Re: [PATCH v3 13/24] platform: add video-multiplexer subdevice driver

From: Rob Herring
Date: Tue Jan 10 2017 - 00:38:53 EST


On Fri, Jan 06, 2017 at 06:11:31PM -0800, Steve Longerbeam wrote:
> From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
>
> This driver can handle SoC internal and external video bus multiplexers,
> controlled either by register bit fields or by a GPIO. The subdevice
> passes through frame interval and mbus configuration of the active input
> to the output side.
>
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
>
> --
>
> - fixed a cut&paste error in vidsw_remove(): v4l2_async_register_subdev()
> should be unregister.
>
> - added media_entity_cleanup() and v4l2_device_unregister_subdev()
> to vidsw_remove().
>
> - there was a line left over from a previous iteration that negated
> the new way of determining the pad count just before it which
> has been removed (num_pads = of_get_child_count(np)).
>
> - Philipp Zabel has developed a set of patches that allow adding
> to the subdev async notifier waiting list using a chaining method
> from the async registered callbacks (v4l2_of_subdev_registered()
> and the prep patches for that). For now, I've removed the use of
> v4l2_of_subdev_registered() for the vidmux driver's registered
> callback. This doesn't affect the functionality of this driver,
> but allows for it to be merged now, before adding the chaining
> support.
>
> Signed-off-by: Steve Longerbeam <steve_longerbeam@xxxxxxxxxx>
> ---
> .../bindings/media/video-multiplexer.txt | 59 +++
> drivers/media/platform/Kconfig | 8 +
> drivers/media/platform/Makefile | 2 +
> drivers/media/platform/video-multiplexer.c | 472 +++++++++++++++++++++
> 4 files changed, 541 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/media/video-multiplexer.txt
> create mode 100644 drivers/media/platform/video-multiplexer.c
>
> diff --git a/Documentation/devicetree/bindings/media/video-multiplexer.txt b/Documentation/devicetree/bindings/media/video-multiplexer.txt
> new file mode 100644
> index 0000000..9d133d9
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/video-multiplexer.txt
> @@ -0,0 +1,59 @@
> +Video Multiplexer
> +=================
> +
> +Video multiplexers allow to select between multiple input ports. Video received
> +on the active input port is passed through to the output port. Muxes described
> +by this binding may be controlled by a syscon register bitfield or by a GPIO.
> +
> +Required properties:
> +- compatible : should be "video-multiplexer"

This should have an SoC/chip specific compatible string additionally.
Just need a note to that effect here, but i.MX will need a compat
string.

> +- reg: should be register base of the register containing the control bitfield
> +- bit-mask: bitmask of the control bitfield in the control register
> +- bit-shift: bit offset of the control bitfield in the control register
> +- gpios: alternatively to reg, bit-mask, and bit-shift, a single GPIO phandle
> + may be given to switch between two inputs
> +- #address-cells: should be <1>
> +- #size-cells: should be <0>
> +- port@*: at least three port nodes containing endpoints connecting to the
> + source and sink devices according to of_graph bindings. The last port is
> + the output port, all others are inputs.