* [PATCH v5 1/1] media: v4l2-common: Add helper function media_bus_fmt_to_csi2_(bpp|dt)()
@ 2026-05-14 18:33 Frank Li
2026-05-14 21:10 ` sashiko-bot
0 siblings, 1 reply; 2+ messages in thread
From: Frank Li @ 2026-05-14 18:33 UTC (permalink / raw)
To: Mauro Carvalho Chehab, Hans Verkuil, Laurent Pinchart,
Sakari Ailus, Mehdi Djait, Niklas Söderlund, Daniel Scally,
Nas Chung, Frank Li, Isaac Scott, Paul Cercueil,
open list:MEDIA INPUT INFRASTRUCTURE (V4L/DVB), open list
Cc: imx
Add helper function media_bus_fmt_to_csi2_bpp() to get media bus fmt's bpp
to reduce codes such as
static const struct imx7_csi_pixfmt pixel_formats[] = {
{
.fourcc = V4L2_PIX_FMT_UYVY,
.codes = IMX_BUS_FMTS(
MEDIA_BUS_FMT_UYVY8_2X8,
MEDIA_BUS_FMT_UYVY8_1X16
),
.yuv = true,
.bpp = 16,
},
....
.bpp can be removed from pixel_formats with this helper function.
CSI2 data type is defined by MIPI Camera Serial Interface 2 Spec Ver4.1.
See section 9.4.
Add helper function media_bus_fmt_to_csi2_dt() to convert media bus fmt to
MIPI defined data type and avoid below duplicated static array in each CSI2
drivers.
{
.code = MEDIA_BUS_FMT_UYVY8_1X16,
.data_type = MIPI_CSI2_DT_YUV422_8B,
}
Only add known map for dt type. Need update media_bus_fmt_info when new
mapping used.
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
change in v5
- use u32 for bus_fmt and include type.h
- fix MEDIA_BUS_FMT_AHSV8888_1X32 bpp value from 8 to 32 (sashiko AI)
- change return type to int for media_bus_fmt_to_csi2_bpp
- check bpp value to indicate dt exist because dt code 0 is valid value (sashiko AI)
- change macro to MIPI_CSI2_DT_INVALID
Change in v4
- add space after }
- fix bpps value when m_nXk (m.n*k)
- add comments about bpp defination. only convert from suffix of
MEDIA_BUS_FMT_*
- move struct media_bus_fmt_info to c file
- change field name fmt to code
There are some open at
https://lore.kernel.org/linux-media/20251013-csi-bgr-rgb-v4-0-55eab2caa69f@kernel.org/.
this version just fix known review comments.
Change in v3:
- squash two help function patch to one.
- use media_bus_fmt_info to do map.
---
drivers/media/v4l2-core/v4l2-common.c | 183 ++++++++++++++++++++++++++
include/media/mipi-csi2.h | 27 ++++
2 files changed, 210 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
index bceafc4e92c81..6c8afb96e60fe 100644
--- a/drivers/media/v4l2-core/v4l2-common.c
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -46,6 +46,7 @@
#include <linux/uaccess.h>
#include <asm/io.h>
#include <asm/div64.h>
+#include <media/mipi-csi2.h>
#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ctrls.h>
@@ -808,3 +809,185 @@ struct clk *__devm_v4l2_sensor_clk_get(struct device *dev, const char *id,
return clk_hw->clk;
}
EXPORT_SYMBOL_GPL(__devm_v4l2_sensor_clk_get);
+
+/**
+ * struct media_bus_fmt_info - information about a media bus format
+ * @code: media bus format identifier (MEDIA_BUS_FMT_*)
+ * @dt: data type define in MIPI spec (MIPI_CSI2_DT *)
+ * @bpp: bit width per pixel, which is suffix from MEDIA_BUS_FMT_*, no pad. no
+ * compressed data.
