Guennadi,
From: [email protected] [mailto:linux-media-
[email protected]] On Behalf Of Guennadi Liakhovetski
Sent: Wednesday, September 02, 2009 7:34 AM
> To: Linux Media Mailing List
> Cc: Hans Verkuil; Paulius Zaleckas; Robert Jarzmik; Kuninori Morimoto;
> Laurent Pinchart; Karicheri, Muralidharan
> Subject: [PATCH 2/3] v4l: add an image-bus API for configuring v4l2 subdev
> pixel and frame formats
>
> Video subdevices, like cameras, decoders, connect to video bridges over
> specialised busses. Data is being transferred over these busses in various
> formats, which only loosely correspond to fourcc codes, describing how
> video
> data is stored in RAM. This is not a one-to-one correspondence, therefore
> we
> cannot use fourcc codes to configure subdevice output data formats. This
> patch
> adds codes for several such on-the-bus formats and an API, similar to the
> familiar .s_fmt(), .g_fmt(), .try_fmt(), .enum_fmt() API for configuring
> those
> codes. After all users of the old API in struct v4l2_subdev_video_ops are
> converted, the API will be removed.
>
> Signed-off-by: Guennadi Liakhovetski <[email protected]>
> ---
> drivers/media/video/Makefile | 2 +-
> drivers/media/video/v4l2-imagebus.c | 196
> +++++++++++++++++++++++++++++++++++
> include/media/v4l2-imagebus.h | 80 ++++++++++++++
> include/media/v4l2-subdev.h | 10 ++-
> 4 files changed, 286 insertions(+), 2 deletions(-)
> create mode 100644 drivers/media/video/v4l2-imagebus.c
> create mode 100644 include/media/v4l2-imagebus.h
>
<snip>
> +const struct v4l2_imgbus_pixelfmt *v4l2_imgbus_get_fmtdesc(
> + enum v4l2_imgbus_pixelcode code)
> +{
> + if ((unsigned int)code > ARRAY_SIZE(imgbus_fmt))
> + return NULL;
> + return imgbus_fmt + code;
Wouldn't it be better to do this instead?:
return imgbus_fmt[code];
> +}
> +EXPORT_SYMBOL(v4l2_imgbus_get_fmtdesc);
> +
> +s32 v4l2_imgbus_bytes_per_line(u32 width,
> + const struct v4l2_imgbus_pixelfmt *imgf)
> +{
> + switch (imgf->packing) {
> + case V4L2_IMGBUS_PACKING_NONE:
> + return width * imgf->bits_per_sample / 8;
> + case V4L2_IMGBUS_PACKING_2X8:
> + case V4L2_IMGBUS_PACKING_EXTEND16:
> + return width * 2;
> + }
> + return -EINVAL;
> +}
> +EXPORT_SYMBOL(v4l2_imgbus_bytes_per_line);
> diff --git a/include/media/v4l2-imagebus.h b/include/media/v4l2-imagebus.h
> new file mode 100644
> index 0000000..d8c0fb8
> --- /dev/null
> +++ b/include/media/v4l2-imagebus.h
> @@ -0,0 +1,80 @@
> +/*
> + * Image Bus API header
> + *
> + * Copyright (C) 2009, Guennadi Liakhovetski <[email protected]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef V4L2_IMGBUS_H
> +#define V4L2_IMGBUS_H
> +
> +enum v4l2_imgbus_packing {
> + V4L2_IMGBUS_PACKING_NONE,
> + V4L2_IMGBUS_PACKING_2X8,
> + V4L2_IMGBUS_PACKING_EXTEND16,
> +};
> +
> +enum v4l2_imgbus_order {
> + V4L2_IMGBUS_ORDER_LE,
> + V4L2_IMGBUS_ORDER_BE,
> +};
> +
> +enum v4l2_imgbus_pixelcode {
> + V4L2_IMGBUS_FMT_YUYV,
> + V4L2_IMGBUS_FMT_YVYU,
> + V4L2_IMGBUS_FMT_UYVY,
> + V4L2_IMGBUS_FMT_VYUY,
> + V4L2_IMGBUS_FMT_VYUY_SMPTE170M_8,
> + V4L2_IMGBUS_FMT_VYUY_SMPTE170M_16,
> + V4L2_IMGBUS_FMT_RGB555,
> + V4L2_IMGBUS_FMT_RGB555X,
> + V4L2_IMGBUS_FMT_RGB565,
> + V4L2_IMGBUS_FMT_RGB565X,
> + V4L2_IMGBUS_FMT_SBGGR8,
> + V4L2_IMGBUS_FMT_SGBRG8,
> + V4L2_IMGBUS_FMT_SGRBG8,
> + V4L2_IMGBUS_FMT_SRGGB8,
> + V4L2_IMGBUS_FMT_SBGGR10,
> + V4L2_IMGBUS_FMT_SGBRG10,
> + V4L2_IMGBUS_FMT_SGRBG10,
> + V4L2_IMGBUS_FMT_SRGGB10,
> + V4L2_IMGBUS_FMT_GREY,
> + V4L2_IMGBUS_FMT_Y16,
> + V4L2_IMGBUS_FMT_Y10,
> + V4L2_IMGBUS_FMT_SBGGR10_2X8,
> +};
> +
> +/**
> + * struct v4l2_imgbus_pixelfmt - Data format on the image bus
> + * @fourcc: Fourcc code...
