Re: [PATCH v3 03/31] media: v4l2-common: Add helper function media_bus_fmt_to_csi2_(bpp|dt)()

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Frank,

Thank you for the patch.

On Thu, Aug 21, 2025 at 04:15:38PM -0400, Frank Li wrote:
> 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 v3:
> - squash two help function patch to one.
> - use media_bus_fmt_info to do map.
> ---
>  drivers/media/v4l2-core/v4l2-common.c | 149 ++++++++++++++++++++++++++++++++++
>  include/media/mipi-csi2.h             |  30 +++++++
>  2 files changed, 179 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index a5334aa35992e5f57fb228c33d40c51fdafdc135..a75987aa5fc69d6368709b7d521bede666da9513 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>
> @@ -757,3 +758,151 @@ 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);
> +
> +static const struct media_bus_fmt_info media_bus_fmt_info[] = {
> +	{ .fmt = MEDIA_BUS_FMT_RGB444_1X12, .bpp = 12},

Missing space before }.

> +	{ .fmt = MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_RGB444_2X8_PADHI_LE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_RGB555_2X8_PADHI_BE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_RGB555_2X8_PADHI_LE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_RGB565_1X16, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_BGR565_2X8_BE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16},

Let's not specify .dt for formats that must not be used with CSI-2
buses.

> +	{ .fmt = MEDIA_BUS_FMT_BGR565_2X8_LE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_RGB565_2X8_BE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_RGB565_2X8_LE, .dt = MIPI_CSI2_DT_RGB565, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_RGB666_1X18, .bpp = 18},
> +	{ .fmt = MEDIA_BUS_FMT_RGB666_2X9_BE, .bpp = 18},
> +	{ .fmt = MEDIA_BUS_FMT_BGR666_1X18, .bpp = 18},
> +	{ .fmt = MEDIA_BUS_FMT_RBG888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB666_1X24_CPADHI, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_BGR666_1X24_CPADHI, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB565_1X24_CPADHI, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB666_1X7X3_SPWG, .bpp = 21},
> +	{ .fmt = MEDIA_BUS_FMT_BGR888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_BGR888_3X8, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_GBR888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_1X24, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_2X12_BE, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_2X12_LE, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_3X8, .dt = MIPI_CSI2_DT_RGB888, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_3X8_DELTA, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_1X7X4_SPWG, .bpp = 28},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA, .bpp = 28},
> +	{ .fmt = MEDIA_BUS_FMT_RGB666_1X30_CPADLO, .bpp = 30},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_1X30_CPADLO, .bpp = 30},
> +	{ .fmt = MEDIA_BUS_FMT_ARGB8888_1X32, .bpp = 32},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_1X32_PADHI, .bpp = 32},
> +	{ .fmt = MEDIA_BUS_FMT_RGB101010_1X30, .bpp = 30},
> +	{ .fmt = MEDIA_BUS_FMT_RGB101010_1X7X5_SPWG, .bpp = 35},
> +	{ .fmt = MEDIA_BUS_FMT_RGB101010_1X7X5_JEIDA, .bpp = 35},
> +	{ .fmt = MEDIA_BUS_FMT_RGB666_1X36_CPADLO, .bpp = 36},
> +	{ .fmt = MEDIA_BUS_FMT_RGB888_1X36_CPADLO, .bpp = 36},
> +	{ .fmt = MEDIA_BUS_FMT_RGB121212_1X36, .bpp = 36},
> +	{ .fmt = MEDIA_BUS_FMT_RGB161616_1X48, .bpp = 48},
> +
> +	{ .fmt = MEDIA_BUS_FMT_Y8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_UV8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_UYVY8_1_5X8, .bpp = 40},

This doesn't seem correct.