+ */
+struct media_bus_fmt_info {
+ u32 code;
+ u8 dt;
+ u8 bpp;
+};
+
+static const struct media_bus_fmt_info media_bus_fmt_info[] = {
+ { .code = MEDIA_BUS_FMT_RGB444_1X12, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_RGB444_2X8_PADHI_LE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_RGB555_2X8_PADHI_BE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_RGB555_2X8_PADHI_LE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_RGB565_1X16, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_BGR565_2X8_BE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_BGR565_2X8_LE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_RGB565_2X8_BE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_RGB565_2X8_LE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_RGB666_1X18, .bpp = 18 },
+ { .code = MEDIA_BUS_FMT_RGB666_2X9_BE, .bpp = 18 },
+ { .code = MEDIA_BUS_FMT_BGR666_1X18, .bpp = 18 },
+ { .code = MEDIA_BUS_FMT_RBG888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB666_1X24_CPADHI, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_BGR666_1X24_CPADHI, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB565_1X24_CPADHI, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB666_1X7X3_SPWG, .bpp = 21 },
+ { .code = MEDIA_BUS_FMT_BGR888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_BGR888_3X8, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_GBR888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB888_2X12_BE, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB888_2X12_LE, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB888_3X8, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB888_3X8_DELTA, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_RGB888_1X7X4_SPWG, .bpp = 28 },
+ { .code = MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA, .bpp = 28 },
+ { .code = MEDIA_BUS_FMT_RGB666_1X30_CPADLO, .bpp = 30 },
+ { .code = MEDIA_BUS_FMT_RGB888_1X30_CPADLO, .bpp = 30 },
+ { .code = MEDIA_BUS_FMT_ARGB8888_1X32, .bpp = 32 },
+ { .code = MEDIA_BUS_FMT_RGB888_1X32_PADHI, .bpp = 32 },
+ { .code = MEDIA_BUS_FMT_RGB101010_1X30, .bpp = 30 },
+ { .code = MEDIA_BUS_FMT_RGB101010_1X7X5_SPWG, .bpp = 35 },
+ { .code = MEDIA_BUS_FMT_RGB101010_1X7X5_JEIDA, .bpp = 35 },
+ { .code = MEDIA_BUS_FMT_RGB666_1X36_CPADLO, .bpp = 36 },
+ { .code = MEDIA_BUS_FMT_RGB888_1X36_CPADLO, .bpp = 36 },
+ { .code = MEDIA_BUS_FMT_RGB121212_1X36, .bpp = 36 },
+ { .code = MEDIA_BUS_FMT_RGB161616_1X48, .bpp = 48 },
+
+ { .code = MEDIA_BUS_FMT_Y8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_UV8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_UYVY8_1_5X8, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_VYUY8_1_5X8, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_YUYV8_1_5X8, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_YVYU8_1_5X8, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_UYVY8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_VYUY8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_YUYV8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_YVYU8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_Y10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10 },
+ { .code = MEDIA_BUS_FMT_Y10_2X8_PADHI_LE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_UYVY10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_VYUY10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_YUYV10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_YVYU10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_Y12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_UYVY12_2X12, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_VYUY12_2X12, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_YUYV12_2X12, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_YVYU12_2X12, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_Y14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14 },
+ { .code = MEDIA_BUS_FMT_Y16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_UYVY8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_VYUY8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_YUYV8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_YVYU8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_YDYUYDYV8_1X16, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_UYVY10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_VYUY10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_YUYV10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_YVYU10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_VUY8_1X24, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_YUV8_1X24, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_UYYVYY8_0_5X24, .dt = MIPI_CSI2_DT_YUV420_8B, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_UYVY12_1X24, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_VYUY12_1X24, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_YUYV12_1X24, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_YVYU12_1X24, .bpp = 24 },