> + * @colorspace: and colorspace, that will be obtained if the
> data
> is
> + * stored in memory in the following way:
> + * @bits_per_sample: How many bits the bridge has to sample
> + * @packing: Type of sample-packing, that has to be used
> + * @order: Sample order when storing in memory
> + */
> +struct v4l2_imgbus_pixelfmt {
> + u32 fourcc;
I see that you're using __u32 later on.
Perhaphs you may want to keep consistency.
> + enum v4l2_colorspace colorspace;
> + const char *name;
> + enum v4l2_imgbus_packing packing;
> + enum v4l2_imgbus_order order;
> + u8 bits_per_sample;
Similarly here.
> +};
> +
> +struct v4l2_imgbus_framefmt {
> + __u32 width;
> + __u32 height;
> + enum v4l2_imgbus_pixelcode code;
> + enum v4l2_field field;
> +};
> +
> +const struct v4l2_imgbus_pixelfmt *v4l2_imgbus_get_fmtdesc(
> + enum v4l2_imgbus_pixelcode code);
> +s32 v4l2_imgbus_bytes_per_line(u32 width,
> + const struct v4l2_imgbus_pixelfmt *imgf);
> +
> +#endif
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 81b90d2..daf8620 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -22,6 +22,7 @@
> #define _V4L2_SUBDEV_H
>
> #include <media/v4l2-common.h>
> +#include <media/v4l2-imagebus.h>
>
> struct v4l2_device;
> struct v4l2_subdev;
> @@ -194,7 +195,7 @@ struct v4l2_subdev_audio_ops {
> s_std_output: set v4l2_std_id for video OUTPUT devices. This is
> ignored by
> video input devices.
>
> - s_crystal_freq: sets the frequency of the crystal used to generate the
> + s_crystal_freq: sets the frequency of the crystal used to generate the
> clocks in Hz. An extra flags field allows device specific
> configuration
> regarding clock frequency dividers, etc. If not used, then set flags
> to 0. If the frequency is not supported, then -EINVAL is returned.
> @@ -204,6 +205,8 @@ struct v4l2_subdev_audio_ops {
>
> s_routing: see s_routing in audio_ops, except this version is for
> video
> devices.
> +
> + enum_imgbus_fmt: enumerate pixel formats provided by a video data
> source
How about documenting the others?
- g_imgbus_fmt
- try_imgbus_fmt
- s_imgbus_fmt
Regards,
Sergio
> */
> struct v4l2_subdev_video_ops {
> int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32
> config);
> @@ -225,6 +228,11 @@ struct v4l2_subdev_video_ops {
> int (*s_crop)(struct v4l2_subdev *sd, struct v4l2_crop *crop);
> int (*g_parm)(struct v4l2_subdev *sd, struct v4l2_streamparm
> *param);
> int (*s_parm)(struct v4l2_subdev *sd, struct v4l2_streamparm
> *param);
> + int (*enum_imgbus_fmt)(struct v4l2_subdev *sd, int index,
> + enum v4l2_imgbus_pixelcode *code);
> + int (*g_imgbus_fmt)(struct v4l2_subdev *sd, struct
> v4l2_imgbus_framefmt *fmt);
> + int (*try_imgbus_fmt)(struct v4l2_subdev *sd, struct
> v4l2_imgbus_framefmt *fmt);
> + int (*s_imgbus_fmt)(struct v4l2_subdev *sd, struct
> v4l2_imgbus_framefmt *fmt);
> };
>
> /**
> --
> 1.6.2.4
>
> --
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