> +	{ .fmt = MEDIA_BUS_FMT_VYUY8_1_5X8, .bpp = 40},
> +	{ .fmt = MEDIA_BUS_FMT_YUYV8_1_5X8, .bpp = 40},
> +	{ .fmt = MEDIA_BUS_FMT_YVYU8_1_5X8, .bpp = 40},
> +	{ .fmt = MEDIA_BUS_FMT_UYVY8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_VYUY8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_YUYV8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_YVYU8_2X8, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_Y10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10},
> +	{ .fmt = MEDIA_BUS_FMT_Y10_2X8_PADHI_LE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_UYVY10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_VYUY10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_YUYV10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_YVYU10_2X10, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_Y12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12},
> +	{ .fmt = MEDIA_BUS_FMT_UYVY12_2X12, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_VYUY12_2X12, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_YUYV12_2X12, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_YVYU12_2X12, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_Y14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14},
> +	{ .fmt = MEDIA_BUS_FMT_Y16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_UYVY8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_VYUY8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_YUYV8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_YVYU8_1X16, .dt = MIPI_CSI2_DT_YUV422_8B, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_YDYUYDYV8_1X16, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_UYVY10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_VYUY10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_YUYV10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_YVYU10_1X20, .dt = MIPI_CSI2_DT_YUV422_10B, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_VUY8_1X24, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_YUV8_1X24, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_UYYVYY8_0_5X24, .dt = MIPI_CSI2_DT_YUV420_8B, .bpp = 120},
> +	{ .fmt = MEDIA_BUS_FMT_UYVY12_1X24, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_VYUY12_1X24, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_YUYV12_1X24, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_YVYU12_1X24, .bpp = 24},
> +	{ .fmt = MEDIA_BUS_FMT_YUV10_1X30, .bpp = 30},
> +	{ .fmt = MEDIA_BUS_FMT_UYYVYY10_0_5X30, .bpp = 150},
> +	{ .fmt = MEDIA_BUS_FMT_AYUV8_1X32, .bpp = 32},
> +	{ .fmt = MEDIA_BUS_FMT_UYYVYY12_0_5X36, .bpp = 180},
> +	{ .fmt = MEDIA_BUS_FMT_YUV12_1X36, .bpp = 36},
> +	{ .fmt = MEDIA_BUS_FMT_YUV16_1X48, .bpp = 48},
> +	{ .fmt = MEDIA_BUS_FMT_UYYVYY16_0_5X48, .bpp = 240},
> +
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SGBRG8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SGRBG8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SRGGB8_1X8, .dt = MIPI_CSI2_DT_RAW8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR10_ALAW8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SGBRG10_ALAW8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SGRBG10_ALAW8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SRGGB10_ALAW8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR10_DPCM8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SGBRG10_DPCM8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SRGGB10_DPCM8_1X8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR10_2X8_PADHI_BE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR10_2X8_PADHI_LE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR10_2X8_PADLO_BE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR10_2X8_PADLO_LE, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10},
> +	{ .fmt = MEDIA_BUS_FMT_SGBRG10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10},
> +	{ .fmt = MEDIA_BUS_FMT_SGRBG10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10},
> +	{ .fmt = MEDIA_BUS_FMT_SRGGB10_1X10, .dt = MIPI_CSI2_DT_RAW10, .bpp = 10},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12},
> +	{ .fmt = MEDIA_BUS_FMT_SGBRG12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12},
> +	{ .fmt = MEDIA_BUS_FMT_SGRBG12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12},
> +	{ .fmt = MEDIA_BUS_FMT_SRGGB12_1X12, .dt = MIPI_CSI2_DT_RAW12, .bpp = 12},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14},
> +	{ .fmt = MEDIA_BUS_FMT_SGBRG14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14},
> +	{ .fmt = MEDIA_BUS_FMT_SGRBG14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14},
> +	{ .fmt = MEDIA_BUS_FMT_SRGGB14_1X14, .dt = MIPI_CSI2_DT_RAW14, .bpp = 14},
> +	{ .fmt = MEDIA_BUS_FMT_SBGGR16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_SGBRG16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_SGRBG16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_SRGGB16_1X16, .dt = MIPI_CSI2_DT_RAW16, .bpp = 16},
> +
> +	{ .fmt = MEDIA_BUS_FMT_JPEG_1X8, .bpp = 8},
> +
> +	{ .fmt = MEDIA_BUS_FMT_S5C_UYVY_JPEG_1X8, .bpp = 8},
> +
> +	{ .fmt = MEDIA_BUS_FMT_AHSV8888_1X32, .bpp = 8},
> +
> +	{ .fmt = MEDIA_BUS_FMT_META_8, .bpp = 8},
> +	{ .fmt = MEDIA_BUS_FMT_META_10, .bpp = 10},
> +	{ .fmt = MEDIA_BUS_FMT_META_12, .bpp = 12},
> +	{ .fmt = MEDIA_BUS_FMT_META_14, .bpp = 14},
> +	{ .fmt = MEDIA_BUS_FMT_META_16, .bpp = 16},
> +	{ .fmt = MEDIA_BUS_FMT_META_20, .bpp = 20},
> +	{ .fmt = MEDIA_BUS_FMT_META_24, .bpp = 24},
> +};
> +
> +const struct media_bus_fmt_info *media_bus_fmt_info_get(u32 bus_fmt)
> +{
> +	int i;