+ { .code = MEDIA_BUS_FMT_YUV10_1X30, .bpp = 30 },
+ { .code = MEDIA_BUS_FMT_UYYVYY10_0_5X30, .bpp = 15 },
+ { .code = MEDIA_BUS_FMT_AYUV8_1X32, .bpp = 32 },
+ { .code = MEDIA_BUS_FMT_UYYVYY12_0_5X36, .bpp = 18 },
+ { .code = MEDIA_BUS_FMT_YUV12_1X36, .bpp = 36 },
+ { .code = MEDIA_BUS_FMT_YUV16_1X48, .bpp = 48 },
+ { .code = MEDIA_BUS_FMT_UYYVYY16_0_5X48, .bpp = 24 },
+
+ { .code = MEDIA_BUS_FMT_SBGGR8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SGBRG8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SGRBG8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SRGGB8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SBGGR10_ALAW8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SGBRG10_ALAW8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SGRBG10_ALAW8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SRGGB10_ALAW8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SBGGR10_DPCM8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SGBRG10_DPCM8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SRGGB10_DPCM8_1X8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_SBGGR10_2X8_PADHI_BE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_SBGGR10_2X8_PADHI_LE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_SBGGR10_2X8_PADLO_BE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_SBGGR10_2X8_PADLO_LE, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_SBGGR10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10 },
+ { .code = MEDIA_BUS_FMT_SGBRG10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10 },
+ { .code = MEDIA_BUS_FMT_SGRBG10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10 },
+ { .code = MEDIA_BUS_FMT_SRGGB10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10 },
+ { .code = MEDIA_BUS_FMT_SBGGR12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_SGBRG12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_SGRBG12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_SRGGB12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_SBGGR14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14 },
+ { .code = MEDIA_BUS_FMT_SGBRG14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14 },
+ { .code = MEDIA_BUS_FMT_SGRBG14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14 },
+ { .code = MEDIA_BUS_FMT_SRGGB14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14 },
+ { .code = MEDIA_BUS_FMT_SBGGR16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_SGBRG16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_SGRBG16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_SRGGB16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16 },
+
+ { .code = MEDIA_BUS_FMT_JPEG_1X8, .bpp = 8 },
+
+ { .code = MEDIA_BUS_FMT_S5C_UYVY_JPEG_1X8, .bpp = 8 },
+
+ { .code = MEDIA_BUS_FMT_AHSV8888_1X32, .bpp = 32 },
+
+ { .code = MEDIA_BUS_FMT_META_8, .bpp = 8 },
+ { .code = MEDIA_BUS_FMT_META_10, .bpp = 10 },
+ { .code = MEDIA_BUS_FMT_META_12, .bpp = 12 },
+ { .code = MEDIA_BUS_FMT_META_14, .bpp = 14 },
+ { .code = MEDIA_BUS_FMT_META_16, .bpp = 16 },
+ { .code = MEDIA_BUS_FMT_META_20, .bpp = 20 },
+ { .code = MEDIA_BUS_FMT_META_24, .bpp = 24 },
+};
+
+static const struct media_bus_fmt_info *media_bus_fmt_info_get(u32 bus_fmt)
+{
+ for (unsigned int i = 0; i < ARRAY_SIZE(media_bus_fmt_info); i++) {
+ if (media_bus_fmt_info[i].code == bus_fmt)
+ return &media_bus_fmt_info[i];
+ }
+
+ return NULL;
+}
+
+u32 media_bus_fmt_to_csi2_dt(u32 bus_fmt)
+{
+ const struct media_bus_fmt_info *info = media_bus_fmt_info_get(bus_fmt);
+
+ if (!info)
+ return MIPI_CSI2_DT_INVALID;
+
+ /* Check bpp because 0 (MIPI_CSI2_DT_FS) is a valid data type code */
+ return info->bpp ? info->dt : MIPI_CSI2_DT_INVALID;
+}
+EXPORT_SYMBOL_GPL(media_bus_fmt_to_csi2_dt);
+
+int media_bus_fmt_to_csi2_bpp(u32 bus_fmt)
+{
+ const struct media_bus_fmt_info *info = media_bus_fmt_info_get(bus_fmt);
+
+ if (!info)
+ return -EINVAL;
+
+ return info->bpp ? info->bpp : -EINVAL;
+}
+EXPORT_SYMBOL_GPL(media_bus_fmt_to_csi2_bpp);
diff --git a/include/media/mipi-csi2.h b/include/media/mipi-csi2.h
index 40fc0264250d7..bb5054f0cf310 100644
--- a/include/media/mipi-csi2.h
+++ b/include/media/mipi-csi2.h
@@ -8,6 +8,8 @@
#ifndef _MEDIA_MIPI_CSI2_H
#define _MEDIA_MIPI_CSI2_H
+#include <linux/types.h>
+
/* Short packet data types */
#define MIPI_CSI2_DT_FS 0x00
#define MIPI_CSI2_DT_FE 0x01
@@ -44,4 +46,29 @@
#define MIPI_CSI2_DT_RAW20 0x2f
#define MIPI_CSI2_DT_USER_DEFINED(n) (0x30 + (n)) /* 0..7 */
+/* Use one undefined value in spec */
+#define MIPI_CSI2_DT_INVALID 0xff
+
+/**
+ * media_bus_fmt_to_csi2_dt - Get MIPI CSI2 data type from media bus format
+ *
+ * @bus_fmt: media bus format identifier (MEDIA_BUS_FMT_*)
+ *
+ * Return: MIPI CSI2 data type MIPI_CSI2_DT_*, MIPI_CSI2_DT_INVALIDATE means
+ * can't get data type from bus_fmt.
