Mode::Torch;\n> + break;\n> + case V4L2_FLASH_LED_MODE_NONE:\n> + default:\n> + mode = Mode::None;\n> + break;\n> + }\n> +\n> + return mode;\n> +}\n> +\n> +int CameraFlash::setMode(Mode mode)\n> +{\n> + int32_t v4l2Mode;\n> +\n> + switch (mode) {\n> + case Mode::Flash:\n> + v4l2Mode = V4L2_FLASH_LED_MODE_FLASH;\n> + break;\n> + case Mode::Torch:\n> + v4l2Mode = V4L2_FLASH_LED_MODE_TORCH;\n> + break;\n> + case Mode::None:\n> + v4l2Mode = V4L2_FLASH_LED_MODE_NONE;\n> + break;\n> + default:\n> + return -EINVAL;\n> + }\n> +\n> + return setSubdevControl(V4L2_CID_FLASH_LED_MODE, v4l2Mode);\n> +}\n> +\n> +const ControlInfo &CameraFlash::getFlashIntensityInfo() const\n> +{\n> + return controlInfoMap_->find(V4L2_CID_FLASH_INTENSITY)->second;\n> +}\n> +\n> +std::optional CameraFlash::getFlashIntensity() const\n> +{\n> + return getSubdevControl(V4L2_CID_FLASH_INTENSITY);\n> +}\n> +\n> +int CameraFlash::setFlashIntensity(int32_t intensity)\n> +{\n> + return setSubdevControl(V4L2_CID_FLASH_INTENSITY, intensity);\n> +}\n> +\n> +const ControlInfo &CameraFlash::getFlashTimeoutInfo() const\n> +{\n> + return controlInfoMap_->find(V4L2_CID_FLASH_TIMEOUT)->second;\n> +}\n> +\n> +std::optional CameraFlash::getFlashTimeout() const\n> +{\n> + return getSubdevControl(V4L2_CID_FLASH_TIMEOUT);\n> +}\n> +\n> +int CameraFlash::setFlashTimeout(int32_t timeout)\n> +{\n> + return setSubdevControl(V4L2_CID_FLASH_TIMEOUT, timeout);\n> +}\n> +\n> +std::optional CameraFlash::getStrobeSource() const\n> +{\n> + StrobeSource source;\n> +\n> + auto v4l2Source = getSubdevControl(V4L2_CID_FLASH_STROBE_SOURCE);\n> + if (!v4l2Source)\n> + return std::nullopt;\n> +\n> + switch (*v4l2Source) {\n> + case V4L2_FLASH_STROBE_SOURCE_EXTERNAL:\n> + source = StrobeSource::External;\n> + break;\n> + case V4L2_FLASH_STROBE_SOURCE_SOFTWARE:\n> + default:\n> + source = StrobeSource::Software;\n> + break;\n> + }\n> +\n> + return source;\n> +}\n> +\n> +int CameraFlash::setStrobeSource(StrobeSource source)\n> +{\n> + int32_t v4l2Source;\n> +\n> + switch (source) {\n> + case StrobeSource::External:\n> + v4l2Source = V4L2_FLASH_STROBE_SOURCE_EXTERNAL;\n> + break;\n> + case StrobeSource::Software:\n> + v4l2Source = V4L2_FLASH_STROBE_SOURCE_SOFTWARE;\n> + break;\n> + default:\n> + return -EINVAL;\n> + }\n> +\n> + return setSubdevControl(V4L2_CID_FLASH_STROBE_SOURCE, v4l2Source);\n> +}\n> +\n> +int CameraFlash::startStrobe()\n> +{\n> + return setSubdevControl(V4L2_CID_FLASH_STROBE, 1);\n> +}\n> +\n> +int CameraFlash::stopStrobe()\n> +{\n> + return setSubdevControl(V4L2_CID_FLASH_STROBE_STOP, 1);\n> +}\n> +\n> +const ControlInfo &CameraFlash::getTorchIntensityInfo() const\n> +{\n> + return controlInfoMap_->find(V4L2_CID_FLASH_TORCH_INTENSITY)->second;\n> +}\n> +\n> +std::optional CameraFlash::getTorchIntensity() const\n> +{\n> + return getSubdevControl(V4L2_CID_FLASH_TORCH_INTENSITY);\n> +}\n> +\n> +int CameraFlash::setTorchIntensity(int32_t intensity)\n> +{\n> + return setSubdevControl(V4L2_CID_FLASH_TORCH_INTENSITY, intensity);\n> +}\n> +\n> +std::string CameraFlash::logPrefix() const\n> +{\n> + return \"'\" + entity_->name() + \"'\";\n> +}\n> +\n> +std::optional CameraFlash::getSubdevControl(uint32_t id) const\n> +{\n> + ControlList controlList = subdev_->getControls(std::array{ id });\n> +\n> + if (controlList.contains(id))\n> + return std::nullopt;\n> +\n> + return controlList.get(id).get();\n> +}\n> +\n> +int CameraFlash::setSubdevControl(uint32_t id, int32_t value)\n> +{\n> + ControlList flashCtrls(*controlInfoMap_);\n> +\n> + flashCtrls.set(id, value);\n> +\n> + if (subdev_->setControls(&flashCtrls))\n> + return -EINVAL;\n> +\n> + return 0;\n> +}\n> +\n> +int CameraFlash::validateDriver()\n> +{\n> + int ret = 0;\n> + static constexpr uint32_t mandatoryControls[] = {\n> + V4L2_CID_FLASH_LED_MODE,\n> + V4L2_CID_FLASH_STROBE_SOURCE,\n> + V4L2_CID_FLASH_STROBE,\n> + V4L2_CID_FLASH_TIMEOUT,\n> + V4L2_CID_FLASH_INTENSITY,\n> + V4L2_CID_FLASH_TORCH_INTENSITY,\n> + };\n\nThis all looks good to me. The thoughts I have are relating to whether\nSTROBE controls should be mandatory in general; If a torch device only\nserves as a torch, I don't think it should have to implement strobe\ncontrols. When I've used v4l2_flash for torches in the past I have\nimplemented the strobe functionality as a function that just returns 0\nso I can register the v4l2_flash in the first place. But that's a\ndiscussion for the maintainers of v4l2_flash in the kernel.\n\nReviewed-by: Isaac Scott \n\n> +\n> + for (uint32_t ctrl : mandatoryControls) {\n> + if (!controlInfoMap_->count(ctrl)) {\n> + LOG(CameraFlash, Error)\n> + << \"Mandatory V4L2 control \" << utils::hex(ctrl)\n> + << \" not available\";\n> + ret = -EINVAL;\n> + }\n> + }\n> +\n> + if (ret) {\n> + LOG(CameraFlash, Error)\n> + << \"The flash kernel driver needs to be fixed\";\n> + LOG(CameraFlash, Error)\n> + << \"See Documentation/flash_driver_requirements.rst in\"\n> + << \" the libcamera sources for more information\";\n> + return ret;\n> + }\n> +\n> + return ret;\n> +}\n> +\n> +} /* namespace libcamera */\n> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build\n> index b3ca27f217da4ba3a896ef7cbfb5502fa82a4907..0f125661a51e2431c1febc353cef30a1219f9ce7 100644\n> --- a/src/libcamera/meson.build\n> +++ b/src/libcamera/meson.build\n> @@ -20,6 +20,7 @@ libcamera_internal_sources = files([\n> 'bayer_format.cpp',\n> 'byte_stream_buffer.cpp',\n> 'camera_controls.cpp',\n> + 'camera_flash.cpp',\n> 'camera_lens.cpp',\n> 'clock_recovery.cpp',\n> 'control_serializer.cpp',\n> diff --git a/src/libcamera/sensor/camera_sensor_legacy.cpp b/src/libcamera/sensor/camera_sensor_legacy.cpp\n> index f9e685a9acc499fc91d51ed1d66780a0ad2d2a8f..632b66ea0aa15fcd654e7f0efb50c24cb9b973bf 100644\n> --- a/src/libcamera/sensor/camera_sensor_legacy.cpp\n> +++ b/src/libcamera/sensor/camera_sensor_legacy.cpp\n> @@ -31,6 +31,7 @@\n> #include \n> \n> #include \"libcamera/internal/bayer_format.h\"\n> +#include \"libcamera/internal/camera_flash.h\"\n> #include \"libcamera/internal/camera_lens.h\"\n> #include \"libcamera/internal/camera_sensor.h\"\n> #include \"libcamera/internal/camera_sensor_properties.h\"\n> @@ -68,6 +69,7 @@ public:\n> V4L2Subdevice *device() override { return subdev_.get(); }\n> \n> CameraLens *focusLens() override { return focusLens_.get(); }\n> + CameraFlash *flash() override { return flash_.get(); }\n> \n> const std::vector &mbusCodes() const override { return mbusCodes_; }\n> std::vector sizes(unsigned int mbusCode) const override;\n> @@ -139,6 +141,7 @@ private:\n> ControlList properties_;\n> \n> std::unique_ptr focusLens_;\n> + std::unique_ptr flash_;\n> };\n> \n> /**\n> @@ -665,6 +668,16 @@ int CameraSensorLegacy::discoverAncillaryDevices()\n> }\n> break;\n> \n> + case MEDIA_ENT_F_FLASH:\n> + flash_ = std::make_unique(ancillary);\n> + ret = flash_->init();\n> + if (ret) {\n> + LOG(CameraSensor, Error)\n> + << \"Flash initialisation failed, flash disabled\";\n> + flash_.reset();\n> + }\n> + break;\n> +\n> default:\n> LOG(CameraSensor, Warning)\n> << \"Unsupported ancillary entity function \"\n> diff --git a/src/libcamera/sensor/camera_sensor_raw.cpp b/src/libcamera/sensor/camera_sensor_raw.cpp\n> index 8ea4423698cd8c1eaae43eb5ba8b5d524b94d515..9d533d814b9df453aa4009a87818c1558bcbd665 100644\n> --- a/src/libcamera/sensor/camera_sensor_raw.cpp\n> +++ b/src/libcamera/sensor/camera_sensor_raw.cpp\n> @@ -32,6 +32,7 @@\n> #include \n> \n> #include \"libcamera/internal/bayer_format.h\"\n> +#include \"libcamera/internal/camera_flash.h\"\n> #include \"libcamera/internal/camera_lens.h\"\n> #include \"libcamera/internal/camera_sensor.h\"\n> #include \"libcamera/internal/camera_sensor_properties.h\"\n> @@ -69,6 +70,7 @@ public:\n> V4L2Subdevice *device() override { return subdev_.get(); }\n> \n> CameraLens *focusLens() override { return focusLens_.get(); }\n> + CameraFlash *flash() override { return flash_.get(); }\n> \n> const std::vector &mbusCodes() const override { return mbusCodes_; }\n> std::vector sizes(unsigned int mbusCode) const override;\n> @@ -150,6 +152,7 @@ private:\n> ControlList properties_;\n> \n> std::unique_ptr focusLens_;\n> + std::unique_ptr flash_;\n> };\n> \n> /**\n> @@ -513,6 +516,16 @@ std::optional CameraSensorRaw::init()\n> }\n> break;\n> \n> + case MEDIA_ENT_F_FLASH:\n> + flash_ = std::make_unique(ancillary);\n> + ret = flash_->init();\n> + if (ret) {\n> + LOG(CameraSensor, Error)\n> + << \"Flash initialisation failed, flash disabled\";\n> + flash_.reset();\n> + }\n> + break;\n> +\n> default:\n> LOG(CameraSensor, Warning)\n> << \"Unsupported ancillary entity function \"\n> \n> -- \n> 2.34.1\n> \n\nBest wishes,\n\nIsaac","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 7EF63C328C\n\tfor ;\n\tTue, 16 Sep 2025 11:06:04 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 43AE66936F;\n\tTue, 16 Sep 2025 13:06:03 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id A236B613A1\n\tfor ;\n\tTue, 16 Sep 2025 13:06:01 +0200 (CEST)","from thinkpad.ideasonboard.com\n\t(cpc89244-aztw30-2-0-cust6594.18-1.cable.virginm.net [86.31.185.195])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 63C8FDF3;\n\tTue, 16 Sep 2025 13:04:43 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; 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