unsigned

> +
> +	for (i = 0; i < ARRAY_SIZE(media_bus_fmt_info); i++)
> +		if (media_bus_fmt_info[i].fmt == bus_fmt)
> +			return &media_bus_fmt_info[i];

Add curly braces for the "for" statement.

> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(media_bus_fmt_info_get);
> diff --git a/include/media/mipi-csi2.h b/include/media/mipi-csi2.h
> index 40fc0264250d779ab5dfa7d2fe16e6f1382c07d4..3227d28224b7c32ef2745548391da9e792cfa559 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
>  
> +/* DT value ref to MIPI Camera Serial Interface 2 Spec Ver4.1 section 9.4 */
> +
>  /* Short packet data types */
>  #define MIPI_CSI2_DT_FS			0x00
>  #define MIPI_CSI2_DT_FE			0x01
> @@ -44,4 +46,32 @@
>  #define MIPI_CSI2_DT_RAW20		0x2f
>  #define MIPI_CSI2_DT_USER_DEFINED(n)	(0x30 + (n))	/* 0..7 */
>  
> +/**
> + * struct media_bus_fmt_info - information about a media bus format
> + * @fmt: media bus format identifier (MEDIA_BUS_FMT_*)

We usually name this "code".

> + * @dt: data type define in MIPI spec (MIPI_CSI2_DT *)
> + * @bpp: bit width per pixel

You will need to define this much more precisely. In particular, how is
padding handled ? How about compressed formats such as JPEG ? How about
the LVDS formats, how are the control bits accounted for ?

I understand you're trying to share code between two drivers, but I'm
not sure we will be able to come up with a standard definition of bpp
that will match the needs of all drivers. It feels that this information
would be better stored in driver-specific tables.

> + */
> +struct media_bus_fmt_info {
> +	u32 fmt;
> +	u32 dt;
> +	u8 bpp;
> +};
> +
> +const struct media_bus_fmt_info *media_bus_fmt_info_get(u32 bus_fmt);
> +
> +static inline int media_bus_fmt_to_csi2_dt(int bus_fmt)
> +{
> +	const struct media_bus_fmt_info *info = media_bus_fmt_info_get(bus_fmt);
> +
> +	return info ? info->dt : 0;
> +}
> +
> +static inline int media_bus_fmt_to_csi2_bpp(int bus_fmt)
> +{
> +	const struct media_bus_fmt_info *info = media_bus_fmt_info_get(bus_fmt);
> +
> +	return info ? info->bpp : 0;
> +}
> +

These are not specific to CSI-2, they belong to a different header.
v4l2-common.h is an option, given that the implementation goes to
v4l2-common.c.

>  #endif /* _MEDIA_MIPI_CSI2_H */
> 
> 

-- 
Regards,

Laurent Pinchart