+ */
+u32 media_bus_fmt_to_csi2_dt(u32 bus_fmt);
+
+/**
+ * media_bus_fmt_to_csi2_bpp - Get media bus format's bit depth
+ *
+ * @bus_fmt: media bus format identifier (MEDIA_BUS_FMT_*)
+ *
+ * Return: bit depth, -EINVAL if fail to get from bus_fmt.
+ *
+ * Notes: this bpp is suffix from MEDIA_BUS_FMT_*, no pad, not for compressed
+ * data.
+ */
+int media_bus_fmt_to_csi2_bpp(u32 bus_fmt);
+
#endif /* _MEDIA_MIPI_CSI2_H */
--
2.43.0
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH v5 1/1] media: v4l2-common: Add helper function media_bus_fmt_to_csi2_(bpp|dt)()
2026-05-14 18:33 [PATCH v5 1/1] media: v4l2-common: Add helper function media_bus_fmt_to_csi2_(bpp|dt)() Frank Li
@ 2026-05-14 21:10 ` sashiko-bot
0 siblings, 0 replies; 2+ messages in thread
From: sashiko-bot @ 2026-05-14 21:10 UTC (permalink / raw)
To: Frank Li; +Cc: imx, Frank.Li
Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] media_bus_fmt_to_csi2_dt() incorrectly returns 0 (MIPI_CSI2_DT_FS) instead of MIPI_CSI2_DT_INVALID for formats without a mapped CSI-2 data type.
- [Low] Mismatch between kernel-doc comment and macro definition for the invalid data type indicator.
--
commit dd2f0971f75dadcf691d8ed964c49386a1fc2170
Author: Frank Li <Frank.Li@nxp.com>
media: v4l2-common: Add helper function media_bus_fmt_to_csi2_(bpp|dt)()
This commit adds helper functions media_bus_fmt_to_csi2_bpp() and
media_bus_fmt_to_csi2_dt() to convert media bus formats to MIPI CSI-2 bit
depths and data types. This aims to reduce duplicate static mapping arrays
across different CSI-2 drivers.
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index bceafc4e92c81..6c8afb96e60fe 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
[ ... ]
> +static const struct media_bus_fmt_info media_bus_fmt_info[] = {
> + { .code = MEDIA_BUS_FMT_RGB444_1X12, .bpp = 12 },
> + { .code = MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE, .bpp = 16 },
[ ... ]
> +u32 media_bus_fmt_to_csi2_dt(u32 bus_fmt)
> +{
> + const struct media_bus_fmt_info *info = media_bus_fmt_info_get(bus_fmt);
> +
> + if (!info)
> + return MIPI_CSI2_DT_INVALID;
> +
> + /* Check bpp because 0 (MIPI_CSI2_DT_FS) is a valid data type code */
> + return info->bpp ? info->dt : MIPI_CSI2_DT_INVALID;
> +}
Since uninitialized fields in a struct array are zero-initialized in C, any
entry in media_bus_fmt_info without an explicit .dt value will have .dt = 0.
Because every entry in the array defines a non-zero .bpp, info->bpp is always
true for matched formats. Doesn't this mean the function will return 0 for
unmapped formats rather than MIPI_CSI2_DT_INVALID?
If 0 is returned, this maps to MIPI_CSI2_DT_FS (Frame Start). Could this
cause drivers to silently program the camera hardware with a short-packet
Frame Start data type for pixel data instead of rejecting the unsupported
format?
> diff --git a/include/media/mipi-csi2.h b/include/media/mipi-csi2.h
> index 40fc0264250d7..bb5054f0cf310 100644
> --- a/include/media/mipi-csi2.h
> +++ b/include/media/mipi-csi2.h
[ ... ]
> +/* Use one undefined value in spec */
> +#define MIPI_CSI2_DT_INVALID 0xff
> +
> +/**
> + * media_bus_fmt_to_csi2_dt - Get MIPI CSI2 data type from media bus format
> + *
> + * @bus_fmt: media bus format identifier (MEDIA_BUS_FMT_*)
> + *
> + * Return: MIPI CSI2 data type MIPI_CSI2_DT_*, MIPI_CSI2_DT_INVALIDATE means
> + * can't get data type from bus_fmt.
> + */
This isn't a bug, but there is a typo in the documentation. The macro defined
above is MIPI_CSI2_DT_INVALID, but the kernel-doc references
MIPI_CSI2_DT_INVALIDATE.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260514183357.3088564-1-Frank.Li@nxp.com?part=1
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2026-05-14 18:33 [PATCH v5 1/1] media: v4l2-common: Add helper function media_bus_fmt_to_csi2_(bpp|dt)() Frank Li
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