[libcamera-devel] [PATCH v3 08/13] libcamera: v4l2_subdevice: Add format information

[Jacopo Mondi]

Define a map of static information associated with a media bus code.
Start by reporting the bits-per-pixel for each media bus code defined by
the V4L2 kernel API, to later expand it when necessary.

Add to the V4L2SubdeviceFormat class a method to return the bits per
pixel, retrieved by inspecting the static map of format information.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/include/v4l2_subdevice.h |   3 +
 src/libcamera/v4l2_subdevice.cpp       | 113 +++++++++++++++++++++++++
 2 files changed, 116 insertions(+)

diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
index 763ffadb61fb..43953a0a5a6c 100644
--- a/src/libcamera/include/v4l2_subdevice.h
+++ b/src/libcamera/include/v4l2_subdevice.h
@@ -23,10 +23,13 @@ namespace libcamera {
 class MediaDevice;
 
 struct V4L2SubdeviceFormat {
+	using infoMap = std::map<uint32_t, uint8_t>;
+
 	uint32_t mbus_code;
 	Size size;
 
 	const std::string toString() const;
+	uint8_t bitsPerPixel() const;
 };
 
 class V4L2Subdevice : public V4L2Device
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index 4dcf8ce48754..6f72c363fc7f 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -14,6 +14,7 @@
 #include <sys/ioctl.h>
 #include <unistd.h>
 
+#include <linux/media-bus-format.h>
 #include <linux/v4l2-subdev.h>
 
 #include <libcamera/geometry.h>
@@ -32,6 +33,92 @@ namespace libcamera {
 
 LOG_DECLARE_CATEGORY(V4L2)
 
