Hi Guennadi,
On 06/29/2011 06:27 PM, Guennadi Liakhovetski wrote:
> Add media bus configuration types and two subdev operations to get
> supported mediabus configurations and to set a specific configuration.
> Subdevs can support several configurations, e.g., they can send video data
> on 1 or several lanes, can be configured to use a specific CSI-2 channel,
> in such cases subdevice drivers return bitmasks with all respective bits
> set. When a set-configuration operation is called, a non-ambiguous
> configuration has to be specified.
>
> Signed-off-by: Stanimir Varbanov<svarbanov@xxxxxxxxxx>
> Signed-off-by: Guennadi Liakhovetski<g.liakhovetski@xxxxxx>
> ---
>
> v4: more comments by Hans:
>
> 1. one more variable type to unsigned int
>
> 2. master mode clarified
>
> 3. switch-case fall-through commented
>
> 4. more BT.656, BT.1120 commenting
>
> 5. .s_mbus_config() marked as soc-camera compatibility
>
> v3: addressed comments by Hans - thanks!
>
> 1. moved too big inline function into a new .c file
>
> 2. changed flags types to int, local variables to bool, added "const"
>
> 3. accepting BT.656 now too
>
> v2:
>
> 1. Removed parallel bus width flags. As Laurent correctly pointed out, bus
> width can be configured based on the mediabus format.
>
> 2. Removed the clock parameter for now. Passing timing information between
> the subdevices and the host / bridge driver is indeed necessary, but it is
> not yet quite clear, what is the best way to do this. This requires more
> thinking and can be added as an extra field to struct v4l2_mbus_config
> later. The argument, that "struct clk" is still platform specific is
> correct, but I am too tempted by the possibilities, the clkdev offers us
> to give up this idea immediatrely. Maybe drivers, that need such a clock,
> could use a platform callback to create a clock instance for them, or get
> a clock object from the platform with platform data. However, there are
Doesn't sound like a good idea to me to be passing clock pointers in platform
data (if that's what you mean) or adding additional callbacks there.
Would such callback be implemented in a board setup file, which are
being phased out in favour of the device tree?
> also opinions, that the clkdev API is completely unsuitable for this
> purpose. I'd commit this without any timing first, and consider
> possibilities as a second step.
>
> drivers/media/video/Makefile | 2 +-
> include/media/v4l2-mediabus.h | 66 +++++++++++++++++++++++++++++++++++++++++
> include/media/v4l2-subdev.h | 10 ++++++
> 3 files changed, 77 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
> index 459db02..e0223ce 100644
> --- a/drivers/media/video/Makefile
> +++ b/drivers/media/video/Makefile
> @@ -11,7 +11,7 @@ stkwebcam-objs := stk-webcam.o stk-sensor.o
> omap2cam-objs := omap24xxcam.o omap24xxcam-dma.o
>
> videodev-objs := v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
> - v4l2-event.o v4l2-ctrls.o v4l2-subdev.o
> + v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-mediabus.o
>
> # V4L2 core modules
>
> diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h
> index 971c7fa..e0fb39a 100644
> --- a/include/media/v4l2-mediabus.h
> +++ b/include/media/v4l2-mediabus.h
> @@ -13,6 +13,72 @@
>
> #include<linux/v4l2-mediabus.h>
>
> +/* Parallel flags */
> +/*
> + * Can the client run in master or in slave mode. By "Master mode" an operation
> + * mode is meant, when the client (e.g., a camera sensor) is producing
> + * horizontal and vertical synchronisation. In "Slave mode" the host is
> + * providing these signals to the slave.
> + */
> +#define V4L2_MBUS_MASTER (1<< 0)
> +#define V4L2_MBUS_SLAVE (1<< 1)
> +/* Which signal polarities it supports */
> +/* Note: in BT.656 mode HSYNC and VSYNC are unused */
> +#define V4L2_MBUS_HSYNC_ACTIVE_HIGH (1<< 2)
> +#define V4L2_MBUS_HSYNC_ACTIVE_LOW (1<< 3)
> +#define V4L2_MBUS_VSYNC_ACTIVE_HIGH (1<< 4)
> +#define V4L2_MBUS_VSYNC_ACTIVE_LOW (1<< 5)
> +#define V4L2_MBUS_PCLK_SAMPLE_RISING (1<< 6)
> +#define V4L2_MBUS_PCLK_SAMPLE_FALLING (1<< 7)
> +#define V4L2_MBUS_DATA_ACTIVE_HIGH (1<< 8)
> +#define V4L2_MBUS_DATA_ACTIVE_LOW (1<< 9)
> +
> +/* Serial flags */
> +/* How many lanes the client can use */
> +#define V4L2_MBUS_CSI2_1_LANE (1<< 0)
> +#define V4L2_MBUS_CSI2_2_LANE (1<< 1)
> +#define V4L2_MBUS_CSI2_3_LANE (1<< 2)
> +#define V4L2_MBUS_CSI2_4_LANE (1<< 3)
> +/* On which channels it can send video data */
> +#define V4L2_MBUS_CSI2_CHANNEL_0 (1<< 4)
> +#define V4L2_MBUS_CSI2_CHANNEL_1 (1<< 5)
> +#define V4L2_MBUS_CSI2_CHANNEL_2 (1<< 6)
> +#define V4L2_MBUS_CSI2_CHANNEL_3 (1<< 7)
> +/* Does it support only continuous or also non-continuous clock mode */
> +#define V4L2_MBUS_CSI2_CONTINUOUS_CLOCK (1<< 8)
> +#define V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK (1<< 9)
> +
> +#define V4L2_MBUS_CSI2_LANES (V4L2_MBUS_CSI2_1_LANE | V4L2_MBUS_CSI2_2_LANE | \
> + V4L2_MBUS_CSI2_3_LANE | V4L2_MBUS_CSI2_4_LANE)
> +#define V4L2_MBUS_CSI2_CHANNELS (V4L2_MBUS_CSI2_CHANNEL_0 | V4L2_MBUS_CSI2_CHANNEL_1 | \
> + V4L2_MBUS_CSI2_CHANNEL_2 | V4L2_MBUS_CSI2_CHANNEL_3)
> +
> +/**
> + * v4l2_mbus_type - media bus type
> + * @V4L2_MBUS_PARALLEL: parallel interface with hsync and vsync
> + * @V4L2_MBUS_BT656: parallel interface with embedded synchronisation, can
> + * also be used for BT.1120
> + * @V4L2_MBUS_CSI2: MIPI CSI-2 serial interface
> + */
> +enum v4l2_mbus_type {
> + V4L2_MBUS_PARALLEL,
> + V4L2_MBUS_BT656,
> + V4L2_MBUS_CSI2,
How about internal connections between processing blocks inside SoCs?
Don't we want to also list those here? I mean direct connections
like Preview Engine -> Resizer in TI SoCs or Display Mixer -> Video Capture
Engine in Samsung SoCs.
If there is no all possible bus types in this list I can't see how
driver's for such hardware could be converted to use this new interface.
Perhaps we could add something like
V4L2_MBUS_INTERNAL or V4L2_MBUS_USER1...?
> +};
Thanks,
Sylwester
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