[PATCH 2/4 v7] drm/bridge: Provide a way to embed timing info in bridges

[Archit Taneja]

On 01/12/2018 01:18 PM, Linus Walleij wrote:
> After some discussion and failed patch sets trying to convey
> the right timing information between the display engine and
> a bridge using the connector, I try instead to use an optional
> timing information container in the bridge itself, so that
> display engines can retrieve it from any bridge and use it to
> determine how to drive outputs.

queued to drm-misc-next after fixing a minor checkpatch warning
regarding a line exceeding 80 characters.

Thanks,
Archit

> 
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
> ChangeLog v6->v7:
> - Fix the comment style to use the new inline type of kerneldoc
>    for struct members.
> - Need an explicit ACK/review by someone on this patch to continue
>    with the series...
> ChangeLog v5->v6:
> - Sort forward struct declarations alphabetically
> - Switch to using DRM_BUS_FLAG_PIXDATA_[POS|NEG]EDGE to indicate
>    positive or negatice clock samling edge
> ChangeLog ->v5:
> - New patch
> ---
>   include/drm/drm_bridge.h | 33 +++++++++++++++++++++++++++++++++
>   1 file changed, 33 insertions(+)
> 
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 682d01ba920c..d3c2eea0bb63 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -29,6 +29,7 @@
>   #include <drm/drm_modes.h>
>   
>   struct drm_bridge;
> +struct drm_bridge_timings;
>   struct drm_panel;
>   
>   /**
> @@ -222,6 +223,35 @@ struct drm_bridge_funcs {
>   	void (*enable)(struct drm_bridge *bridge);
>   };
>   
> +/**
> + * struct drm_bridge_timings - timing information for the bridge
> + */
> +struct drm_bridge_timings {
> +	/**
> +	 * @sampling_edge:
> +	 *
> +	 * Tells whether the bridge samples the digital input signal
> +	 * from the display engine on the positive or negative edge of the clock,
> +	 * this should reuse the DRM_BUS_FLAG_PIXDATA_[POS|NEG]EDGE bitwise
> +	 * flags from the DRM connector (bit 2 and 3 valid).
> +	 */
> +	u32 sampling_edge;
> +	/**
> +	 * @setup_time_ps:
> +	 *
> +	 * Defines the time in picoseconds the input data lines must be
> +	 * stable before the clock edge.
> +	 */
> +	u32 setup_time_ps;
> +	/**
> +	 * @hold_time_ps:
> +	 *
> +	 * Defines the time in picoseconds taken for the bridge to sample the
> +	 * input signal after the clock edge.
> +	 */
> +	u32 hold_time_ps;
> +};
> +
>   /**
>    * struct drm_bridge - central DRM bridge control structure
>    * @dev: DRM device this bridge belongs to
> @@ -229,6 +259,8 @@ struct drm_bridge_funcs {
>    * @next: the next bridge in the encoder chain
>    * @of_node: device node pointer to the bridge
>    * @list: to keep track of all added bridges
> + * @timings: the timing specification for the bridge, if any (may
> + * be NULL)
>    * @funcs: control functions
>    * @driver_private: pointer to the bridge driver's internal context
>    */
> @@ -240,6 +272,7 @@ struct drm_bridge {
>   	struct device_node *of_node;
>   #endif
>   	struct list_head list;
> +	const struct drm_bridge_timings *timings;
>   
>   	const struct drm_bridge_funcs *funcs;
>   	void *driver_private;
> 

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