+namespace {
+
+/*
+ * \var formatInfoMap
+ * \brief A map that associates information to V4L2 media bus codes
+ */
+const V4L2SubdeviceFormat::infoMap formatInfoMap = {
+	{ V4L2_MBUS_FMT_RGB444_2X8_PADHI_BE, 16 },
+	{ V4L2_MBUS_FMT_RGB444_2X8_PADHI_LE, 16 },
+	{ V4L2_MBUS_FMT_RGB555_2X8_PADHI_BE, 16 },
+	{ V4L2_MBUS_FMT_RGB555_2X8_PADHI_LE, 16 },
+	{ V4L2_MBUS_FMT_BGR565_2X8_BE, 16 },
+	{ V4L2_MBUS_FMT_BGR565_2X8_LE, 16 },
+	{ V4L2_MBUS_FMT_RGB565_2X8_BE, 16 },
+	{ V4L2_MBUS_FMT_RGB565_2X8_LE, 16 },
+	{ V4L2_MBUS_FMT_RGB666_1X18, 18 },
+	{ V4L2_MBUS_FMT_RGB888_1X24, 24 },
+	{ V4L2_MBUS_FMT_RGB888_2X12_BE, 24 },
+	{ V4L2_MBUS_FMT_RGB888_2X12_LE, 24 },
+	{ V4L2_MBUS_FMT_ARGB8888_1X32, 32 },
+	{ V4L2_MBUS_FMT_Y8_1X8, 8 },
+	{ V4L2_MBUS_FMT_UV8_1X8, 8 },
+	{ V4L2_MBUS_FMT_UYVY8_1_5X8, 40 },
+	{ V4L2_MBUS_FMT_VYUY8_1_5X8, 40 },
+	{ V4L2_MBUS_FMT_YUYV8_1_5X8, 40 },
+	{ V4L2_MBUS_FMT_YVYU8_1_5X8, 40 },
+	{ V4L2_MBUS_FMT_UYVY8_2X8, 16 },
+	{ V4L2_MBUS_FMT_VYUY8_2X8, 16 },
+	{ V4L2_MBUS_FMT_YUYV8_2X8, 16 },
+	{ V4L2_MBUS_FMT_YVYU8_2X8, 16 },
+	{ V4L2_MBUS_FMT_Y10_1X10, 10 },
+	{ V4L2_MBUS_FMT_UYVY10_2X10, 20 },
+	{ V4L2_MBUS_FMT_VYUY10_2X10, 20 },
+	{ V4L2_MBUS_FMT_YUYV10_2X10, 20 },
+	{ V4L2_MBUS_FMT_YVYU10_2X10, 20 },
+	{ V4L2_MBUS_FMT_Y12_1X12, 12 },
+	{ V4L2_MBUS_FMT_UYVY8_1X16, 16 },
+	{ V4L2_MBUS_FMT_VYUY8_1X16, 16 },
+	{ V4L2_MBUS_FMT_YUYV8_1X16, 16 },
+	{ V4L2_MBUS_FMT_YVYU8_1X16, 16 },
+	{ V4L2_MBUS_FMT_YDYUYDYV8_1X16, 16 },
+	{ V4L2_MBUS_FMT_UYVY10_1X20, 20 },
+	{ V4L2_MBUS_FMT_VYUY10_1X20, 20 },
+	{ V4L2_MBUS_FMT_YUYV10_1X20, 20 },
+	{ V4L2_MBUS_FMT_YVYU10_1X20, 20 },
+	{ V4L2_MBUS_FMT_YUV10_1X30, 30 },
+	{ V4L2_MBUS_FMT_AYUV8_1X32, 32 },
+	{ V4L2_MBUS_FMT_UYVY12_2X12, 24 },
+	{ V4L2_MBUS_FMT_VYUY12_2X12, 24 },
+	{ V4L2_MBUS_FMT_YUYV12_2X12, 24 },
+	{ V4L2_MBUS_FMT_YVYU12_2X12, 24 },
+	{ V4L2_MBUS_FMT_UYVY12_1X24, 24 },
+	{ V4L2_MBUS_FMT_VYUY12_1X24, 24 },
+	{ V4L2_MBUS_FMT_YUYV12_1X24, 24 },
+	{ V4L2_MBUS_FMT_YVYU12_1X24, 24 },
+	{ V4L2_MBUS_FMT_SBGGR8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SGBRG8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SGRBG8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SRGGB8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SBGGR10_ALAW8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SGBRG10_ALAW8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SGRBG10_ALAW8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SRGGB10_ALAW8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SBGGR10_DPCM8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SGBRG10_DPCM8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SGRBG10_DPCM8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SRGGB10_DPCM8_1X8, 8 },
+	{ V4L2_MBUS_FMT_SBGGR10_2X8_PADHI_BE, 16 },
+	{ V4L2_MBUS_FMT_SBGGR10_2X8_PADHI_LE, 16 },
+	{ V4L2_MBUS_FMT_SBGGR10_2X8_PADLO_BE, 16 },
+	{ V4L2_MBUS_FMT_SBGGR10_2X8_PADLO_LE, 16 },
+	{ V4L2_MBUS_FMT_SBGGR10_1X10, 10 },
+	{ V4L2_MBUS_FMT_SGBRG10_1X10, 10 },
+	{ V4L2_MBUS_FMT_SGRBG10_1X10, 10 },
+	{ V4L2_MBUS_FMT_SRGGB10_1X10, 10 },
+	{ V4L2_MBUS_FMT_SBGGR12_1X12, 24 },
+	{ V4L2_MBUS_FMT_SGBRG12_1X12, 24 },
+	{ V4L2_MBUS_FMT_SGRBG12_1X12, 24 },
+	{ V4L2_MBUS_FMT_SRGGB12_1X12, 24 },
+	{ V4L2_MBUS_FMT_JPEG_1X8, 8 },
+	{ V4L2_MBUS_FMT_S5C_UYVY_JPEG_1X8, 8 },
+	{ V4L2_MBUS_FMT_AHSV8888_1X32, 32 },
+};
+
+}; /* namespace */
+
 /**
  * \struct V4L2SubdeviceFormat
  * \brief The V4L2 sub-device image format and sizes
@@ -60,6 +147,14 @@ LOG_DECLARE_CATEGORY(V4L2)
  * Section 4.15.3.1 of the above mentioned Linux kernel documentation section.
  */
 
+/**
+ * \typedef V4L2SubdeviceFormat::infoMap
+ * \brief Map of static information associated with a V4L2 subdevice format
+ *
+ * \todo Expand with additional information. At the moment only the
+ * bits-per-pixel information is reported.
+ */
+
 /**
  * \var V4L2SubdeviceFormat::mbus_code
  * \brief The image format bus code
@@ -81,6 +176,24 @@ const std::string V4L2SubdeviceFormat::toString() const
 	return ss.str();
 }
 
+/**
+ * \brief Retrieve the number of bits per pixel for the V4L2 subdevice format
+ * \return The number of bits per pixel for the format, or default it to 8 if
+ * the format's mbus code is not supported
+ */
+uint8_t V4L2SubdeviceFormat::bitsPerPixel() const
+{
+	const auto it = formatInfoMap.find(mbus_code);
+	if (it == formatInfoMap.end()) {
+		LOG(V4L2, Error) << "No information available for format: '"
+				 << toString() << "'";
+		/* Return 8 to avoid divisions by 0. */
+		return 8;
+	}
+
+	return it->second;
+}
+
 /**
  * \class V4L2Subdevice
  * \brief A V4L2 subdevice as exposed by the Linux kernel
-- 
2.26.1