Hi Murali,
> From: Muralidharan Karicheri <a0868495@xxxxxxxxxxxxxxxxxxxxxxxxxx>
>
> This patch adds support for setting bus parameters such as bus type
> (Raw Bayer or Raw YUV image data bus), bus width (example 10 bit raw
> image data bus, 10 bit BT.656 etc.), and polarities (vsync, hsync, field
> etc) in sub device. This allows bridge driver to configure the sub device
> bus for a specific set of bus parameters through s_bus() function call.
> This also can be used to define platform specific bus parameters for
> host and sub-devices.
>
> Reviewed by: Hans Verkuil <hverkuil@xxxxxxxxx>
> Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
> ---
> Applies to v4l-dvb repository
>
> include/media/v4l2-subdev.h | 40
> ++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 40 insertions(+), 0 deletions(-)
>
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 1785608..2f5ec98 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -37,6 +37,43 @@ struct v4l2_decode_vbi_line {
> u32 type; /* VBI service type (V4L2_SLICED_*). 0 if no service found */
> };
>
> +/*
> + * Some sub-devices are connected to the host/bridge device through a bus
> that
> + * carries the clock, vsync, hsync and data. Some interfaces such as
> BT.656
> + * carries the sync embedded in the data where as others have separate
> line
> + * carrying the sync signals. The structure below is used to define bus
> + * configuration parameters for host as well as sub-device
> + */
> +enum v4l2_subdev_bus_type {
> + /* Raw YUV image data bus */
> + V4L2_SUBDEV_BUS_RAW_YUV,
> + /* Raw Bayer image data bus */
> + V4L2_SUBDEV_BUS_RAW_BAYER
> +};
> +
> +struct v4l2_bus_settings {
> + /* yuv or bayer image data bus */
> + enum v4l2_subdev_bus_type type;
> + /* subdev bus width */
> + u8 subdev_width;
> + /* host bus width */
> + u8 host_width;
> + /* embedded sync, set this when sync is embedded in the data stream */
> + unsigned embedded_sync:1;
> + /* master or slave */
> + unsigned host_is_master:1;
> + /* 0 - active low, 1 - active high */
> + unsigned pol_vsync:1;
> + /* 0 - active low, 1 - active high */
> + unsigned pol_hsync:1;
> + /* 0 - low to high , 1 - high to low */
> + unsigned pol_field:1;
> + /* 0 - sample at falling edge , 1 - sample at rising edge */
> + unsigned pol_pclock:1;
> + /* 0 - active low , 1 - active high */
> + unsigned pol_data:1;
> +};
I've been thinking about this for a while and I think this struct should
be extended with the host bus parameters as well:
struct v4l2_bus_settings {
/* yuv or bayer image data bus */
enum v4l2_bus_type type;
/* embedded sync, set this when sync is embedded in the data stream */
unsigned embedded_sync:1;
/* master or slave */
unsigned host_is_master:1;
/* bus width */
unsigned sd_width:8;
/* 0 - active low, 1 - active high */
unsigned sd_pol_vsync:1;
/* 0 - active low, 1 - active high */
unsigned sd_pol_hsync:1;
/* 0 - low to high, 1 - high to low */
unsigned sd_pol_field:1;
/* 0 - sample at falling edge, 1 - sample at rising edge */
unsigned sd_edge_pclock:1;
/* 0 - active low, 1 - active high */
unsigned sd_pol_data:1;
/* host bus width */
unsigned host_width:8;
/* 0 - active low, 1 - active high */
unsigned host_pol_vsync:1;
/* 0 - active low, 1 - active high */
unsigned host_pol_hsync:1;
/* 0 - low to high, 1 - high to low */
unsigned host_pol_field:1;
/* 0 - sample at falling edge, 1 - sample at rising edge */
unsigned host_edge_pclock:1;
/* 0 - active low, 1 - active high */
unsigned host_pol_data:1;
};
It makes sense since you need to setup both ends of the bus, and having
both ends defined in the same struct keeps everything together. I have
thought about having separate host and subdev structs, but part of the bus
description is always common (bus type, master/slave, embedded/separate
syncs), while another part can be different for each end of the bus.
It's all bitfields, so it is a very compact representation.
In addition, I think we need to require that at the start of the s_bus
implementation in the host or subdev there should be a standard comment
block describing the possible combinations supported by the hardware:
/* Subdevice foo supports the following bus settings:
types: RAW_BAYER (widths: 8/10/12, syncs: embedded/separate)
RAW_YUV (widths: 8/16, syncs: embedded)
bus master: slave
vsync polarity: 0/1
hsync polarity: 0/1
field polarity: not applicable
sampling edge pixelclock: 0/1
data polarity: 1
*/
This should make it easy for implementers to pick a valid set of bus
parameters.
Regards,
Hans
> +
> /* Sub-devices are devices that are connected somehow to the main bridge
> device. These devices are usually audio/video muxers/encoders/decoders
> or
> sensors and webcam controllers.
> @@ -199,6 +236,8 @@ struct v4l2_subdev_audio_ops {
>
> s_routing: see s_routing in audio_ops, except this version is for
> video
> devices.
> +
> + s_bus: set bus parameters in sub device to configure the bus
> */
> struct v4l2_subdev_video_ops {
> int (*s_routing)(struct v4l2_subdev *sd, u32 input, u32 output, u32
> config);
> @@ -219,6 +258,7 @@ struct v4l2_subdev_video_ops {
> int (*s_parm)(struct v4l2_subdev *sd, struct v4l2_streamparm *param);
> int (*enum_framesizes)(struct v4l2_subdev *sd, struct v4l2_frmsizeenum
> *fsize);
> int (*enum_frameintervals)(struct v4l2_subdev *sd, struct
> v4l2_frmivalenum *fival);
> + int (*s_bus)(struct v4l2_subdev *sd, const struct v4l2_bus_settings
> *bus);
> };
>
> struct v4l2_subdev_ops {
> --
> 1.6.0.4
>
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>
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG
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