From 36a776df6e088a0cec2303aacd2fe762830b2457 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Fri, 12 Jan 2018 08:48:52 +0100 Subject: [PATCH] drm/bridge: Provide a way to embed timing info in bridges 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. Signed-off-by: Linus Walleij Signed-off-by: Archit Taneja Link: https://patchwork.freedesktop.org/patch/msgid/20180112074854.9560-2-linus.walleij@linaro.org --- 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..bb7b97dfb93e 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -29,6 +29,7 @@ #include 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; -- 2.30.2